Effect of homogenization time on quench sensitivity of 7085 aluminum alloy

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.

均匀化前预处理对Al-4.3Zn-1.7Mg合金板材组织和性能的影响

采用光学显微镜、扫描电镜、透射电镜和常温拉伸等测试方法,研究均匀化工艺对Al-4.3Zn-1.7Mg合金板材显微组织和力学性能的影响。结果表明,经双级均匀化处理的Al-4.3Zn-1.7Mg合金铸锭,其热轧板经固溶时效处理后的强度及伸长率均高于经常规均匀化处理的合金热轧板的强度和伸长率。铸锭预处理温度从250℃升高至400℃,合金板材的强度及伸长率呈下降趋势,预处理时间从4 h延长至24 h,合金板材的强度呈现出先下降后上升的趋势,而伸长率无明显变化。