摘要
Fe3Al alloys with nearly full density were fabricated by plasma activated sintering（PAS） and hot pressing（HP） from mechanical alloyed Fe-28%Al（mole fraction） powders,respectively.It is found that A2-type Fe3Al alloys were obtained by PAS,and they had a heterogeneous grain size distribution,most areas had a grain size smaller than 500 nm,and other areas had a grain size of about 1 μm.Different to PAS,D03-type Fe3Al alloys with a grain size of of 1-2 μm were obtained by HP.The compression testing results show that yield strength values of Fe3Al alloys fabricated by PAS and HP are almost equal at an elevated temperature,and the compression yield strength was about 100 MPa for all at 800 ℃.The room temperature compression ductility of Fe3Al alloys by PAS was about 20%,which was superior to that of Fe3Al alloys prepared by HP and casting.
以机械合金化Fe-28%Al(摩尔分数)合金粉末为原料,分别采用等离子活化烧结(PAS)和热压烧结(HP)方法制备致密度高达99%的Fe3Al金属间化合物。XRD和TEM测试结果表明:PAS烧结试样保留了机械合金化粉末的A2无序结构,并呈现出亚微米晶粒区域(>1μm)和纳米晶粒区域(<500nm)双峰分布的特征,而HP烧结试样为部分D03有序结构,晶粒尺寸在1～2μm的范围内。压缩试验表明:在室温至800℃的条件下,采用两种方法烧结的Fe3Al金属间化合物具有近似的压缩强度,虽然当温度超过400℃后压缩屈服强度均急剧下降,但在800℃时其压缩屈服强度仍高达100MPa,远高于铸造态Fe3Al金属间化合物。相比于HP烧结和铸造态Fe3Al金属间化合物,PAS烧结Fe3Al金属间化合物表现出优异的室温塑性,其室温压缩工程应变为20%。组织结构分析和力学性能测试结果表明,超细晶无序组织有利于Fe3Al金属间化合物室温塑性和高温强度的同时增强。
基金
Project (50871084) supported by the National Natural Science Foundation of China
Project (2009AA032601) supported by the National High Technology Research and Development Program of China
