摘要
Microstructure evolution and mechanical properties of the cast Mg-10Gd-3Y-1.2Zn-0.4Zr(mass fraction,%) alloy during annealing at 798 K for different time were investigated.In the as-cast state,the microstructure consists ofα-Mg,Mg_5(Gd,Y,Zn) eutectic compounds and stacking faults(SF) of basal plane distributed from grain boundary to inner grain.During heat treatment at 798 K,the SF and parts of eutectic compounds dissolve into the matrix gradually,simultaneously,a new straight lamellar phase with 14H type of long period stacking ordered(LPSO) structure comes into being.Microstructure observation indicates that the lamellar phase is transformed from the un-dissolved eutectic compounds and shows a coarsening and disappearing process with annealing time prolonging.Three alloy specimens with typical microstructure after being annealed for 6,36 and 72 h were selected to age at 498 K to peak hardness.Room and elevated temperature tensile tests show that the LPSO structured phase contributes to the change of high temperature tensile properties.
Microstructure evolution and mechanical properties of the cast Mg-10Gd-3Y-1.2Zn-0.4Zr （mass fraction, %） alloy during annealing at 798 K for different time were investigated. In the as-cast state, the microstructure consists of a-Mg, Mgs（Gd, Y, Zn） eutectic compounds and stacking faults（SF） of basal plane distributed from grain boundary to inner grain. During heat treatment at 798 K, the SF and parts of eutectic compounds dissolve into the matrix gradually, simultaneously, a new straight lamellar phase with 14H type of long period stacking ordered（LPSO） structure comes into being. Microstructure observation indicates that the lamellar phase is transformed from the un-dissolved eutectic compounds and shows a coarsening and disappearing process with annealing time prolonging. Three alloy specimens with typical microstructure after being annealed for 6, 36 and 72 h were selected to age at 498 K to peak hardness. Room and elevated temperature tensile tests show that the LPSO structured phase contributes to the change of high temperature tensile properties.
出处
《中国有色金属学会会刊：英文版》
CSCD
2008年第A01期117-121,共5页
Transactions of Nonferrous Metals Society of China
基金
Project(2007CB613701)supported by the National Basic Research Program of China
Project(08XD14020)supported by ShanghaiSubject Chief Scientist Program,China
