Al和Mo含量对热等静压制备的FeCrAlMo合金组织及拉伸性能的影响

Effect of Al and Mo Content on the Microstructures and Tensile Property of FeCrAlMo Alloys

FeCrAl合金由于具有良好的高温抗氧化性能和力学性能而广泛应用于高温和氧化性气氛环境。本研究通过粉末热等静压制备出Fe-22Cr-3Al-3Mo和Fe-22Cr-2Al-5Mo两种成分的合金,对粉末的显微组织、热等静压后两种成分合金的组织及拉伸性能进行对比分析,结果表明:Fe-22Cr-3Al-3Mo合金20℃时的强度和塑性都高于Fe-22Cr-2Al-5Mo合金,而500℃时的强度和塑性都低于Fe-22Cr-2Al-5Mo合金;Fe-22Cr-3Al-3Mo合金中析出相主要为分布在晶界及晶内的细小AlN相及少量粗大的富Cr相,Fe-22Cr-2Al-5Mo合金中析出相主要为大尺寸的富Cr碳氧化物;Al含量降低、Mo含量增加,晶界形成较多的大尺寸富Cr相,导致Fe-22Cr-2Al-5Mo合金在20℃时塑性较差。

FeCrAl alloys were widely used in elevated temperature and oxidising environment due to its outstanding oxidation resistance and mechanical property at high temperature.Two FeCrAl alloys with different chemical composition,Fe-22Cr-3Al-3Mo and Fe-22Cr-2Al-5Mo,produced by hot isostatic pressing(HIP),were investigated in this paper.The microstructures of powders of two alloys were characterized.And the microstructures and tensile strength of as-HIP samples of two alloys were characterized and tested.The results showed that the tensile strength and plasticity of Fe-22Cr-3Al-3Mo alloy were both higher than Fe-22Cr-2Al-5Mo alloy at 20℃,but they were both lower than Fe-22Cr-2Al-5Mo alloy at 500℃.The precipitation in the Fe-22Cr-3Al-3Mo alloy were mainly fine AlN phase and a small amount of Cr-rich phase in the grains and grain boundaries.The precipitation in the Fe-22Cr-2Al-5Mo alloy was mainly large size oxycarbides of Cr-rich phase.With the decreasing of Al content and the increasing of Mo content,more large sized Cr-rich phases were precipitated in the grain boundaries,which resulted in the poor plasticity of Fe-22Cr-2Al-5Mo at 20℃.