对比研究了直接时效和双重时效对Ti-10V-2Fe-3Al合金微观组织及力学性能的影响。结果显示,在相同的时效时间下,双重时效后试样的屈服强度略低于直接时效,但双重时效的延伸率远远高于直接时效。较之直接时效,双重时效具有更好的强度塑性匹配。断口分析表明,直接时效断口为沿晶断裂,高倍形貌显示为晶界延性断裂。而双重时效断口以穿晶韧窝为主。微观组织观察表明,双重时效良好的强度塑性匹配源于α/β相间的片层组织,晶界α相薄膜的抑制及时效后初始β晶界、晶内组织之间强度差的减少。
The influence of simplex aging and duplex aging on the microstructures and mechanical properties of Ti-10V-2Fe-3Al (Ti1023) alloys were investigated. Results show that for the same aging time, yield strength of duplex aged samples is slightly lower than that of simplex aged samples. However, elongation of duplex aged samples is significantly higher than that of simplex aged ones. Compared with the simplex aged samples, the better combination of strength and ductility occurs in duplex aged ones. SEM fractography of simplex aged samples shows intergranular fracture mode at lower magnification but grain boundary ductile fracture at higher magnification. However, for duplex aged samples, transgranular dimple fracture is dominant. Microstructure observations show that the good combination of strength and ductility of duplex aged samples is attributed to the microstructure of alternately arranged α/β plates, the suppression of continuous grain boundary α film and the decreased strength difference between the β aged matrix and the β grain boundary precipitate zone.