铝合金挤压件表层粗晶粒趋于长大这一事实在很久以时就被人们所了解,关于它们的形成原因和可能的控制方法也进行了多方面的研究。在各种因素之中,注意力集中在用添加合金元素的方法来影响或控制不利的粗晶再结晶过程的产生。近来,西德就这一问题,利用一种具有明显粗晶现象的Al-Cu-Mg合金挤压 The fact that the coarse grains of the surface layer of aluminum alloy extrusions tend to grow is well known for a long time and various aspects of their formation and possible control methods have also been studied. Among various factors, attention is focused on the method of adding alloying elements to influence or control the occurrence of unfavorable coarse recrystallization. Recently, West Germany on the issue, the use of a significant coarse grain Al-Cu-Mg alloy extrusion