激光堆焊Cr MnFeCoNi高熵合金组织与力学性能研究

Microstructures and mechanical properties of CrMnFeCoNi high-entropy alloy prepared by laser surfacing

  • 摘要: 采用激光堆焊技术在Q235钢上制备了成型良好的CrMnFeCoNi堆焊层,通过XRD,OM,SEM和EDS等分析手段研究了堆焊层的物相结构、微观组织和化学成分;通过硬度测试和拉伸测试表征了堆焊层的力学性能。结果表明,堆焊层内形成了呈树枝晶形貌的FCC单相固溶体。堆焊层内元素分布较均匀,但在枝晶内外存在细微的元素差异,Cr,Fe和Co富集在枝晶内部,Mn和Ni在树枝晶间偏析。堆焊层的硬度由表面至底部缓慢递减,约为180~200 HV0.5。堆焊层的拉伸性能有较强的温度依赖性,当温度从298 K降至77 K时,堆焊层的屈服强度和抗拉强度分别提升了60%和65%,达到了564 MPa和891 MPa,断后伸长率从26%提升到了36%。

     

    Abstract: A well-formed CrMnFeCoNi surfaced layer was prepared by laser surfacing technology on Q235 steel. The phase,microstructure and chemical composition were studied by XRD,OM,SEM and EDS,while the mechanical properties were investigated by hardness and tensile tests. The results indicated that a FCC single solution phase with dentrite morphology formed in the surfacing layer. The alloying elements were homogeneously distributed,but slight elements differences existed between dendrite and interdendrite. Cr/Fe/Co gathered in the dendrite while Mn/Ni segregated in the interdendrite. The microhardness of the coating is 180 ~ 200 HV0. 5 or so,which slowly decreased from the surface to the bottom. The tensile properties were dependent on the temperature. The yield strength and ultimate tensile strength increased by ~60% and ~ 65% to 564 MPa and 891 MPa,respectively,while ductility increased from 26% to 36% with a decrease of temperature from 298K to 77 K.

     

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