热处理对Al-Zn-Mg-Cu合金第二相粒子分布和晶粒尺寸的影响

Influence of intermediate heat treatment on distribution of second phase particles and grain size of Al-Zn-Mg-Cu alloy

通过对均匀化改锻后的坯料进行了固溶+过时效和直接过时效的中间热处理,分析了新型Al-Zn-Mg-Cu高强铝合金经过不同中间热处理后微观组织中第二相粒子的大小和分布特征,以及第二相粒子分布特征对随后热变形和退火工序过程中晶粒尺寸演变的影响。结果表明,锻坯经过400℃×12 h直接过时效中间处理后,组织中第二相粒子的尺寸呈现"双峰"分布特征;把具有该组织特征的试样加热到420℃的始锻温度,进行50%的压缩变形,再经400℃×1 h退火处理后,得到比较均匀细小的晶粒组织。

The size and distribution characteristics of second phase particles of Al-Zn-Mg-Cu high-strength aluminum alloy after different intermediate heat treatment were studied .The influence of second phase particles on grain size evolution during subsequent hot deformation and annealing processes was analyzed .The results show that the bimodal distribution characteristic of second phase particles can be obtained by the intermediate treatment process of 400℃×12 h over-aging process;and uniform and fine grains can be obtained by 50%compressive deformed at 420 ℃and annealed at 400 ℃for 1 h.