Microstructure and Mechanical Properties

of Titanium Alloys

Microstructure of Titanium Alloys

Titanium alloys have a variety of hot working processes and have very complex phase changes. There are many types of organizations, including dual-state organization, three-state organization, equiaxed organization, basket weft organization and Widmanstatten organization. Different microstructures will have different mechanical properties, and the organization determines the performance.

Mechanical Properties of Titanium Alloys

Iodide titanium, which can be deformed by 90% at room temperature, has good plasticity. No brittle fracture occurs at around 77K, and the notched specimens of impact processing. The elongation and cross-sectional shrinkage of iodide titanium increase with increasing temperature, and the tensile strength and yield strength decrease with increasing temperature.

The impurity elements N, O, and C of titanium are arranged in order from large to small, which can increase the tensile strength of titanium and reduce its plasticity. In titanium alloys with H content of 0.012~0.015% (wt.%), the impact of the mechanical properties of the specimens decreases sharply, and its notch sensitivity increases greatly, resulting in the so-called "hydrogen embrittlement".

In addition to the above elements, the influence of seven common elements on the strength of titanium, from strong to weak, are Cr, Co, Nb, Mn, Fe, V, and Sn, which can also improve the strength of titanium alloys.

Compared with aluminum and magnesium alloys, its strength is higher than that of many alloy steels. The strength of titanium alloys is about 5 times that of magnesium alloys and more than 2 times that of aluminum.

However, the change of titanium alloys is very small, and the strength of magnesium and aluminum alloys at 673K ​​is greatly reduced compared with that at room temperature. The elastic coefficient of titanium alloys is about more than one times that of steel.

The tensile strength of ordinary titanium alloys is 280MPa~1100MPa, which is the highest specific strength of titanium alloys among all metal materials currently used. The tensile strength can reach 1270MPa~1480MPa of high-strength titanium alloys.