循环应变-高温退火制备Al-Cu-Li合金单晶

Preparation of Al-Cu-Li alloy single crystal by cyclic strain-high temperature annealing

通过循环预拉伸应变-高温退火制备Al-Cu-Li合金单晶,同时探讨循环预拉伸应变-高温退火过程中预拉伸应变量、循环应变退火次数、应变退火温度对Al-Cu-Li合金晶粒长大的影响以及晶粒长大的过程与机制。研究结果表明,通过循环预拉伸应变退火可以使得合金晶粒异常长大,并且成功制备出厘米级别的宏观粗大晶粒,其长大机理主要为应变诱导晶界迁移(Strain-Induced Boundary Migration)形核再结晶异常晶粒长大。此外,分别对Al-Cu-Li合金预拉伸应变量、循环应变退火次数以及应变退火温度对晶粒长大影响进行研究,制定出较优的单晶制备工艺,结果表明较优工艺为AlCu-Li合金经0.8%预拉伸应变后在540℃下退火48 h,循环次数2~3次。

Al-Cu-Li alloy single crystals were prepared by cyclic pre-tensile strain-high temperature annealing.The paper discussed the effects of tensile strain,number of cyclic strain annealing,and strain annealing temperature on grain growth of Al-Cu-Li alloy and the process and mechanism of grain growth during cyclic pre-tensile strain-high temperature annealing.The research results showed that the alloy grains could grow abnormally through cyclic pre-tension strain annealing,and the centimeter-level macro coarse grains were successfully prepared.Their growth mechanism was mainly nucleation recrystallization abnormal grain growth by strain-induced grain boundary migration.In addition,studying the effects of the pre-stretching strain of Al-Cu-Li alloy,the number of cyclic strain annealing and the temperature of strain annealing on the grain growth was quite helpful to develop the best single crystal preparation.The results showed that the optimal process of the Al-Cu-Li alloy was annealed at 540°C for 48 h after pre-tensioned strain of about 0.8%,with cycle number 2 to 3 times.