Formation of TiAlSi intermetallics during heating Ti-A356 Al mixed powder compact at semisolid temperature  

作　　者：M.Gao T.J.Chen Z.X.Zhang 

机构地区：[1]State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China

出　　处：《Journal of Materials Science & Technology》2021年第35期247-263,共17页材料科学技术（英文版）

基　　金：supported by the National Key Research and Development Program(grant No.2018YFB2001800);the National Natural Science Foundation of China(grant No.51564035)。

摘　　要：Due to the similarity in composition and crystal structure of some Ti Al Si ternary intermetallics,it is quite difficult to accurately confirm their physic characteristics,and thus,to tailor microstructure to improve mechanical properties of metal materials related to the Ti Al Si intermetallics.Therefore,the formation process of Ti Al Si intermetallics was investigated during heating Ti-A356 mixed powder compact at a A356 alloy semisolid temperature of 595℃.The results indicated that two kinds of intermetallics ofτ1(tetragonal,I41/amd)andτ2(orthorhombic,Cmcm)generated,and both the concentration and supply direction of Ti atoms,which are related to local breakage of oxide films on neighboring Ti and A356 alloy powders,determined the phase and morphology of the intermetallics.τ1 andτ2 crystals all had an intrinsic plate morphology,butτ2 crystals were thinner due to more anisotropic growth resulted from their high density of stacking faults(SFs).τ1 lamellar domains generated during growth ofτ2 crystals,which were accompanied by decrease in density of SFs.The combined effect of size difference and internal energy difference betweenτ1 andτ2 crystals made largeτ1 crystals coarsen at the expense ofτ2 crystals in Ostwald ripening,leading them to finally evolve into an agglomerate of largeτ1 plates.

关 键 词：INTERMETALLICS Stacking faults Growth Phase transformation 

分 类 号：TG146.23[一般工业技术—材料科学与工程]