Investigation on Homogenization Process of Large Size of Al-Zn-Mg-CuAluminum Alloy Ingot
CHAO Daiyi1,2, LI Changlong1,2, ZHAO Jialei1,2, SUN Youzheng1,2,ZHAO Zhiguo1,2, HUO Yan1, LYU Zhengfeng1,2
1 Shandong Nanshan Aluminum Co., Ltd., Longkou 265713, China; 2 National Engineering Research Center for Plastic Working of Aluminium Alloys, Longkou 265713, China
Abstract: In order to solve the homogenization issues of the large size Al-Zn-Mg-Cu alloy ingot, the effect of homogenization process on the microstructure and over-burning of Al-Zn-Mg-Cu alloy large ingot was studied by using OM, DSC, SEM and TEM analysis methods. The results showed that: a large number of dispersed Al3Zr phase was precipitated in the matrix after homogenized at 420 ℃ for 4 h, while the ingot was over-burned after increasing the temperature up to 475 ℃. After the alloy was homogenized at 470 ℃/8 h, the peak of the low melting point of the alloy moved to the high temperature direction, the dendritic structure in the alloy basically disappeared, and the Zn-rich and Mg-rich phases disappeared, the EDS test showed that the alloy mainly consisted of Cu-rich, Mg-rich and Cu-rich and Fe phases, and the over-burning temperature reached 480 ℃. In order to further reduce the influence of Cu-rich and Mg-rich phases, the temperature was further increased to 478 ℃ on the basis of 470 ℃ homogenization, no over-burning was found and the content of the second phase was further reduced. In this paper, the homogenization tempe-rature of Al-Zn-Mg-Cu alloy large ingots was determined to be 420 ℃/4 h+470 ℃/8 h+478 ℃/12 h, at this time the ingot had no over-burned and the second phase content decreased obviously.
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