titanium tube stock Marine titanium welding process

In recent years, many new ships began extensive use of titanium alloy . With the increase in the amount of titanium alloy materials , shipyard welding to enhance efficiency , product quality and stability , the need to develop some efficient titanium welding process. TA5 two kinds of titanium Shanghai Jiangnan titanium plates for sale‍Shipbuilding in thickness of 4mm Ti70 and 16 mm for welding object, plasma arc welding , laser welding and laser - arc hybrid welding titanium welding three high energy density of the process carried out explore, get the excellent performance of welded joints

A plasma arc welding

Plasma arc welding is the use of plasma arc welding method as a heat source . Gas heated by the arc generated from the solution , a nozzle at high speed compressed by water , and increasing the energy density of the solution from forming a plasma arc. Its stability , heat and temperature are higher than the arc , and thus has a greater penetration power and welding speed . For marine titanium welding tests show that plasma arc with concentrated energy , penetration , side welding good shape , no tungsten inclusions , less porosity , etc. , it is very suitable for welding of titanium and titanium alloys . More plasma arc welding process parameters , when the method is mainly related to the use of orifice nozzle diameter , welding current, plasma gas flow rate , welding speed , shielding gas flow.

Second, laser welding

Laser welding is a focused laser beam as the heat energy generated by the bombardment of the weldment for welding a high -precision welding method . Laser welding due to the high energy density, obtained greater penetration and high welding speed , and because the diameter of the laser beam is extremely small, so narrow weld and heat -affected zone , the welding residual stress and deformation is small . The main parameters of laser welding laser welding power , welding speed , defocusing amount , side-blown gas flow and shielding gas flow. Since the laser welding high welding speed , the welding process generally can not adjust the parameters of the process , so before the formal optimum welding parameters to be determined by a combination of pre- experiments.

Third, the laser - arc hybrid welding

Compared with conventional arc welding and laser titanium plate suppliers‍ welding, laser - arc hybrid welding weld penetration with a large , high process stability , high welding efficiency , strong weld gap bridging ability and welding deformation , etc., can greatly improve the welding efficiency and weld quality. Laser - arc hybrid welding can reduce the workpiece machining accuracy requirements groove welds may be improved over time high laser welding shortage and liquid bath due to higher absorption of the laser beam , laser welding can be compared greater penetration and a higher welding speed . Using laser - arc hybrid welding , laser and arc due to the presence of two heat sources , and each heat are more parameters to be adjusted , so make the laser and arc harmonic match with a lot of tests need to be explored .

Jiangnan Shipbuilding technology test results conducted show that plasma arc welding , laser welding and laser - arc hybrid welding excellent joint performance of the welded test plate . Process repeatability, low level requirements for welders , it is very suitable for the production of large quantities of rules seam welding. Mechanical test results showed that: the mechanical properties of butt joints meet the standard requirements, joint strength and ductility in the match with a reliable base metal Ti70; plasma arc welding and laser - arc hybrid welding using low intensity TA10 wire welding Ti70 plates, welding joint seam strength far exceeds the requirements of matches with Ti70 , titanium plate suppliers‍ which makes titanium alloy welding consumables when marine greatly broaden the range of options available in between strength and ductility, toughness seek to better balance.

titanium tube stock Why study the reaction of titanium plates with steam

 Tests carried out in a vacuum apparatus with a quartz microbalance in the spring . Reading accuracy is 4 × 10 - sample surface g / cm . Mercury manometer measuring system connected to the reaction chamber using the pressure .

    Titanium iodide as a sample . Breaking titanium strip cold rolled to a rod 0.7 titanium round bar‍ mm thick . Then cut the strip size is 9 × 25 mm sample . In order to eventually remove surface dirt , before the test sample with a finely sandpaper and etched in 7% HNO3 solution in HF .

    The tube is filled with distilled water and vacuum means connected to the plug and the device as a source of water vapor . In order to remove the dissolved water gasification will remain for some time in the water under the stars . Samples were heated to a predetermined temperature in a vacuum after the tube with water and the system is turned on, and set up the equilibrium vapor pressure corresponds to the temperature in the system . When the system is full , the system is filled with water and cut off the tube , and then tested in a closed volume .

    Under 800,850,900 and 950 ℃ and 14 mm Hg vapor pressure tested titanium plate and steam reaction .

    Kinetics of these tests indicate that , in the beginning stage of the reaction , titanium rod stock‍ the reaction with water vapor titanium plates subject to the parabolic law . After the reaction started after a certain period of time becomes linear parabolic law rule.

    In order to identify the effect of pressure on the reaction rate , once at 4 mm Hg pressure two experiments .

    Titanium plate during the reaction and steam , and any of metals, and also the reaction gas , is composed by a number of successive stages , in which the main are: 1 ) the gas molecules collide with the metal , 2 ) gas molecules adsorbed on the metal surface 3 ) the dissociation of the gas molecules , 4 ) through the surface of the film agent diffusion reaction product , 5 ) chemical reaction.

    The reaction rate depends on the speed of the pro stage . It was found that the reaction pressure is reduced because the rate of 5 /6 and steam manganese remains unchanged , so it should be acknowledged that the reaction speed depends on the diffusion titanium plates for sale‍ of the reagents through the surface of the membrane , since it is the only one speed stage and the gas pressure independent .

titanium tube stock Japan successfully implemented the use of 3D printing

Japan successfully implemented the use of 3D printing make bone graft

 Japan's Kyoto University Medical Research Division teams such as August 9 titanium plates for sale‍ announced that it has made ​​a bone for different patients can be produced by the three-dimensional structure of the 3D printing technology, to four transplant patients with cervical disc successfully improved hand numb other symptoms.

    The researchers also try to do a part of the femur and spine skull . Kyoto University lecturer vine Chiun Kai said : "You can expect the technology used in the production of artificial bone resection due to a wide range of malignancies , such as bone , bone graft treatment , etc. It is believed that this technology is particularly beneficial to the complex three-dimensional shape of the pelvis titanium plate suppliers‍ and other bones . replication . "

    The team used 3D printing device to the patient's neck computed tomography (CT) data, layer by layer superimposed on a thin layer of titanium powder fired to produce a fully fit patients with cervical bone .

    Artificial chemical surface treatment and heat treatment , so that titanium plate suppliers‍ more patients with bone bonding . The artificial disc implant from the surgical removal of the success of improved hand numbness , difficulty walking and other symptoms .

    The transplant surgery is surgery clinical trials Affiliated Hospital of Kyoto University .‍

titanium plate Memory alloy pipe has been used in combination

Memory alloy pipe has been used in combination with automatic control , the sleeve may be made ​​of shape memory alloy instead of welding , is in the low temperature expansion of the tube to approximately 4% of the full , a socket assembly with a titanium plate for sale heated , shrinkage of the sleeve restore the prototype , form a tight engagement . U.S. Navy aircraft hydraulic system uses a 100,000 such joints, oil spills and damage over the years never happened . Ship and submarine oil pipeline damage , repair it with a shape memory alloy fittings, very convenient. In some parts of the inconvenience of construction , the pin made ​​of shape memory alloy , into the hole is heated to separate the trailing end automatically curl to form single assembly .

Memory alloy is particularly suitable for thermo-mechanical and automatic temperature control , automatic opening and closing has made ​​room arm can open the windows are in the sunshine during the day , automatically turns off when the night temperature drops. Memory alloy heat engine designs are also a lot that they can be in with a low temperature difference between the two media work , so as to take advantage of industrial cooling water , titanium plates for sale nuclear reactor heat, ocean thermal and solar power opened up new avenues . Now the problem is widespread efficiency is not high, only 4 % to 6% , to be further improved .

Memory alloys in medical applications is also very compelling. E.g., the bone with the bone plate , not only can two fixing broken bones , and the recovery of the original shape of the compression force is generated , forcing the broken bones are joined together . After straightening teeth using dental wire , long clip ligation of cerebral aneurysms and vas deferens , with the support plate straightening the spine , are implanted in the human body temperature by the action starts, thrombus filter is also a new product memory alloy . After being straightened filter implanted vein , will be gradually restored into a network , thereby preventing clot 95% flow to the heart and lungs.

Artificial heart is a more complex structure of the organ , muscle fibers of the titanium bar stock elastic memory alloy thin film made ​​of ventricular cooperate to mimic ventricular contraction . Now water is pumped been successful.

titanium bar stock corrosion resistance makes it highly popular in various fields

Since memory alloy is a " life has alloy " , use it at a certain temperature changes shape , you can design all kinds of self-control devices , its use is expanding . The first application of shape memory alloy pipe fittings in and fasteners . A shape memory alloy titanium plate for sale is processed into an outer diameter smaller than the internal diameter of the pipe to be connected to the casing 4% , at liquid nitrogen temperature and then expanding the sleeve diameter of about 8% , this will be removed from the cannula assembly when the liquid nitrogen , the desire inserted from both ends of the tube connection . When the temperature was raised to room temperature , i.e., the sleeve forming a holding seal shrinkage . This connection can be in close contact with anti-leakage , far better than welding , especially suitable for aviation, aerospace , nuclear industry and submarine pipelines and other dangerous situations. The most promising application memory alloys in aerospace technology . July 20, 1969 , "Apollo" 11 lunar module landed on the moon , the first human landing on the moon to achieve the dream of traveling . After the astronauts landing on the moon , on the moon a few meters in diameter placed a large hemispherical antenna for transmitting and receiving information to Earth . A few meters from a large antenna mounted on the tiny lunar module sent into space inside . Antenna that was just invented near memory alloy used. Under normal circumstances, the first predetermined requirements of good memory alloy material with a titanium plates for sale very thin , then lower the temperature to press it into a ball , bring the day to go into the lunar module . Into the lunar surface after the temperature rise in the sunlight , when it reaches the transition temperature , antennas and " mind" from their original appearance , becomes a huge domed . At present, the shape memory effect and superelasticity has been widely used in various fields of medicine and life . Thrombus filter manufacturing , spinal orthopedic rods, plates , artificial joints, women bra , artificial heart and so on. Can also be widely used in a variety of automatic regulation and control devices. Shape memory films and filaments may be the ideal material for future ultra- miniature robots and robots. titanium bar stock Especially its light weight, high strength and corrosion resistance makes it highly popular in various fields .

plate titanium Memory alloys for artificial heart

.Memory alloys for artificial heart

Memory alloy is an atomic arrangement is very rules into martensite is less than 0.5% by volume of phase change alloy . This alloy will be deformed under an external force when the external force is removed, under certain temperature conditions , can titanium plate for sale restore the original shape. Because it has more than a million times to restore function, so called " memory alloys ." Of course it is not like the human brain thinking and memory , more accurately should be called " shape memory alloys ." In addition, the memory alloy also has a non-magnetic, wear and corrosion , non-toxic advantages, so widely used. Scientists have now discovered dozens of different memory alloys , such as titanium - nickel alloy, gold - cadmium alloy, copper - zinc alloy.

What is memory alloy 1870s , the world there is a materials science with alloy " memory" shape function . Memory is a rather special alloy metal bars , it can easily be bent , we put it in the container of hot water aquarium , metal strips rushed forward ; put it into cold water , the metal strip is restored the status quo. Container of cold water in the aquarium , the stretch of a spring , when the spring into the hot water , springs and automatically folded up . Cold water in the spring to restore its original state , while in hot water , it will shrink , spring can be an unlimited number of stretching and shrinking , shrinking again opened. The memory consists of an intelligent made ​​of metal , the microstructure of which has two relatively stable at high temperatures of the alloy can be turned into any shape you want, the alloy at lower temperatures can be stretched , but if it is reheated , it will remember its original shape , and change back. This material is called memory metal (memory metal). titanium plates for sale It is mainly a nickel titanium material. For example , a helical superalloy, after high temperature annealing , which is in the shape of a spiral state. At room temperature , that is forced to use a lot of effort to straighten it , but as long as it is heated to a certain " abnormal temperature ," which seemed to root alloy remembered something, now restored to its original helical shape . How is this going ? Did alloy also has a kind of human memory ? Original not the case ! It's just the use of certain alloys law changes the crystal structure in the solid state with temperature only. For example , a nickel - titanium alloy 40oC 40oC above and below the crystal structure is different, but the temperature change in the vertical 40oC , will be contracted or expanded metal , such that its shape is changed . Here , 40oC is a nickel - titanium shape memory alloy "abnormal temperature ." Various alloys have their own perverted temperature. Abnormal high temperature superalloys above that . At high temperatures it is spirally formed in a stable state . At room temperature when it forcibly straightened, it is in an unstable state , so long as it is heated to a temperature of metamorphosis , it is immediately restored to the spiral shape of the original is in a stable state . Classification and application of shape memory alloy can be divided into three types: ( 1 ) one-way shape memory alloy memory effect deformation at low temperature before heating the deformed shape recoverability , which exists only in the heating process of shape memory One way is called memory effect . ( 2 ) Two-way memory effect of certain alloys with shape recovery temperature heating , cooling can restore the shape of the low temperature phase , called the two-way memory effect. ( 3 ) recovery throughout the high-temperature phase shape memory effect heating , cooling into the same shape and the shape of the opposite orientation of the low-temperature phase , called the whole memory effect. Three kinds of memory effect is shown below. Has been successfully developed TiNi shape memory alloy based shape memory alloys, copper-based shape memory alloys , iron-based shape memory alloys. The earliest reports of the shape memory effect and Read by Chang et al made ​​in 1952 . They observed Au-Cd alloy reversible phase transformation . Later in the Cu-Zn alloys also found the same phenomenon, but did not attract widespread attention . Until 1962 , Buehler and his collaborators observed with macroscopic shape memory effects such as changes in the atomic ratio of TiNi alloy , it attracted the attention of materials science and industry . By the early 1970s , CuZn, CuZnAl, CuAlNi also found in other alloys with shape memory effect martensitic transformation related . For decades, research on shape memory alloy has gradually become an important issue of international conferences and phase change materials conferences , and has held a number of symposia , and constantly enrich and improve the martensitic transformation theory . In theory deepening , while the application of shape memory alloys have also made considerable progress, its scope of application involves many areas of mechanical , electronic, chemical , aerospace , energy and medical. Specific applications of shape memory alloys below. Industrial applications: ( 1 ) the use of one-way shape memory effect of a one-way shape recovery . Such as pipe fittings, antenna , rings and so on. ( 2 ) extrinsic two-way memory recovery. Namely the use of one-way shape memory effect and lifting to do with the temperature outside help repeated actions, such as heat-sensitive components, robots, terminals , etc. ( 3 ) intrinsic two-way memory recovery. Namely the use of two-way memory effect with temperature elevating do repeated actions, such as heat engines , thermal components. But such applications faster memory decay , poor reliability , not commonly used. ( 4 ) ultra- flexible application . titanium plate for sale Such as springs , terminal, eyeglass frames and so on. Medical Applications : biocompatibility TiNi alloy good use of its shape memory effect and superelasticity medical instances considerable . If the filter thrombosis , spinal orthopedic rods, tooth orthopedic wire, cerebral aneurysm clips, plates , intramedullary nail , artificial joints, contraceptive devices , cardiac repair components, artificial kidneys using a micro- pumps. Tech applications Outlook: The 20th century was the era of mechanical and electrical science . Sensing - IC - driving is the most typical mechanical and electronic control systems, but the complexity and huge . Shape memory materials both sensing and driven dual function , the control system can achieve miniaturization and intelligent robots such as holograms , ultra- millimeter micro robots. The 21st century will be the era of e- learning materials . Action shape memory alloy robot addition to temperature conditions without any environmental impact is expected in high-tech fields reactors, accelerators , space laboratories flourish. Memory alloy spoke alloys, of course, talk about the most interesting alloys - memory alloy . Metal has a memory , an accidental discovery : the early 1960s , a research team from the U.S. Navy led to some of the warehouse nitinol wire experiments , they found that these alloy wire winding , very easy to use , so he took these alloy wire a root straightened. During the test , a strange phenomenon , they found that when the temperature rose to a certain value , which has been straightened nitinol wire suddenly restored to its original state bent , they are good at observing the heart, and repeated done several tests , the results have confirmed these filaments do ? "memory ." The discovery of Naval Research , and aroused great interest in the scientific community , a large number of scientists have conducted in-depth research . Found that zinc alloy , copper-aluminum -nickel alloy , copper-molybdenum -nickel alloy , zinc alloy, copper and gold also have this strange ability . It may be in a certain range , according to the need to change the shape of these alloys to a particular temperature, they automatically return to their original shape , and this " change - recovery " may be repeated several times , regardless of how changes they always remember the shape of his own time , to this temperature , it is no less to the prototype reproduction. It is called the shape memory effect of this phenomenon , the metal having such a shape memory effect is called a shape memory alloy , referred to as memory alloy . Why are these alloys can have such a shape memory effect ? How they remember their original shape ? With the general theory of metallic bonds , free electron theory is difficult to explain the effect of this memory alloy . Memory alloy under certain temperature conditions can be restored to original shape for sports extranuclear - movement with temperature changes , provides an excellent example. It is due to the formation of the alloy at high temperature of the liquid metal melt each other , since the structure of titanium bar stock the liquid metal element rejection , resulting in the structure of another metal element and the structure of each element of this element uniform solidification , its microstructure is ordered different types of structure element proportional to the electromagnetic force is the main object of the alloy constituting the cohesion . The electromagnetic force is formed by the valence and electronic operation of the electronic operating rate changes with temperature , so the electromagnetic force ( size, direction , action point ) is also inside the object temperature conditions. The resulting internal forces of metal objects with temperature changes , but these changes within a small range of temperature difference is not obvious , only performance only in the larger temperature changes ( several hundred degrees C) . Force in the general metal , can be plastically deformed as a wire is bent , the bending portion , the electromagnetic force by the external disturbance , resulting in operation of an electromagnetic plane and force electrons to the valence micro adjustment , a plastic deformation completed . Due to the different types of memory alloy structural element uniform blending with each other , despite the different size of the structure element tall, electromagnetic force , but each has its own price and speed up the operation , under certain temperature conditions adjacent peace and quiet . After the external force , the electromagnetic force of the external disturbance , and the valence electrons run to the plane of trace angle adjustment , the object is plastically deformed , in this plastic deformation , the price and the adjustment operation of the electronic part is not stretched . When the rate of change of temperature change with current prices and electrons when the temperature returns to the refreshing phase of development (transition temperature ) conditions , and does not stretch the valence electrons immediately run back to the time rate of change along the electromagnetic force , the adjacent structural element of price and running are also adjusted accordingly , the entire stretch back to the original state , so the whole object also return to the original state. This is the memory of the process memory alloy . In fact, the memory metal has long been found : a straight wire bent to a right angle (90 °), a release , it is necessary to restore it to form an angle larger than 90 ° . Put a bent wire straightening , it must fold to over 180 ° and then released, so that it can just return to the straight state, which is the Chinese idiom spoken overkill. There is a better memory alloy spring , ( talking about here is a steel spring , steel is an iron -carbon alloy ) spring firmly remember their shape , force a withdrawal , immediately return to their original appearance, only a wide temperature memory spring , so there is not a specific memory alloys transition temperature, which has some special functions . With the memory alloy deformation function at a particular temperature , the temperature can produce a variety of devices, the temperature control circuit can be produced , thermostatic door , temperature of the pipe connection . People have made ​​use of automatic memory alloy fire hydrant - fire temperature, memory alloy deformation, so that the valve opens, water spray fire. Making a connection to connect the mechanical parts , pipes , air refueling aircraft interface is the use of a shape memory alloy - two oil pipes tacking , the use of electric heating temperature change , the interface memory alloy deformation, so that the interface tight dripping ( oil ) does not leak . Making the area of ​​several hundred square meters of space station antenna from Fair - first made large parabolic antennas or planar , folded into a ball on the ground, with the spacecraft to the space , the temperature changes , since the development of a large area and the original shape. Memory alloys have been to dozens of current development in the aerospace, military, industrial, agricultural , medical and other fields have a purpose , and the development trend is very impressive, it is grand plans for the benefit of mankind.

Shape memory alloys have been found so far a dozen memory alloy system. Include Au-Cd, Ag-Cd, Cu-Zn, Cu-Zn-Al, Cu-Zn-Sn, Cu-Zn-Si, Cu-Sn, Cu-Zn-Ga, In-Ti, Au-Cu-Zn , NiAl, Fe-Pt, Ti-Ni, Ti-Ni-Pd, Ti-Nb, U-Nb and Fe-Mn-Si , etc.

Application memory alloy application memory alloy is widely used. For example, the fastening pin machinery, fittings, fire alarm on electronic equipment , connectors , integrated circuits, soldering , artificial heart valves for medical , chiropractic stick, skull repair surgery, orthopedic and oral teeth mandible repair surgery. It will also play a magical performance in a communications satellite , color TV , temperature controllers and toys , etc., will also be new material on all fronts , modern maritime, aviation , aerospace , transportation , textile and so on.

titanium plate suppliers the world there is a materials science with alloy

Memory alloys for artificial heart
Memory alloy is an atomic arrangement is very rules into martensite is less than 0.5% by volume of phase change alloy . This alloy will be deformed under an external force when the external force is removed, under certain temperature conditions , can restore the original shape. Because it has more than a million times to restore function, titanium plate for sale so called " memory alloys ." Of course it is not like the human brain thinking and memory , more accurately should be called " shape memory alloys ." In addition, the memory alloy also has a non-magnetic, wear and corrosion , non-toxic advantages, so widely used. Scientists have now discovered dozens of different memory alloys , such as titanium - nickel alloy, gold - cadmium alloy, copper - zinc alloy.

What is memory alloy 1870s , the world there is a materials science with alloy " memory" shape function . Memory is a rather special alloy metal bars , it can easily be bent , we put it in the container of hot water aquarium , metal strips rushed forward ; put it into cold water , the metal strip is restored the status quo. Container of cold water in the aquarium , the stretch of a spring , when the spring into the hot water , springs and automatically folded up . Cold water in the spring to restore its original state , while in hot water , it will shrink , spring can be an unlimited number of stretching and shrinking , shrinking again opened. The memory consists of an intelligent made ​​of metal , the microstructure of which has two relatively stable at high temperatures of the alloy can be turned into any shape you want, the alloy at lower temperatures can be stretched , but if it is reheated , it will remember its original shape , and change back. This material is called memory metal (memory metal). It is mainly a nickel titanium material. For titanium bar stock example , a helical superalloy, after high temperature annealing , which is in the shape of a spiral state. At room temperature , that is forced to use a lot of effort to straighten it , but as long as it is heated to a certain " abnormal temperature ," which seemed to root alloy remembered something, now restored to its original helical shape . How is this going ? Did alloy also has a kind of human memory ? Original not the case ! It's just the use of certain alloys law changes the crystal structure in the solid state with temperature only. For example , a nickel - titanium alloy 40oC 40oC above and below the crystal structure is different, but the temperature change in the vertical 40oC , will be contracted or expanded metal , such that its shape is changed . Here , 40oC is a nickel - titanium shape memory alloy "abnormal temperature ." Various alloys have their own perverted temperature. Abnormal high temperature superalloys above that . At high temperatures it is spirally formed in a stable state . At room temperature when it forcibly straightened, it is in an unstable state , so long as it is heated to a temperature of metamorphosis , it is immediately restored to the spiral shape of the original is in a stable state . Classification and application of shape memory alloy can be divided into three types: ( 1 ) one-way shape memory alloy memory effect deformation at low temperature before heating the deformed shape recoverability , which exists only in the heating process of shape memory One way is called memory effect . ( 2 ) Two-way memory effect of certain alloys with shape recovery temperature heating , cooling can restore the shape of the low temperature phase , called the two-way memory effect. ( 3 ) recovery throughout the high-temperature phase shape memory effect heating , cooling into the same shape and the shape of the opposite orientation of the low-temperature phase , called the whole memory effect. Three kinds of memory effect is shown below. Has been successfully developed TiNi shape memory alloy based shape memory alloys, copper-based shape memory alloys , iron-based shape memory alloys. The earliest reports of the shape memory effect and Read by Chang et al made ​​in 1952 . They observed Au-Cd alloy reversible phase transformation . Later in the Cu-Zn alloys also found the same phenomenon, but did not attract widespread attention . Until 1962 , Buehler and his collaborators observed with macroscopic shape memory effects such as changes in the atomic ratio of TiNi alloy , it attracted the attention of materials science and industry . By the early 1970s , CuZn, CuZnAl, CuAlNi also found in other alloys with shape memory effect martensitic transformation related . For decades, research on shape memory alloy has gradually become an important issue of international conferences and phase change materials conferences , and has held a number of symposia , and constantly enrich and improve the martensitic transformation theory . In theory deepening , while the application of shape memory alloys have also made considerable progress, its scope of application involves many areas of mechanical , electronic, chemical , aerospace , energy and medical. Specific applications of shape memory alloys below. Industrial applications: ( 1 ) the use of one-way shape memory effect of a one-way shape recovery . Such as pipe fittings, antenna , rings and so on. ( 2 ) extrinsic two-way memory recovery. Namely the use of one-way shape memory effect and lifting to do with the temperature outside help repeated actions, such as heat-sensitive components, robots, terminals , etc. ( 3 ) intrinsic two-way memory recovery. Namely the use of two-way memory effect with temperature elevating do repeated actions, such as heat engines , thermal components. But such applications faster memory decay , poor reliability , not commonly used. ( 4 ) ultra- flexible application . Such as springs , terminal, eyeglass frames and so on. Medical Applications : titanium tube stock biocompatibility TiNi alloy good use of its shape memory effect and superelasticity medical instances considerable . If the filter thrombosis , spinal orthopedic rods, tooth orthopedic wire, cerebral aneurysm clips, plates , intramedullary nail , artificial joints, contraceptive devices , cardiac repair components, artificial kidneys using a micro- pumps. Tech applications Outlook: The 20th century was the era of mechanical and electrical science . Sensing - IC - driving is the most typical mechanical and electronic control systems, but the complexity and huge . Shape memory materials both sensing and driven dual function , the control system can achieve miniaturization and intelligent robots such as holograms , ultra- millimeter micro robots. The 21st century will be the era of e- learning materials . Action shape memory alloy robot addition to temperature conditions without any environmental impact is expected in high-tech fields reactors, accelerators , space laboratories flourish. Memory alloy spoke alloys, of course, talk about the most interesting alloys - memory alloy . Metal has a memory , an accidental discovery : the early 1960s , a research team from the U.S. Navy led to some of the warehouse nitinol wire experiments , they found that these alloy wire winding , very easy to use , so he took these alloy wire a root straightened. During the test , a strange phenomenon , they found that when the temperature rose to a certain value , which has been straightened nitinol wire suddenly restored to its original state bent , they are good at observing the heart, and repeated done several tests , the results have confirmed these filaments do ? "memory ." The discovery of Naval Research , and aroused great interest in the scientific community , a large number of scientists have conducted in-depth research . Found that zinc alloy , copper-aluminum -nickel alloy , copper-molybdenum -nickel alloy , zinc alloy, copper and gold also have this strange ability . It may be in a certain range , according to the need to change the shape of these alloys to a particular temperature, they automatically return to their original shape , and this " change - recovery " may be repeated several times , regardless of how changes they always remember the shape of his own time , to this temperature , it is no less to the prototype reproduction. It is called the shape memory effect of this phenomenon , the metal having such a shape memory effect is called a shape memory alloy , referred to as memory alloy . Why are these alloys can have such a shape memory effect ? How they remember their original shape ? With the general theory of metallic bonds , free electron theory is difficult to explain the effect of this memory alloy . Memory alloy under certain temperature conditions can be restored to original shape for sports extranuclear - movement with temperature changes , provides an excellent example. It is due to the formation of the alloy at high temperature of the liquid metal melt each other , since the structure of the liquid metal element rejection , resulting in the structure of another metal element and the structure of each element of this element uniform solidification , its microstructure is ordered different types of structure element proportional to the electromagnetic force is the main object of the alloy constituting the cohesion . The electromagnetic force is formed by the valence and electronic operation of the electronic operating rate changes with temperature , so the electromagnetic force ( size, direction , action point ) is also inside the object temperature conditions. The resulting internal forces of metal objects with temperature changes , but these changes within a small range of temperature difference is not obvious , only performance only in the larger temperature changes ( several hundred degrees C) . Force in the general metal , can be plastically deformed as a wire is bent , the bending portion , the electromagnetic force by the external disturbance , resulting in operation of an electromagnetic plane and force electrons to the valence micro adjustment , a plastic deformation completed . Due to the different types of memory alloy structural element uniform blending with each other , despite the different size of the structure element tall, electromagnetic force , but each has its own price and speed up the operation , under certain temperature conditions adjacent peace and quiet . After the external force , the electromagnetic force of the external disturbance , and the valence electrons run to the plane of trace angle adjustment , the object is plastically deformed , in this plastic deformation , the price and the adjustment operation of the electronic part is not stretched . When the rate of change of temperature change with current prices and electrons when the temperature returns to the refreshing phase of development (transition temperature ) conditions , and does not stretch the valence electrons immediately run back to the time rate of change along the electromagnetic force , the adjacent structural element of price and running are also adjusted accordingly , the entire stretch back to the original state , so the whole object also return to the original state. This is the memory of the process memory alloy . In fact, the memory metal has long been found : a straight wire bent to a right angle (90 °), a release , it is necessary to restore it to form an angle larger than 90 ° . Put a bent wire straightening , it must fold to over 180 ° and then released, so that it can just return to the straight state, which is the Chinese idiom spoken overkill. There is a better memory alloy spring , ( talking about here is a steel spring , steel is an iron -carbon alloy ) spring firmly remember their shape , force a withdrawal , immediately return to their original appearance, only a wide temperature memory spring , so there is not a specific memory alloys transition temperature, which has some special functions . With the memory alloy deformation function at a particular temperature , the temperature can produce a variety of devices, the temperature control circuit can be produced , thermostatic door , temperature of the pipe connection . People have made ​​use of automatic memory alloy fire hydrant - fire temperature, memory alloy deformation, so that the valve opens, water spray fire. Making a connection to connect the mechanical parts , pipes , air refueling aircraft interface is the use of a shape memory alloy - two oil pipes tacking , the use of electric heating temperature change , the interface memory alloy deformation, so that the interface tight dripping ( oil ) does not leak . Making the area of ​​several hundred square meters of space station antenna from Fair - first made large parabolic antennas or planar , folded into a ball on the ground, with the spacecraft to the space , the temperature changes , since the development of a large area and the original shape. Memory alloys have been to dozens of current development in the aerospace, military, industrial, agricultural , medical and other fields have a purpose , and the development trend is very impressive, it is grand plans for the benefit of mankind.

Shape memory alloys have been found so far a dozen memory alloy system. Include Au-Cd, Ag-Cd, Cu-Zn, Cu-Zn-Al, Cu-Zn-Sn, Cu-Zn-Si, Cu-Sn, Cu-Zn-Ga, In-Ti, Au-Cu-Zn , NiAl, Fe-Pt, Ti-Ni, Ti-Ni-Pd, Ti-Nb, U-Nb and Fe-Mn-Si , etc.

Application memory alloy application memory alloy is widely used. For example, the fastening pin machinery, fittings, fire alarm on electronic equipment , connectors , integrated circuits, soldering , artificial heart valves for medical , chiropractic stick, skull repair surgery, orthopedic and oral teeth mandible repair surgery. It will also play a magical performance in a communications satellite , color TV , temperature controllers and toys , etc., will also be new material on all fronts , modern maritime, aviation , aerospace , transportation , textile and so on.

Memory alloy pipe has been used in combination with automatic control , the sleeve may be made ​​of shape memory alloy instead of welding , is in the low temperature expansion of the tube to approximately 4% of the full , a socket assembly with a heated , shrinkage of the sleeve restore the prototype , form a tight engagement . U.S. Navy aircraft hydraulic system uses a 100,000 such joints, oil spills and damage over the years never happened . Ship and submarine oil pipeline damage , repair it with a shape memory alloy fittings, very convenient. In some parts of the inconvenience of construction , the pin made ​​of shape memory alloy , into the hole is heated to separate the trailing end automatically curl to form single assembly .

Memory alloy is particularly suitable for thermo-mechanical and automatic temperature control , automatic opening and closing has made ​​room arm can open the windows are in the sunshine during the day , automatically turns off when the night temperature drops. Memory alloy heat engine designs are also a lot that they can be in with a low temperature difference between the two media work , so as to take advantage of industrial cooling water , nuclear reactor heat, ocean thermal and solar power opened up new avenues . Now the problem is widespread efficiency is not high, only 4 % to 6% , to be further improved .