Effect of Ca on microstructure and high temperature creep properties of AM60-1Ce alloy  

作　　者：Wei Jin Yu-lai Song Yao-hui Liu Ping Zhao R.D.K.Misra 

机构地区：[1]Key Laboratory of Automobile Materials (Ministry of Education), College of Materials Science and Engineering, Jilin University [2]College of Materials Science and Engineering, Qingdao University of Science & Technology [3]Department of Metallurgical, Materials and Biomedical Engineering, University of Texas

出　　处：《China Foundry》2019年第2期88-96,共9页中国铸造（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Grant No.50901035);the Science and Technology Development Projects of Jilin Province(Grant No.20140204042GX);the China Postdoctoral Science Foundation(Grant No.2018M642625)

摘　　要：A series of AM60-1Ce-xCa(x=0, 0.5, 1.5, 2.5) magnesium alloys were prepared by gravity casting method and analyzed by means of XRD, DSC and SEM. The effects of Ca on normal temperature mechanical properties and high temperature creep behavior of alloys were characterized by tensile and constant creep test.Microstructure analysis indicated that Ca was preferentially combined with Al in the alloy to form the high melting point Al_2Ca phase at the grain boundary. The addition of Ca can refine the crystal grains and reduces the content of β-Mg_(17)Al_(12) phase. With the increase of Ca content in the alloy, Al_2Ca phases at the grain boundary gradually changed to the network of lamellar structure, and replaced the β-Mg_(17)Al_(12) phase as the main strengthening phase gradually. The creep resistance of the alloy continuously increases because the high-temperature stable phase Al_2Ca firmly nailed at grain boundaries impedes the sliding of grain boundaries. However, when the addition of Ca was more than 1.5%, mechanical properties of the alloy started to decrease, which was probably due to the large amount of irregularly shaped Al_2Ca phases at the grain boundary. Experimental results show that the optimal addition amount of Ca is 1.5 wt.%.A series of AM60-1Ce-xCa(x=0, 0.5, 1.5, 2.5) magnesium alloys were prepared by gravity casting method and analyzed by means of XRD, DSC and SEM. The effects of Ca on normal temperature mechanical properties and high temperature creep behavior of alloys were characterized by tensile and constant creep test.Microstructure analysis indicated that Ca was preferentially combined with Al in the alloy to form the high melting point Al_2Ca phase at the grain boundary. The addition of Ca can refine the crystal grains and reduces the content of β-Mg_(17)Al_(12) phase. With the increase of Ca content in the alloy, Al_2Ca phases at the grain boundary gradually changed to the network of lamellar structure, and replaced the β-Mg_(17)Al_(12) phase as the main strengthening phase gradually. The creep resistance of the alloy continuously increases because the high-temperature stable phase Al_2Ca firmly nailed at grain boundaries impedes the sliding of grain boundaries. However, when the addition of Ca was more than 1.5%, mechanical properties of the alloy started to decrease, which was probably due to the large amount of irregularly shaped Al_2Ca phases at the grain boundary. Experimental results show that the optimal addition amount of Ca is 1.5 wt.%.

关 键 词：AS-CAST magnesium ALLOY Al2Ca HARD phase mechanical PROPERTIES high temperature CREEP PROPERTIES 

分 类 号：TG146.22[一般工业技术—材料科学与工程]