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以Al-Cu-Li-Zr-Ce合金为研究对象,采用半定量分析统计方法,研究其断裂韧性机制,重点讨论时效时间和裂尖应力状态对合金分层开裂机制的影响。结果表明:随时效时间延长,起始区分层开裂特征所占比例越大,韧窝比例越小,甚至出现准解理特征;稳态扩展区,分层开裂为主要开裂机制;近失稳扩展区,分层比例下降,准解理逐渐成为主要断裂特征。随时效时间延长和裂纹扩展,分层厚度减小。分层裂纹的产生及扩展与主裂纹扩展及合金的时效时间有密切的关系。断裂韧性试样断口上分层比例较高时,合金可以获得较高的强度,同时保持相对较高的韧性。
Taking Al-Cu-Li-Zr-Ce alloy as the research object, the semi-quantitative analysis method was used to study the fracture toughness mechanism. The effects of aging time and crack tip stress on the delamination cracking mechanism were discussed. The results show that with the aging time prolonging, the proportion of delamination cracking in the initial zone is larger, the proportion of dimples is smaller, and even quasi-cleavage characteristics appear. The steady-state extension zone and delamination cracking are the main cracking mechanisms and the near-instability Expansion zone, stratification decreased, quasi-cleavage has gradually become the main fault characteristics. With the aging time and crack growth, delamination thickness decreases. The generation and propagation of delamination cracks are closely related to the propagation of the main crack and the aging time of the alloy. Fracture toughness specimen fractures layered higher proportion, the alloy can obtain higher strength, while maintaining a relatively high toughness.