Alloying elements according to their impact on the phase transition temperature can be divided into three categories

① stable α phase, phase transformation element is α stabilizing element, aluminum, carbon, oxygen and nitrogen. Wherein the aluminum alloy is the main alloying elements, and its improved high-temperature strength of the alloy at room temperature, reduce the proportion, significantly increase effective elastic modulus

② stable β phase, the phase transition temperature of the lower element of β stabilizing element, can be divided into the same crystal type and eutectoid two. Application of titanium alloy plate products
The former molybdenum, niobium, vanadium; the latter are chromium, manganese, copper, iron, and silicon.
③ small element of the phase transition temperature of the neutral element, zirconium and tin.
Oxygen, nitrogen, carbon and hydrogen are the main impurities of titanium. Oxygen and nitrogen in the α phase has a greater solubility of medical titanium plate  significant strengthening effect but the plastic drop. Usually it provides the titanium content of oxygen and nitrogen in the 0.15 to 0.2% and 0.04% to 0.05% or less, respectively. The solubility of hydrogen in the α phase is very small, titanium dissolved hydrogen will produce excess hydride, the alloy becomes brittle. Titanium usually hydrogen content control 0.015%. Hydrogen was dissolved in titanium is reversible, can be removed by vacuum annealing.