There are two isomeric titanium crystals surgical implant titanium

Titanium is a titanium- based alloy by adding other elements
There are two isomeric titanium crystals : Below 882 ℃ for the close-packed hexagonal structure α titanium , titanium above 882 ℃ for the body-centered cubic β .surgical implant titanium  Alloying elements according to their effect on the phase transition temperature can be divided into three categories : ① stable α -phase , improving the phase transition temperature of the elements of α stabilizing element , aluminum , carbon, oxygen and nitrogen . Which aluminum is the main alloying elements titanium, improving its strength at room temperature and high temperature alloys , lower specific gravity, increased elastic modulus have a significant effect . ② stable β -phase, reducing the element of the phase transition temperature of β stabilizing element , and can be divided isomorphous and eutectoid two . The former molybdenum , niobium, vanadium, etc. ; latter chromium, manganese, copper, iron , and silicon. ③ small element of the phase transition temperature of the neutral elements , zirconium and tin .
Oxygen, nitrogen, medical titanium plate carbon and hydrogen are the main impurities of titanium . Oxygen and nitrogen in the α phase has a greater solubility of the titanium alloy has a significant strengthening effect , but the plastic drop. Typically provide oxygen and nitrogen content of titanium 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 in excess hydride hydrogen will produce the alloy brittle. Titanium is usually controlled hydrogen content of 0.015% or less. The hydrogen dissolved in the titanium is reversible , vacuum annealing can be removed .