摘要
The effect of homogenization time on quench sensitivity of a cast 7085 aluminum alloy was investigated by means of end-quenching test, optical microscope （OM）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that with the increase of homogenization time from 48 h to 384 h, quench sensitivity increased slightly as the largest difference in the hardness was increased from 5.2% to 6.9% in the end-quenched and aged specimens. Prolonging homogenization had little effect on the grain structure, but improved the dissolution of soluble T phase and resulted in larger Al3Zr dispersoids with a low number density. Some small quench-induced η phase particles on Al3Zr dispersoids were observed inside grains during slow quenching, which decreased hardness after subsequent aging. The change in the character of Al3Zr dispersoids exerted slight influence on quench sensitivity.
采用末端淬火实验、光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)研究均匀化时间对7085铝合金淬火敏感性的影响。结果表明,均匀化时间从48 h延长至384 h,淬火敏感性有所增加,端淬试样经人工时效后硬度的最大差值从5.2%增加到6.9%。均匀化时间延长对晶粒组织没有影响,但促使T相的溶解,增加Al3Zr弥散粒子的尺寸,减小其密度。慢速淬火时,在晶内的Al3Zr弥散粒子上能观察到一些尺寸较小的淬火析出η相,这降低了时效后的硬度。Al3Zr粒子特征的变化对淬火敏感性影响很小。
基金
Project(2012CB619500)supported by the National Basic Research Program of China
Project supported by Yuying Project of Central South University
