均匀化升温速率对7N01 铝合金组织与力学性能的影响

曾世宝^1,2，叶凌英^1,2，刘胜胆^1,2，邬沛卿^1,2，单朝军^1,2，邓运来^1,2，张新明^1,2

(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)

摘 要：采用光学显微镜、扫描电镜、电子探针显微镜、透射电镜和常温拉伸等测试方法研究均匀化升温速率对7N01 铝合金显微组织和力学性能的影响。结果表明：与升温速率较快的均匀化制度相比，采用升温速率小于100℃/h 的慢速升温均匀化制度更有利于细小弥散Al3Zr 粒子的析出，使Al3Zr 粒子分布均匀；细小弥散的Al3Zr 粒子能有效地阻止再结晶晶界的迁移，抑制再结晶的发生。随着均匀化升温速率由500 ℃/h 降低到20 ℃/h，析出的Al3Zr 粒子数量增加，尺寸减小，析出相体积分数和半径的比值φ/r 由75.8 μm^-1 增大到359.1 μm^-1，使得Al3Zr粒子对晶界的钉扎力增大，因此合金的再结晶分数相应地由31.92%逐渐降低到1.32%；保留下来的大量位错和未再结晶组织提高了合金的综合力学性能。

关键词：7N01 铝合金；Al3Zr；均匀化；升温速率；再结晶；力学性能

Effect of homogenization heating rate on microstructure and mechanical properties of 7N01 aluminum alloy

ZENG Shi-bao^1,2,YE Ling-ying^1,2,LIU Sheng-dan^1,2,WU Pei-qing^1,2, SHAN Chao-jun^1,2,DENG Yun-lai^1,2,ZHANG Xin-ming^1,2

(1. School of Materials Science and Engineering,Central South University,Changsha 410083,China;
2. Key Laboratory of Nonferrous Materials Science and Engineering,Ministry of Education,
Central South University,Changsha 410083,China)

Abstract:The effects of homogenization heating rate on the microstructure and mechanical properties of 7N01 aluminum alloy were investigated by optical microscopy (OM),scanning electron microcopy (SEM),electron probe microanalyzer (EPMA),transmission electron microcopy (TEM) and tensile test. The results show that using a slow homogenization heating rate less than 100 ℃/h is favorable for the precipitation of fine and uniformly distributed Al3Zr particles compared with fast homogenization heating rate. The dispersion distribution of fine Al3Zr particles can decrease the recrystallized fraction since the Al3Zr particles can effectively prevent the migration of recrystallization grain boundary. When the homogenization heating rate decreases from 500 ℃/h to 20 ℃/h,the average dispersoid number increases,the particle size decreases,and the ratio of volume fraction (φ) to radius (r) of the precipitate (φ/r) increases from 75.8 μm^-1 to 359.1 μm^-1,which improves the dragging effect of Al3Zr particles on the grain boundaries and leads to a reduction in the recrystallized fraction from 31.92% to 1.32%. Meanwhile,the unrecrystallized microstructures containing profuse dislocations enhance the comprehensive mechanical properties of the studied alloy.

Key words:7N01 aluminum alloy; Al3Zr; homogenization; heating rate; recrystallization; mechanical property