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针对低强度高塑性的Ti-Al-Zr钛合金锻材的断裂韧度的测定工作,先根据GB4161-84《金属材料平面应变断裂韧度试验方法》,尝试了采用紧凑拉伸试样直接测定其KIC值,但试验后发现样品呈明显的平面应力状态。分析原因后,根据GB/T 2358-94《金属材料裂纹尖端张开位移试验方法》采用多试样法,测定出各试样的裂纹尖端张开位移(COD)量。对从6个有效试样上获得的数据进行了处理,绘制出其δR阻力曲线,并拟合出阻力曲线方程。然后以启裂点(0=Da)的裂纹张开位移量作为δc,换算出这种钛合金的平面断裂韧度KIC值。对样品断口进行SEM分析后,探讨了影响断裂韧度的各种因素,并提出了提高这种钛合金材料断裂韧度的途径。
Aiming at the determination of fracture toughness of Ti-Al-Zr titanium alloy forging with low strength and high plasticity, according to GB4161-84 “Test method of plane strain fracture toughness of metal materials”, the direct determination of fracture toughness The KIC value, but after the test showed that the sample showed a significant plane stress state. After analyzing the reasons, the crack tip open displacement (COD) of each sample was measured according to GB / T 2358-94 “Test method for crack tip open displacement of metallic materials” by using a multi-sample method. The data obtained from the six valid samples were processed, their δR resistance curves were plotted, and the resistance curve equations were fitted. Then the crack opening displacement at the crack initiation point (0 = Da) is taken as δc, and the KIC value of the plane fracture toughness of the titanium alloy is calculated. After analyzing the fracture surface of the sample by SEM, the various factors that affect the fracture toughness were discussed and the ways to improve the fracture toughness of the titanium alloy were proposed.