What Are The Mechanical Properties Of Gr23 Medical Titanium Alloy?

Titanium alloys are widely used in the aerospace sector due to their high specific strength, light weight, high working temperature and excellent corrosion resistance. Currently, titanium alloys used in the aerospace sector account for about 70% of total titanium production. High purity titanium has excellent plasticity, but the impurity content exceeds a certain amount will form brittle compounds, the plasticity of titanium alloys drop sharply. The microstructure of titanium alloy is an important factor in determining its tensile strength, fatigue strength and cracking toughness. Its arrangement is mainly composed of α and β phases, and its arrangement shape can be divided into Weiss, mesh basket, bimodal and isometric arrangement.

(1) tensile function: generally in the original β grain boundaries scattered on the coarse α phase, and this coarse original β grain generally exists in the Weil's arrangement, and scattered in the direction of roughly parallel Weil's α bars. In general, the room temperature plasticity of the WEA is poor because of its coarse grains. The bimodal arrangement generally consists of relatively fine primordial α phase and β alteration arrangement , if the bimodal arrangement obtained through the "solid solution + aging" treatment , its room temperature tensile strength is a little stronger than the other three arrangements .

(2) Cracking toughness and crack extension rate : Generally speaking, the cracking toughness of the Weiss arrangement is greater than that of the equiaxial α-arrangement and bimodal arrangement. The cracking toughness of the alloy is greatly affected by the number and size of the incipient α-phase, and the cracking toughness increases with the reduction of the incipient α-phase.

(3) Fatigue function: Among the above four different types of arrangements, the fatigue limit of the isometric arrangement is very large, and the fatigue limit of the Weiss arrangement is very poor. Secondly, no matter low or high fatigue, for the same alloy, the fatigue performance of the bimodal arrangement is very good, while the fatigue performance of the Weil's arrangement is relatively poor.

(4) Thermal stability and creep resistance: the so-called heat-resistant titanium alloy is an alloy with excellent thermal stability. However, because the heat resistance of β-phase is not good, so in the heat-strengthened titanium alloys generally contain only a small amount of β-phase α-alloys and α + β-alloys. Creep resistance is mainly affected by the arrangement shape. Among the four arrangement forms, the isometric arrangement has a poor creep function due to the fine grain size and many interfaces; the Weiss organization has a high creep resistance, but its organization grain size is very coarse, and the α-phase at the grain boundaries is coarse and easily contaminated by oxygen, and there are also some weaknesses. Therefore, the application of titanium alloys at high temperatures generally choose the two-state arrangement and basket arrangement, with better induction, the primary α-phase is less.