Eztrusion Press Quenching of a DC Cast Al-12.7Si-0.7Mg Alloy
Extrusion press quenching of the precipitation hardening Al alloys is capable of replacing the traditional solution treatment process in the T4 and T6 treatment. To this end, the effects of preheating temperature and holding time as well as the extrusion temperature on the microstructure evolution prior to extrusion should be investigated to insure the totally dissolving of the precipitation-forming elements. In this work, direct chill (DC) casting of an Al-12.7Si-0.7Mg alloy without chemical modification was performed. The microstructure of the cast alloy solution-treated at 500℃ for different time was investigated. We show that the as-cast microstructure consists of fully developed Al dendrites and the fine eutectics among the dendrites with the major intermetallic phase of Mg2Si and Al8FeMg3Si6. Upon preheating, spheroidization of the eutectic silicon phase was observed and the Si particles became coarser and rounder with time while the Al dendrites remain unchanged. The Mg2Si phase formed in the DC casting dissolved after 1.5 hour at 500 ℃ and the Al8FeMg3Si6 remain unchanged. We further show that extrusion press quenching of Al-12.7Si-0.7Mg alloy is capable of generating microstructures equivalent to that processed by solution treatment.
Al-Si alloy DC cast solution treatment microstructure eztrusion press quenching
LIU Fang YU Fu-xiao LIU Jie HONG Tao MA Bing ZUO Liang
Key Lab.for Anisolropy and Texture of Materials (Ministry of Education) Key Lab.of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Xinjiang Joinworld CO.,LTD,NO.18 East Kashgar Road,Urumqi 830013,China
国际会议
The Fourth Asian Conference on Heat Treatment and Surface Engineering(第四届亚洲热处理及表面工程大会)
北京
英文
272-276
2009-10-27（万方平台首次上网日期，不代表论文的发表时间）