Different aging behaviors at surface layer and central region of a die-casting A380 alloy during heat treatment  

作　　者：Zi-hao Yuan Zhi-peng Guo Shou-mei Xiong 

机构地区：[1]School of CMaterials Science and Engineering, Tsinghua University, Beijing 100084, China [2]State Key Laboratory of Automobile Safety and Energy, Tsinghua University, Beijing 100084, China

出　　处：《China Foundry》2017年第6期506-512,共7页中国铸造（英文版）

基　　金：financially supported by the National Natural Science Foundation of China-China Aerospace Science and Technology Corporation Aerospace Advanced Manufacturing Technology Research Foundation(NO.U1537202);the Special Funding Program on Transformation of Scientific and Technological Achievements at Jiangsu Province(No.BA2015041)

摘　　要：Microstructural and hardness evolutions of a vacuum-assistant die-cast A380(Al-8.67 wt.%Si-3.27 wt.%Cu) alloy during heat treatment were investigated. Isothermal DSC test at 200 °C revealed that the precipitation reaction in the surface layer was faster than that in the central region. This corresponded with the hardness evolution that the surface layer hardened faster. The hardness increment in the surface layer was higher than that in the central region. Further experimental evidences indicated that the differences were due to the different amounts of heterogeneous nucleation sites for precipitation in the two parts. The influence of the characteristic as-cast microstructure on the artificial aging process is analyzed and discussed in detail.Microstructural and hardness evolutions of a vacuum-assistant die-cast A380（Al-8.67 wt.%Si-3.27 wt.%Cu） alloy during heat treatment were investigated. Isothermal DSC test at 200 °C revealed that the precipitation reaction in the surface layer was faster than that in the central region. This corresponded with the hardness evolution that the surface layer hardened faster. The hardness increment in the surface layer was higher than that in the central region. Further experimental evidences indicated that the differences were due to the different amounts of heterogeneous nucleation sites for precipitation in the two parts. The influence of the characteristic as-cast microstructure on the artificial aging process is analyzed and discussed in detail.

关 键 词：high pressure die casting(HPDC) heat treatment macro-segregation kinetics precipitation externally solidified crystals(ESCs) 

分 类 号：TG0[金属学及工艺]