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研究了热处理制度对Ti-6Al-4V ELI钛合金厚板显微组织及力学性能尤其是损伤容限性能的影响。研究表明:板材经普通退火、α+β相区固溶时效处理后其显微组织呈网篮状,这种组织具有较高的拉伸性能,但抗疲劳裂纹扩展能力较差。而经β相区固溶时效处理后,得到的显微组织为具有粗大原始β晶粒的魏氏组织,这种组织的拉伸塑性较低,但具有较高的断裂韧性和较低的疲劳裂纹扩展速率。通过对疲劳裂纹扩展断口及扩展路径的观察,分析了厚板显微组织对疲劳裂纹扩展速率的影响。
The effects of heat treatment on the microstructure and mechanical properties of Ti-6Al-4V ELI titanium alloy plate, especially the damage tolerance performance, were studied. The results show that the microstructure of the plate is basket-like after normal annealing and α + β phase zone solution treatment. The microstructure of the plate has high tensile properties, but its fatigue crack growth resistance is poor. However, the microstructure after solution aging treatment in the β-phase zone is a Wistarian tissue with coarse primary β grains, which has low tensile ductility but high fracture toughness and low fatigue Crack propagation rate. By observing the propagation of fatigue crack propagation and propagation path, the effect of slab microstructure on fatigue crack growth rate was analyzed.