锻压技术

高速冲击载荷下Ti6242钛合金的绝热剪切行为及裂纹扩展机理

英文标题：Adiabatic shear behavior and crack propagation mechanism on Ti6242 titanium alloy under high-speed impact loading

作者：彭德平刘筱贺丹丹万步炎陈阳刘文辉

单位：1.湖南科技大学机电工程学院 2.湘潭华进重装有限公司 3.湖南胜利湘钢钢管有限公司

分类号：TG389

出版年,卷(期):页码：2022,47(9):224-229

摘要：

为了研究Ti6242钛合金在不同冲击载荷下的绝热剪切行为和裂纹扩展机理，采用分离式Hopkinson Bar技术，在室温下对其进行冲击平均应变速率为3069~11337 s-1的冲击试验，使用光学显微镜对其微观组织中的绝热剪切行为进行分析，并建立了裂纹形核及扩展模型。结果表明：Ti6242钛合金的抗冲击强度对冲击平均应变速率不敏感，塑性随着冲击平均应变速率的增加呈现增加趋势；绝热剪切带的数量随着冲击平均应变速率的增加而增加，片层状分布的α/β相会阻碍绝热剪切带的扩展，导致绝热剪切带出现分叉现象；高速冲击载荷下，孔洞在绝热剪切带内形核、长大、合并，最终形成微裂纹，微裂纹通过与前端孔洞合并继续扩展而形成宏观裂纹，导致材料断裂失效。

In order to study the adiabatic shear behavior and crack propagation mechanism of Ti6242 titanium alloy under different impact loading, the impact test with average impact strain rate of 3069-11337 s-1 at room temperature was carried out by split Hopkinson Bar technique. Then, the adiabatic shear behavior in microstructure was analyzed by optical microscope, and the crack nucleation and propagation model was established. The results show that the impact strength of Ti6242 titanium alloy is not sensitive to average impact strain rate, and the plasticity displays an increasing trend with the increasing of the average impact strain rate. The number of adiabatic shear bands increases with the increasing of the average impact strain rate, and α/β phase in lamellar distribution hinders the propagation of adiabatic shear band, resulting in the bifurcation phenomenon of adiabatic shear bands. Under the high-speed impact loading, the pores nucleate, grow and merge in the adiabatic shear band, and finally form micro-cracks, which continue to expand by merging with the front-end holes to form macro-cracks, resulting in fracture failure of material.

基金项目：

国家自然科学基金资助项目(51905166，52071139)；湖南省教育厅优秀青年基金项目（21B0471）

彭德平（1987-），男，博士研究生 E-mail：eden7321@163.com 通信作者：刘筱（1988-），女，博士，副教授，博士生导师 E-mail：liuxiao0105@163.com

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