Effect of homogenization time on quench sensitivity of7085 aluminum alloy
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Guangxi Alnan Aluminum Inc., Nanning 530000, China;
3. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China)
2. Guangxi Alnan Aluminum Inc., Nanning 530000, China;
3. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China)
Abstract: 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.
Key words: 7085 aluminum alloy; homogenization; end quenching; quench sensitivity; Al3Zr dispersoids; equilibrium η phase