金属型铸造Fe_3Al金属间化合物的组织和力学性能  

Microstructure and Properties of Fe_3Al Alloy Solidified in Permanent Mould

作　　者：李亚敏[1] 刘洪军[1] 谢斌[2] 郝远[1] 

机构地区：[1]兰州理工大学有色金属合金及加工教育部重点实验室,甘肃兰州730050 [2]兰州理工大学材料科学与工程学院,甘肃兰州730050

出　　处：《材料科学与工程学报》2010年第2期175-180,共6页Journal of Materials Science and Engineering

基　　金：甘肃省自然科学基金资助项目(3ZS042-B25-028);兰州理工大学有色金属合金及加工教育部重点实验室开放基金资助项目(EKL07009)

摘　　要：研究了中频感应炉熔炼、金属型冷却制备的Fe3Al铸态及热处理后的组织、力学性能和冲击断裂行为。结果表明:合金的铸态组织为等轴晶,平均晶粒尺寸约为100μm左右;合金经1000℃,15h均匀化退火+炉冷+600℃,1h中温回火+油淬热处理后,晶界得到了细化,晶内和晶界上析出了弥散分布的第二相,合金晶粒尺寸有所长大;XRD及EPMA点扫描分析综合得出弥散相的主要成分为Fe2AlCr,基体主要相组成为Fe2AlCr、Fe3Al、FeAl,晶界处主要相组成为Fe2AlCr和FeCr;热处理后合金的σb提高了46MPa,HRC由铸态时的22.5提高到了26.8,但合金的冲击韧性有所下降;铸态时合金的断裂方式主要以沿晶断裂为主,热处理后合金断口呈沿晶+穿晶的混合型断裂特征。Fe3Al alloy was prepared in a medium frequency induction furnace and solidified in a permanent mould.The microstructure,mechanical properties and impact fracture of Fe3Al alloy were studied.The microstructure of the as-cast alloy was characterized by equiaxed grains with an average grain size of about 100μm.After having been heat treated（1000℃/15h homogenizing annealing ＋ furnace cooling ＋ 600℃/1h tempering ＋ oil quenching）,the grain boundaries were refined and the grain size increased.The dispersive second phase was precipitated within the grains and on the grain boundaries.The results of XRD and EPMA show that：the dispersive phase is mostly Fe2AlCr;the matrix phase is composed of Fe2AlCr,Fe3Al and FeAl,and the grain boundary phases are Fe2AlCr and FeCr.Due to the heat treatment,the tensile strength of the alloy increases by 46 MPa and the hardness increases slightly,but the impact toughness decreases.The impact fracture transforms from intercrystalline fracture to intercrystallin ＋ transcrystalline mixed fracture after the heat treatment.

关 键 词：FE3AL 组织 力学性能 冲击断口 金属型 

分 类 号：TG27[金属学及工艺—铸造]