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 e...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.展开更多
The evolution of microstructure and properties of Al−5.87Zn−2.07Mg−2.42Cu alloys during non-isothermal aging was studied.The mechanical properties of the alloy were tested by stretching at room temperature.The results...The evolution of microstructure and properties of Al−5.87Zn−2.07Mg−2.42Cu alloys during non-isothermal aging was studied.The mechanical properties of the alloy were tested by stretching at room temperature.The results show that in the non-isothermal aging process,when the alloy is cooled to 140℃,the ultimate tensile strength of the alloy reaches a maximum value of 582 MPa and the elongation is 11.9%.The microstructure was tested through a transmission electron microscope,and the experimental results show that the GP zones andη'phases are the main strengthening precipitates.At the cooling stage,when the temperature dropped to 180℃,the GP zones were precipitated again.Besides,the experimental results show that the main strengthening phase during non-isothermal aging isη'phases.展开更多
基金Project(2012CB619500)supported by the National Basic Research Program of ChinaProject supported by Yuying Project of Central South University
文摘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.
基金the National Key Research and Development Program of China(No.2018YFB2001801)the Postdoctoral Science Foundation of Central South University,China(No.220363)the National Natural Science Foundation of China(No.51601229).
文摘The evolution of microstructure and properties of Al−5.87Zn−2.07Mg−2.42Cu alloys during non-isothermal aging was studied.The mechanical properties of the alloy were tested by stretching at room temperature.The results show that in the non-isothermal aging process,when the alloy is cooled to 140℃,the ultimate tensile strength of the alloy reaches a maximum value of 582 MPa and the elongation is 11.9%.The microstructure was tested through a transmission electron microscope,and the experimental results show that the GP zones andη'phases are the main strengthening precipitates.At the cooling stage,when the temperature dropped to 180℃,the GP zones were precipitated again.Besides,the experimental results show that the main strengthening phase during non-isothermal aging isη'phases.
