2013年12月30日星期一

Common forms a stable element in titanium plate in

The main elements of a stable aluminum , gallium , germanium, lanthanum , cerium, neodymium and oxygen , carbon, nitrogen, boron , etc. Recently, some people think scandium and hafnium may also fall into this category . In the industrial application of the most widely used titanium alloy a stable element is aluminum. In recent years, in the development of nearly a gallium -based superalloy CKS growing importance . Therefore ,medical titanium bar there will be described focusing on the role of aluminum and gallium .

1 Ti - Al binary system
The maximum solubility of aluminum in β titanium appeared in 1460 ℃, about 30%. The maximum solubility of aluminum in a titanium appeared in 1080 ℃, about a 11%, 550 ℃ , the solubility of aluminum in a titanium is about 7.5%. There will be two compounds , r phase and a2 -phase general phase diagram . r is an ordered phase based compound TiAL , with a face -centered tetragonal ( almost tetragonal ) lattice ; a = 4.005 Å , c = 4.073 Å , c / a = 1.0162. a2 -phase compound is an ordered group of Ti2AL having a hexagonal lattice , a = 5.8730 Å , c = 4.6543 Å , c / a = 0.8047. a2 phase transition phase can come from the β.

2 titanium - gallium
Titanium - Titanium binary gallium , gallium β titanium solution temperature maximum occurs at about 1500 ℃, approximately 38% (30 atomic% ) . Gallium in a maximum solid titanium in 940 ℃ about 17% (13 atomic% ) . Solubility decreases as the temperature decreases .tittanium bar General a2 phase is the phase diagram for the orderly phase -based Ti3Ga .

2013年12月29日星期日

and the role of a β elements of titanium and titanium plate

Titanium is a very active metal element , and the effect of a number of elements which can occur, titanium stockist but can affect the properties of titanium and titanium alloys and titanium only those continuous or discontinuous elements of the solid solution is formed .

Role 1.β stabilizing element in titanium and titanium alloys in

β stabilizing elements include titanium located on the right side of the periodic table almost all transition elements and IB elements , about 30 species. The only real common dozen . Wherein the isomorphous β stabilizing elements molybdenum , vanadium, tantalum , niobium, eutectoid β stabilizing elements iron, chromium, manganese, copper , cobalt, nickel, tungsten, palladium and hydrogen. The unique role of hydrogen on titanium alloy will be described in relation to the impact of interstitial elements in titanium .

2.a role in stabilizing element in titanium and titanium alloys

The main elements of a stable aluminum , gallium , germanium, lanthanum , cerium, neodymium and oxygen ,titanium wire carbon, nitrogen, boron , etc. Titanium and titanium alloys in the industry 's most widely used is aluminum a stable element . Titanium aluminum can improve the tensile strength at room temperature and high temperature , high temperature has little effect on plasticity . Within the range of solubility , aluminum can effectively improve the elastic modulus of titanium , shear modulus, specific resistance and line expansion coefficient .

2013年12月24日星期二

Aluminum and gallium affect the performance of titanium plate

Aluminum and titanium, gallium can increase a + β / β transformation point . 10% aluminum phase transition point can be increased to about 1080 ℃. Gallium ability weaker . Aluminum titanium start improving recrystallization temperature of titanium alloys martensitic transformation start point (MS) is not affected. Excess aluminum and gallium in Ti3M generated based on the ordered phase a2 use temperature . Further titanium wire, the aluminum present in the metastable β phase , phase to promote ω a phase transition , thereby reducing the volume percentage of the time ω alloy phase.

Impact on the performance of aluminum and gallium , aluminum, titanium and gallium can improve the tensile strength at room temperature and high temperature has little effect on the high temperature plasticity. With increasing aluminum content of titanium - aluminum density and Poisson coefficient decreased linearly . Within the range of solubility , aluminum can effectively improve the elastic modulus of titanium , shear modulus, specific resistance and line expansion coefficient . When a2 phase, the emergence of a peak performance .

Titanium - appears to Ti3AL base of a2 ordered phase when the aluminum alloy , titanium alloy increases the tensile strength , ductility and toughness to deteriorate tittanium bar. This ordered phase is often a similar role with Ti3AL resistant titanium alloys for high temperature Ti3Ga phase in phase .

2013年12月23日星期一

Some common β titanium plate and titanium alloys

Titanium - molybdenum titanium Department
Β titanium and molybdenum having the same lattice type and molybdenum in solid solution β titanium infinite . In a solution of molybdenum titanium at 600 ℃, 0.8% , when the molybdenum content exceeds 24 ~ 28% at 650 ℃ β single phase is formed . Ti - Mo binary system in the solid state is only a ~ β polymorphic transformation. In a titanium- molybdenum solubility of increase with decreasing temperature , titanium is not a supersaturated phase decomposition problem.

2 titanium - titanium vanadium
In the solid titanium shift occurred - exactly molybdenum . Vanadium and β have the same lattice type titanium , vanadium and titanium in the β solid solution is infinite . 600 ℃, vanadium and titanium in a solid solution of 3.5%. At 650 ℃, when the vanadium content of more than 18.5 % to 20% then form a single β -phase solid solution. In the liquid - solid transition , titanium - vanadium binary liquid line appears a minimum. Solubility of vanadium in a phase of decline in tandem with temperature increase , titanium is not a relative supersaturation and its decomposition problem.

3 titanium - niobium titanium Department
Its solid-state transformation and titanium - vanadium same liquid - solid transition similar to titanium - molybdenum . Niobium and titanium infinite β solid solution .surgical implant titanium Niobium at 600 ℃ in a solution of 4% of titanium , when the Nb content exceeds about 50% of the solid solution to form a single β . Its a / a + shape titanium β phase line - molybdenum similar. Nor supersaturated solid solution decomposition problem.

4 Titanium - Tantalum Department of titanium
Tantalum is also unlimited in β titanium solid solution . 600 ℃, a degree of solid solution of tantalum and titanium is 11 % when the content of tantalum is about more than 65% to form a single β solid solution.

5 titanium - iron- titanium
Β titanium iron solubility of 25% maximum , in 1085 ℃. The maximum solid solubility of iron in a 0.5% titanium , about 590 ℃ appear , the following occurs in the eutectoid transformation temperature , the solubility of the eutectoid point of about 15% . β = a + TiFe

6 titanium - . Manganese titanium
Its titanium-rich portion of the titanium - iron binary phase diagram of the Ti-rich part similar. The maximum solid solubility of manganese in the β titanium is about 33 % in 1175 ℃. The maximum solid solubility of manganese in a titanium of about 0.5% titanium rod, in 550 ℃. Eutectoid transformation occurs at this temperature , the solubility of the eutectoid point of about 20% . β = a + TiMn

2013年12月18日星期三

Other β titanium and titanium plate series of

1 titanium - titanium chromium
And titanium - iron, titanium - different manganese , chromium solid solution in β titanium unlimited . There is a minimum point of chromium liquid line - in titanium. Chromium and titanium in a maximum solubility of about 0.5% , in 670 ℃. Here the presence of the following eutectoid transformation temperature , the solubility of the eutectic point of 15 %. β = a + TiCr2
TiCr2 is an intermetallic compound having a face centered cubic lattice in a low temperature , a = 6.940 Å ; having a hexagonal lattice at a high temperature , a = 4.900 Å , c = 7.927 Å , c / a = 1.6178, a melting point of 1350 ℃.

2 titanium - titanium copper lines
Copper maximum solid solubility of β titanium is 17 % in 990 ℃. And the maximum solid solubility of titanium in a 2.1% in 798 ℃. This occurs in the following eutectoid transformation temperature , the solubility of its eutectic point was 7.1 %. β = a + Ti2Cu
Titanium - titanium-rich portion of the copper-based compounds are the most important Ti2Cu, may occur only when the copper content of more than 40% TiCu phase .

3 titanium - tungsten titanium Department

Titanium - tungsten and titanium - chromium similar in β titanium tungsten is infinite solid solution . In the solid state , it is only one eutectoid transformation : β = a + β2
Its solubility eutectoid point about 28 % eutectoid temperature of 715 ℃. β2 -phase solid solution of tungsten is based. In the eutectoid temperature , solubility in tungsten titanium reaches a maximum of 0.8 %. Clearly, in titanium - tungsten no intermetallic compounds appear.

4 titanium - . Cobalt titanium

Cobalt β titanium maximum solubility of 17% in 1020 ℃. The maximum solid solubility of cobalt and titanium in a range of 1.0 % in 685 ℃. This occurs in the following eutectoid transformation temperature , the solubility of the eutectoid point was 9.5 %. β = a + Ti2Co
Titanium - cobalt titanium-rich part of the binary phase diagram has between two metal compounds : Ti2Co and TiCo. The former is the analysis of the product of the latter only in 38% or more of cobalt .

5 titanium - nickel titanium alloy

Nickel solid solution of β titanium maximum of 13 % in 955 ℃. Nickel- titanium in a solution of 0.2% maximum , in 770 ℃. This occurs in the following eutectoid transformation temperature medical titanium plates, its solubility eutectoid point to 5.0 %. β = a + Ti2Ni
Titanium - nickel titanium-rich part of the binary phase diagram between the two main metal compounds : Ti2Ni and TiNi. The former is eutectoid product , which exists only when more than 38% of nickel .

6 titanium - . Palladium titanium

Palladium maximum solid titanium β of about 49.94% , in 1140 ℃. Palladium and titanium in a solution of about 2.41% maximum , in 578 ℃. In the presence of the following eutectoid transformation temperature , the solubility of the eutectoid point to 24.92% . β = a + Ti4Pd
Obviously , titanium - titanium-rich part of the binary phase diagram of palladium only one intermetallic compound.

7 titanium - titanium silicon

Si in solid solution of β titanium maximum of about 3.0 % in 1340 ℃. A maximum solid solubility in silicon in an amount of 0.45% titanium , in 860 ℃. This occurs in the following eutectoid transformation temperature , its solubility eutectoid point to 0.65 percent . β = a + Ti3Si
Clearly, in titanium - the presence of silicon binary phase diagram of titanium-rich part of the two compounds : Ti3Si and Ti5Si3. The former is a low-temperature phase .titanium wire The latter is the high temperature phase , or a silicon content of more than 16.8% at room temperature exists.

titanium plate and wheelchair in the field

Titanium frames for bicycles and wheelchairs are formed in the mid-1980s , the application of the fast development of titanium , but just when the market began to heat these small , slow down the application process in the world of titanium .

A bicycle frame

In recent years due to defense cuts and uncertainty from floating aircraft industry , the U.S. production of V pipe three companies turned to the bicycle industry , but the world has been produced by a bicycle frame nor 3AI-2.5V to three Boeing 747 aircraft titanium (130t). Currently there are nearly 50 companies producing titanium bicycle , 90 percent of the world's all-titanium frame from several original equipment manufacturers (OE), 10% of the remaining half is produced by the United States itself , the United States has always already is the largest titanium bicycle producer and consumer countries .

This year is likely to be the highest annual sales of titanium frame , probably will produce 17,000 titanium frame , with a total weight of about 27 \ Materials Price $ 5,000,000 , including full titanium tubing, rods and plates .

When the benefits of a growing number of cyclists begin to understand titanium , but feel strapped , with air quality pipe production of Ti-3Al-2.5V frame , each pair of prices between 1600 and $ 3500 the whole bike selling price from $ 2400 to $ 6000 . In the past four years, commercially pure titanium tubes and non- aviation penalty -3AI-2. SV ( Sports Grade ) titanium frame made ​​popular , some sports grade titanium frame lowest retail price $ 1,000 per pair , the whole bike lowest price $ 1,700 . 1985 purchasing power with titanium frame is zero in 1990 to approximately $ 1.5 million by the end of 1995 , the purchasing power of approximately $ 5,000,000 .

2 Bicycle Parts

The bicycle component is the crankshaft connected to the positioning frame , pedal , steering wheel , etc., than the titanium member industry penalty -3 Si 1-2.5V faster frame industry , most of the parts with Ti-6AI- 4V production , mostly bar or plate processing machine parts out . Member with the Ti-6A1-4V Ti-3 bleed strength of only one frame of a 2.5V / 3 , 1997 to approximately 10t. SB cast components can increasingly common development in this respect may be greater than the slow development of machining parts , titanium supplier of titanium parts manufacturers began to offer cheaper materials , most of these low-cost bicycles grade material is actually being elimination of aeronautical materials .

3 wheelchair frame and components

Unlike in many market areas wheelchair bicycle market , the most important difference is that only a small amount of production of titanium wheelchair frame , with most of the slit pipe production of commercially pure titanium , titanium wheelchair total strength of approximately 15t.

Currently only a few companies in the United States has sufficient research and development funds to develop titanium wheelchair or purchase materials. Compared to cheaper aluminum wheelchair, wheelchair few advantages of titanium , titanium screw bolts now in addition ,titanium rod the titanium wheelchair parts industry has not yet formed , although there is a market , but very small, included only a small number of consumable parts , size of the market has not to $ 1,000,000 .

4 Material Requirements

Compact , stiffness , light weight bicycle and wheelchair drive specification for general requirements , titanium is often not the best material, and wrought aluminum and aluminum more popular , if titanium metal matrix composites (MMCs) , then the price down , may become a substitute for some of the aluminum market applications .

Bicycle rack

Material requirements of the frame is very simple, but it is particularly critical driving characteristics , so that the choice of materials in some ways more complex, most of the means of transport, structural elements and internal facilities and operating elements are separated, until recently , all the requirements of the bicycle frame suspension having structural integrity and function .titanium stockists Titanium is not yet a bicycle designed specifically for only some of the material is improved for a bicycle , most people consider to reduce the cost, but the main problem facing the receiving member is a rigid titanium rather than cost .

2013年12月16日星期一

β stabilizing element in titanium and titanium plate in

β stabilizing element in titanium and titanium alloys mainly from the solid solution strengthening and stabilizing β phase. When β stable over a certain number of elements , titanium has a strengthening effect of heat treatment .

Adding a small amount of β stabilizing element in a form close to a titanium alloy titanium alloys .medical titanium bars This alloy has a weak effect of heat strengthened . Eutectoid elements can be increased quickly at room temperature and high temperature properties of titanium alloys by precipitation compounds. In the heat is often a small amount of titanium silicon , such as TA8 so on.

In a + β titanium alloys to improve the content of such elements can improve the hardenability of the alloy, titanium metastable β titanium apparently hardenability highest . However, when used eutectoid elements should prevent the formation of compounds , causing brittleness. Use of such diverse elements should follow a small number of principles, such as TC10 titanium alloy used in 0.5% Fe and 0.5% Cu, increasing the solid solution strengthening effect. In the heat of a + β titanium alloys are often added to a small amount of fast- silicon eutectic elements to improve creep resistance .

In the β -type alloys , β is the main component of the stabilizing element . They hand the β phase retained, on the one hand from the solid solution strengthening effect . TB1 and TB2 alloys are used a lot of the same eutectic crystal elements and elements work together . At this point should also be noted that the amount of eutectoid elements added to try to avoid precipitation of compounds.

High molybdenum , high niobium titanium stabilized β is an excellent corrosion resistance to reducing media materials titanium axles. Plus palladium cobalt corrosion resistant materials and processing have long been used in foreign countries .

2013年12月15日星期日

Organizational changes during heat treatment of titanium and titanium plate

In order to improve the performance of titanium and titanium alloys , except alloys Outsider through the necessary general but also the use of appropriate heat treatment.

Organizational changes during heat treatment of titanium and titanium alloys

Titanium and titanium alloys in addition to the heating process of recovery and recrystallization cold outside the organization , as well as solution of the compound and a → β polymorphic transformation.
The second type of stress most of the process of recovery process to eliminate titanium and titanium alloy is also at a certain temperature , generated by the movement of vacancies and dislocations when making deformation . Recovery process occurs at a temperature below the recrystallization temperature, typically at 500 ~ 650 ℃.

Like other metals, titanium and titanium alloy recrystallization process is also in the organization after deformation , born in the crystalline grain nucleation and growth process. In this case the lattice type does not change, but the change of mechanical properties . This process is subject to the degree of cold deformation , heating temperature and holding time , and through the cold deformation rate, heating temperature and recrystallized grain size of the three-dimensional re- crystallized.

Titanium alloying elements on the recrystallization temperature began to influence the preceding section has been described before. In addition , niobium and cobalt , the commonly used alloying elements and impurity elements could increase the recrystallization temperature of titanium .

It should be noted , in titanium and titanium alloys , recrystallization process is often accompanied by other organizational changes . For example , the smaller the content of the β stabilizing elements near a a + β alloys and alloys , accompanied with a change in phase and the dissolved β components ; β in the heat-treatable alloy recrystallization often performed simultaneously with the re -crystallization process, or cause birth effects on subsequent aging . In addition, different types of the alloy microstructure in a different room , the deformation of the alloy phase involved different recrystallization process and characteristics are not the same surgical implant titanium. a recrystallization of the alloy in a major phase. In addition to industrial pure titanium addition , a metal cold deformation capacity is small, and therefore difficult to grain refinement effect in β -type alloy recrystallization mainly in β phase. β alloy cold deformation capacity is big, the degree of crushing grain , can be changed by recrystallization original organization . However, due to β alloy grain growth tendency of large , so the grain refinement is still more difficult. As a + β alloys, will depend on the participation of the main phase deformation , depending on the circumstances analysis, such as recrystallization TC4 alloy is mainly a phase recrystallization .

Determination of recrystallized microstructure observation and mainly uses a combination of X -ray diffraction method . When recrystallization , fine equiaxed grains appear on the fibrous tissue after deformation , while x-ray back reflection Laue diffraction ring on the start phase diagram becomes disconnected spots . For heat treatable β alloys can also be used incomplete aging (500 ℃ / 4 ~ 8 hours, air-cooled ) method displays recrystallized structure , not by incompletely recrystallized grains after aging after corrosion was dark .

It was determined that began TA2 titanium recrystallization temperature is about 550 ℃, TA7 titanium is about 600 ℃,medical titanium bar TC4 titanium alloy is about 700 ℃, TB2 alloy is 750 ℃.

2013年12月13日星期五

Heat treatment of titanium and titanium plate changes during cooling

When titanium and titanium alloy is heated to β phase, polymorphic transition a → β will occur. This process is also sometimes referred to as recrystallization. The highly pure titanium a → β transition temperature of 875 + -5 ℃. But until the β-phase fully formed, it is difficult to observe this process by optical method. In the low temperature phase β of the reason is unclear. But the experiment indicated,titanium stockist a mutual transition and β, either heating or cooling, a phase and β phase always maintain a certain Bragg Sites of the relationship. Polymorphic transformation of titanium when heated little research to date.

1 change in the slow cooling of titanium and titanium alloys
When titanium and titanium alloy is slowly cooled from β-phase region to a + β phase region, β → a polymorphic transformation to happen. In the high-titanium has been confirmed at this time of nucleation is a martensitic phase, and then grow by thermal activation process. When nucleation of the embossed surface of the sample usually also the martensitic transformation, but also to maintain a strict phase Sites of the Bragg relationship between the parent.

2. Changes in the rapid cooling of the
Changes and changes in product titanium and titanium alloy occurs when rapid cooling from the β phase region with changes in β stabilizing element content is different.

Martensitic transformation: 1.a `massive martensite orientation relationship can not be measured; acicular martensite and β phase to maintain a` Bragg Sites of the relationship habit plane is (334) β or (344 ) β. 2.a "in Ti-Mo, Ti-W, Ti-Re was found, but the Ti-V system did not; a" lattice parameter with composition changes; a "titanium plastic is reduced.

Phase formation quenching ω: ω is the size of small particles by electron microscopy observations only;titanium standard parts ω elastic modulus and hardness, the plastic drop.

2013年12月9日星期一

Effect of heat treatment in the cooling rate of TC4 titanium plate performance

First observe different temperature air-cooled . 1000 ℃ in the β -phase region has TC4 titanium alloy , and its air-cooled tissue equivalent β annealing organization . Microstructure in coarse grain boundaries and β original β grain interior needles α, this time corresponds to a high tensile strength and low tensile ductility . 950 ℃ and 930 ℃ in the upper two phase region TC4 titanium alloy specimens get different proportions of primary α phase and β phase in the heat , in the subsequent air cooling in the β -phase precipitates α transformation occurred more than a plastic needle in the microstructure primary α phase and β phase are equiaxed .surgical implant titanium Apparently born in the heat of the amount of α -phase sample 930 ℃ some more , this time with a tensile strength of about 1000 ℃ sample , but the tensile ductility and toughness is almost the highest. 830 ℃ in the lower part of the two-phase region TC4 titanium alloy , a large number of primary α phase , so that the change is not visible in the microstructure of β -phase morphology, see only the intergranular phase α β isometric born between this when tensile strength decreased slightly, but higher tensile ductility .
In addition , TC4 titanium original state before the heat treatment process on microstructure and mechanical properties of tissue microstructure after heat treatment has a great impact. On TC4 titanium alloy, can be roughly divided into two categories the original tissue . One is the above-mentioned organizations like furnace cooling after 1000 ℃, that basket -like tissue , which is produced at temperatures above the phase transition point blank firing or a small amount of deformation after processing ; other is α and β of equiaxed α or the β plus transformed tissue , which is above the phase transition point or a large amount of deformation in the process for the phase transformation point different deformations produced by processing . Experiments show that the former is difficult to change the subsequent heat treatment . Tensile ductility of this organization, annealing (700-800 ℃, heat 1 hour air-cooled ) , the ratio is usually axis ( transformation of the Canadian -born α β) organization , reduction rate, but the high temperature creep resistance and fracture toughness and high thermal salt stress corrosion resistance.
Clearly, the performance of TC4 titanium alloy is varied ,titanium whole distributor in order to ensure that the final product to get the desired performance and stability, should be considering the original tissue and heat treatment process.

2013年12月7日星期六

Titanium and titanium plate solid solution and aging treatment

Solution and aging treatment is a primary means of heat treatment of titanium and titanium reinforced . It is actually divided into solution treatment and aging treatment carried out in two steps . Solution treatment is to titanium and titanium alloy heating, insulation and rapidly cooled to room temperature operation. Aging treatment after solution treatment is the workpiece at a medium temperature range (450-550 ℃) holding a certain time after the air-cooling operation. This heat treatment method can be applied to nearly α alloy , α + compound alloy , α + β alloy and heat-treated β alloys.
Solution treatment process selection
The purpose of titanium and titanium alloy solution treatment can be effective is to keep strengthening the metastable phase . For near α and α + β type alloys , the purpose is to retain the solution treated martensite α ', α " or the amount of metastable β phase . Solution treatment temperature is usually lower than the phase transformation point selection 40-100 ℃ at this time , a certain proportion of primary α phase β -phase . β produce metastable phase in the subsequent rapid cooling . generally require cooling water quenching oil quenching may also be used it should be emphasized that these two alloys hardened be sure to quickly . delayed quenching time ,medical titanium plate product temperature decreased rapidly , α -phase nucleation in the first phase on the original β grain boundaries and grew up on the mechanical properties of hardened state . gives the quench delay operations on TC4 alloy and affect performance . usually require quench delay time can not be more than 10 seconds on the sheet even more demanding. Additionally, the complex shape of the workpiece or sheet should be taken to prevent deformation hardening .
The purpose of metastable alloy solution-treated in order to preserve the metastable β phase . Solution treatment temperature is usually selected in the α + β / β transformation point 40-80 ℃. Cooling can be air-cooled and water-cooled . To prevent deformation hardening and improving economic results generally use air cooling.
Α + alloy for some compounds , the purpose is to keep the processing solution supersaturated solid solution of β . Solution treatment temperature is generally selected just below the eutectic temperature. Such as Ti-2Cu alloy eutectic temperature of 798 ℃, the solution treatment temperature selection at 790. ℃ Cooling optional air cooling.
Incidentally , since the titanium and titanium alloy produced in the solution treated martensite on replacement elements are oversaturated not result in a large lattice distortion ,titanium pipe such as titanium martensitic steels martensitic not so hard . In addition, the intensity of metastable β phase is relatively low . Therefore , hardenability titanium and titanium alloy does not mean depth of hardening after quenching , but rather the depth of those retained in the subsequent aging in Asia can cause hardening of the stable phase. Because titanium martensite on cooling rate to be much more sensitive , it is hardening during tempering is also limited, so hardenability titanium and titanium alloy mainly refers to the depth of retained metastable β phase.

2013年12月5日星期四

What type of titanium plate and their performance is heterosexual cases

Heterosexual materials should reflect on the various mechanical properties of the index . However , relying on a single common performance index obtained by uniaxial tensile test , the material does not reflect whether the opposite sex. It needs to reflect whether the material has sex with another performance index . This index is often called plasticity than the value of their implications , called thick anisotropy index .
As to eb and et denote uniaxial tensile strain specimen width and thickness strain to deb and det represents an increase of these two strains , the current general there are two thick , that R anisotropy index value method = eb / et, r = deb / det
Tests showed that the vast majority of the material R is reduced with increasing tensile strain variables , it is generally used for a certain stretch the value of variables to be represented . Eb steel for example , is required to take the time e1 = 20% / et Fig. Thus ,titanium standard parts R can only be expressed as a performance index of the material , the plastic deformation of the plate can not be used , although a given calculation . A large number of experiments show that , r is at least in the uniform deformation stage is basically unchanged . Titanium case is true . According to the observation of the specimen and calculated titanium opposite case is as follows:
A thick anisotropic
Defined above, in a consistent way if the tensile properties of the test piece in the thickness direction of the plate surface properties of words within the thickness of anisotropy index r = 1. However, tests showed that the titanium r greater than 1 , indicating that some of the more difficult to change the thickness of the titanium .
2 , opposite the inner surface
Titanium addition to the performance properties of the sheet in the thickness direction of the distinct outer and inner surface plates of different properties in different directions , relative to the sheet along the rolling performance of a uniaxially stretched specimen preparation in different directions , the thickness of the anisotropic Index values ​​range.
3, the surface of the opposite sex
Some titanium uniaxial tensile specimen , after stretching its cross-section showing a significant curvature. This indicates that under the same elongation deformation , shrinkage of the width of the specimen in the thickness direction are not equal , i.e. the thickness of anisotropy index in the thickness direction of the change. This property , titanium axles known as the surface of the opposite sex in this sheet .
Actual measurements and calculations show that some two- thick titanium surface anisotropy index , its large difference of about 20% may be seen of this nature is sometimes the opposite sex can not be ignored .

2013年12月3日星期二

Localized corrosion and high temperature properties of titanium plate

1 , on the electrochemical properties of natural seawater temperature and localized corrosion properties of titanium alloys
Known from the cathodic polarization curve , high oxygen overpotential of titanium , which in general can not be an effective cathode. So that when in contact with other metals, titanium , alloys of accelerated corrosion B30 obvious titanium stockist, 18-8 to increase the corrosion rate is not significant . This can be confirmed from the results of galvanic current measured real sea, when it matches the titanium and titanium alloys resistant stainless steel use will not occur due to rapid acceleration of its electricity occasionally corrosion . This result and the early years of the Soviet Union and other scholars ToraWOB assertion and拉奎laboratory early match.
When the titanium potential is <-700mV (SCE) only when hydrogen absorption , so in our seawater tests have not found one who appears Schlain discussed phenomenon.
From the anodic polarization curve known until the release of oxygen , titanium is also undetectable in seawater break potential. Thus titanium does not appear in natural seawater pitting , crevice corrosion and stress corrosion cracking .
2 , localized corrosion properties of titanium on seawater temperature
As the seawater temperature, oxygen content reduced, resulting in titanium and other corrosion potential in the negative shift. Galvanic current value and the coupling thermal seawater corrosion rate of anode materials have shown a slight change in the condition of 80 ℃ thermal seawater titanium alloy and copper alloy, stainless steel and other corrosion resistant metal contact will not accelerate galvanic action such anode metal corrosion. Moreover, it is smaller than the real sea "dangerous ."titanium strip Temperature reported in the literature in hot titanium crevice corrosion in seawater were 93 ℃, 105 ℃, 110 ℃, 120 ℃, 130 ℃ , etc. , in our experimental conditions the results indicate the following 120 ℃, when no other external seawater when the impact of ions , pitting and crevice corrosion phenomena such localized corrosion will not occur.
Candle -resistant titanium reasons reported in the literature is due from the titanium surface is easy to form a highly complementary surface film , because studies have shown the work without making the mask , temporarily unable to report on whether the reader said .

2013年12月1日星期日

Chemical and physical properties of titanium and titanium plate

Commercially pure titanium by impurity elements in three levels, namely, TA1, TA2, TA3. Commercially pure titanium is mainly used for high plasticity, adequate strength, good corrosion resistance and weldability of the occasion. Their good cold workability,tittanium bars can produce a variety of plates, rods, profiles, strips, tubes and foil. Sheet can be cold stamping. Three grades of commercially pure titanium were annealed delivery use.
1 Chemical composition of commercially pure titanium
GB The TA1, TA2 and TA3 This corresponds UNS in Gr0, Gr1 and Gr2.
TA1, TA2 in ω is 0.095% iron, 0.08% oxygen content of ω, ω is a hydrogen content of 0.0009%, 0.0062% nitrogen content of ω, the low temperature toughness and has good high temperature strength, can be used -253 ℃ below the low temperature structural materials.
TA2 Chemical composition: TA2 titanium (Ti) the balance of iron (Fe) ≤ 0.30, carbon (C) ≤ 0.10, nitrogen (N) ≤ 0.05, the hydrogen (H) ≤ 0.015, oxygen (O) ≤ 0.25.
2 Physical and chemical properties of commercially pure titanium
Density: the density of 4.51, which is about 1/2 gold, 1/4, cobalt-chromium alloy.
Thermal conductivity is low: only gold 1/17, therefore, can effectively protect the titanium porcelain dental pulp tissue from the outside of the hot and cold acid stimulation;
Line shrinkage: 1.75%, lower than the gold alloy and cobalt-chromium alloy, has excellent suitability for casting high precision.
     Non-magnetic titanium:titanium stockists Titanium is not magnetized in a magnetic field.
Titanium metal surface passivation film has a strong resistance to corrosion: Titanium in the natural environment is almost not exist alone, it will react with oxygen to generate passive film on the surface of titanium dioxide, which has strong corrosion resistance.