Influence of Mo content on microstructure and mechanical properties of β-containing TiAl alloy

Mo含量对含β相TiAl合金组织和力学性能的影响（英文）

The influence of Mo content on the microstructure and mechanical properties of the Ti?45Al?5Nb?xMo?0.3Y(x=0.6,0.8,1.0,1.2)alloys was studied using small ingots produced by non-consumable electrode argon arc melting.The results show that smallquantities ofβphase are distributed alongγ/α2lamellar colony boundaries as discontinuous network in the TiAl alloys owing to thesegregation of Mo element.Theγphase forms in the interdentritic microsegregation area when the Mo addition exceeds0.8%.Theβandγphases can be eliminated effectively by subsequent homogenization heat treatment at the temperature above Tα.The evolutionof the strength,microhardness and ductility at different Mo contents under as-cast and as-homogenization treated conditions wasanalyzed,indicating that excessive Mo addition is prone to cause the microsegregation,thus decreasing the strength andmicrohardness obviously,which can be improved effectively by subsequent homogenization heat treatment.

采用非自耗真空电弧熔炼Ti-45Al-5Nb-xMo-0.3Y(x=0.6,0.8,1.0,1.2)合金试样,研究Mo含量变化对含β相TiAl合金显微组织和力学性能的影响规律。研究表明,Mo元素的偏聚使β相呈不连续网状分布于γ/α_2片层团边界。当Mo含量超过0.8%时,β相在枝晶间微偏析区易形成γ相。在T_α转变温度以上进行均匀化热处理可使β和γ相得到有效消除。对初始铸态和均匀化热处理态TiAl合金的组织性能进行对比分析发现,添加过量的Mo元素容易引起微偏聚,从而降低材料的强度和显微硬度,而均匀化热处理可使得其力学性能得到明显改善。