STUDY ON GRANULATION MECHANISMS OF γ+(Fe,Mn)3C EUTECTICS IN AUSTENITE STEEL COMPOSITES  

作　　者：G.F.Liang Z.M.Xu Q.C.Jiang J.G.Li 

机构地区：[1]SchoolofMaterialsScienceandTechnology,ShanghaiJiaotongUniversity,Shanghai200030,China [2]SchoolofMaterialsScience,JilinUniversity,Changchun130025,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2003年第6期449-456,共8页金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.50001008).

摘　　要：Results presented in this paper contribute to investigation of the granulation mechanisms of γ+(Fe,Mn)3C eutectics in the austenite matrix composites (abbreviated EAMC). The specimens corresponding to the nominal composition of eutectic with controlled RE(Ce)-Mg agent modifier additions have been unidirectional solidified with a constant growth rate of 2.18μm/s at a fixed temperature gradient of 800K/cm using vertical Bridgeman method. With the RE-Mg agent modifier, the transition of solid/liquid (S/L) interface from columnar to dendrite (CDT), refinement and developed branching of γ and (Fe,Mn)3C phases in the eutectics, and the transition of growth style from faceted-nonfaceted (F/NF) to nonfaceted-nonfaceted (NF/NF) for γ and (Fe,Mn)3C phases in the eutectic have been observed and investigated theoretically. Those can explain the granulation of γ+(Fe,Mn)3C eutectics in the as cast because the roundness increases with the developed lateral branching of primary austenite dendrites, refinement of eutectics, and NF/NF growth of γ and (Fe,Mn)3C phases in the eutectic.Results presented in this paper contribute to investigation of the granulation mechanisms of γ+(Fe,Mn)3C eutectics in the austenite matrix composites (abbreviated EAMC). The specimens corresponding to the nominal composition of eutectic with controlled RE(Ce)-Mg agent modifier additions have been unidirectional solidified with a constant growth rate of 2.18μm/s at a fixed temperature gradient of 800K/cm using vertical Bridgeman method. With the RE-Mg agent modifier, the transition of solid/liquid (S/L) interface from columnar to dendrite (CDT), refinement and developed branching of γ and (Fe,Mn)3C phases in the eutectics, and the transition of growth style from faceted-nonfaceted (F/NF) to nonfaceted-nonfaceted (NF/NF) for γ and (Fe,Mn)3C phases in the eutectic have been observed and investigated theoretically. Those can explain the granulation of γ+(Fe,Mn)3C eutectics in the as cast because the roundness increases with the developed lateral branching of primary austenite dendrites, refinement of eutectics, and NF/NF growth of γ and (Fe,Mn)3C phases in the eutectic.

关 键 词：composite RE-Mg agent GRANULATION unidirectional solidifica-tion 

分 类 号：TB331[一般工业技术—材料科学与工程] TG142.25[金属学及工艺—金属材料]