(北京有色金属研究总院,北京 100088)
摘 要: 采用Gleeble1500D热模拟实验机按设计的轧制工艺对7050合金进行压缩试验,模拟其多道次热轧过程,采用光学金相显微镜和透射电镜研究不同冷却条件下变形量为80%时试样的显微组织。结果表明:在热压缩过程中,合金未发生明显动态再结晶;合金在压缩后缓冷过程中发生静态再结晶,晶界形核和亚晶合并长大为其主要形核机制;合金中的Al3Zr粒子会阻碍晶界和亚晶界的移动,从而抑制再结晶和再结晶后的晶粒长大。
关键字: 7050铝合金;再结晶;形核机制;第二相
(General Research Institute for Nonferrous Metals, Beijing 100088, China)
Abstract:Hot compression tests of 7050 aluminum alloy was carried out on Gleeble1500D thermo-mechanical simulator according to the designed rolling processes to simulate the multi-pass hot rolling process. The microstructural features of the samples deformed to a reduction of 80% under different cooling conditions were investigated by OM and TEM. The results show that the dynamic recrystallization is not activated during the hot compression process, however, static recrystallization takes place during slow cooling after hot compression in which the main nucleation mechanisms are strain induced grain boundary migration(SIBM) and sub-grain coalescence and growth. The migration of grain and sub-grain boundaries can be retarded by the Al3Zr particles in the alloy, therefore, recrystallization process and grain growth after recrystallization process are restrained.
Key words: 7050 aluminum alloy; recrystallization; nucleation mechanism; second phase