Ta含量对Ti48Al2Cr2Nb合金组织与力学性能的影响OA

Ti48Al2Cr2NbxTa(x=0,1,2,4,atomic fraction/％)alloys were prepared by vacuum non-consumable arc melting,and the influence of Ta content on microstructural evolution and mechanical properties of the alloys was investigated.The results show that the alloy without Ta exhibits a coarse lamellar microstructure.As the Ta content increases,the microstructure is gradually refined and the precipitated phases become denser.The as-cast alloys are primarily composed of γ-TiAl and α2-Ti3Al phases.When the Ta content is 2％,the precipitated phases increase significantly,and the alloy shows a clear network and cellular structure with the best uniformity.With the increase of Ta content,the alloy hardness follows a trend of first increasing,then decreasing,and finally increasing.The 2％Ta alloy has a lower hardness and the highest compressive strength and ductility at both room and high temperatures.All alloys show brittle fracture at room temperature compression,and the 2％Ta alloy exhibits superior crack propagation resistance.