In order to measure the
fracture toughness of Ti-Al-Zr alloy forging of low-strength and high-toughness, this report firstly
tries to get the value of KIC by testing the compact tensile sample according to GB 4161-84 Standard Test Method for Plane-strain Tracture Toughness of Metallic Materials. Tth test found that the sample is in the apparent situation of plane stress. After analyzing the reason, we test the value of the crack tip opening displace (COD) of every sample using multiple samples according to GB/T 2358-1994 Test Method for Crack-tip Opening Displacement Measurement of Metallic Materials. A resis-tance curves(δR curves) and the equation of the curves are obtained by processing the data of six effective samples. Then crack-tip opening displacement of initial crack points (0=Da) and
fracture toughness KIC of such
titanium alloy are calculated. After SEM analysis of crack samples, various factors influencing the fracture toughness of Ti-Al-Zr alloy was discussed, and an approach to improve the fracture toughness of such titanium alloy was presented.