退火制度对钎焊用热轧复合铝板组织与性能的影响

Influence of Annealing on Microstructure and Mechanical Properties for Hot-rolled Aluminium Composite Brazing Sheet

采用金相显微镜、扫描电镜、透射电镜、X射线衍射仪、拉伸试验机、硬度计等研究了4343/3003/4343铝合金轧制复合板在100~500℃退火15min^10h后的微观组织和力学性能。结果表明:芯层合金300℃退火1h后开始再结晶,370℃以上退火1h后已完全再结晶且伴随有弥散相析出,弥散相析出后通过钉扎晶界阻碍再结晶晶粒长大;1h退火时,随退火温度升高,芯层合金晶粒先增大后减小,复合板的拉伸强度与硬度先降低后升高;370℃退火时,随退火时间延长,芯层合金再结晶程度增加,晶粒缓慢长大,复合板的拉伸强度与硬度下降;复合板最佳退火工艺为370℃/1h。

The microstructure and mechanical properties of 4343/3003/4343 hot-rolled aluminium com- posite sheet after annealing at 100-500℃ and 15min-10h were investigated by optical microscope, scan- ning electron microscope, transmission electron microscope, X-ray diffractometer, tensile testing ma- chine and hardness tester. The results show that recrystallization of the core alloy occurs at 300℃ for lh, which is accomplished above 370℃ with amounts of dispersoids precipitation. The dispersoids retard the recrystallized grain growth by pinning grain boundary. With increasing of annealing tempera- ture for lh, the grain size of the core alloy firstly increases and then decreases, and the tensile strength and hardness of the sheet vary conversely. Meanwhile, with annealing time at 370℃, the volume fraction of recrystallization for the core alloy increases and grain size grows gradually, and the tensile strength and hardness of the sheet decrease. The optimum annealing treatment for the sheet is 370℃/lh.