W含量对镍基合金显微组织和高温抗拉强度的影响

Effect of W Content on Microstructure and High Temperature Tensile Properties of High Tungsten Cast Superalloy

对不同W含量的镍基高温合金的显微组织和1 100℃的抗拉强度进行了对比研究。结果表明,随着W含量的增加,合金次生γ′相形貌由规则的方块状聚集长大为不规则形状,体积分数由51.1%先增加至61.8%后下降至55.3%,在1 100℃的抗拉强度从405MPa先增至488MPa后降至433MPa。低W含量合金由于次生γ′相的体积分数较少而具有较低的高温抗拉强度,高W含量合金高温抗拉强度下降的主要原因是析出的α(W)相引起的次生γ′相的体积分数的下降。W含量为13.0%和15.5%的合金在1 100℃具有较高的抗拉强度,达440~488 MPa。

The microstructure and tensile strength at 1 100 ℃ of high W cast superalloy with W content of 12.0%,13.0%,15.5% and 16.5%（mass fraction）were investigated.The results show that with the increase of W content,the secondaryγ′phase is grown up into irregular shapes from regular square shape,and volume fraction is increased from 51.1%to 61.8%firstly and then decreased to 55.3%.The high temperature strength at 1 100℃of the superalloy is increased from 405 MPa to 488 MPa firstly and then decreased to 433 MPa.The alloy with low W content exhibits low tensile strength,which is mainly attributed to insufficient reinforcement of secondaryγ′phase,while for high W content superalloy,decrease of strength is attributed to the precipitation ofα（W）induced insufficient reinforcement of secondaryγ′phase.The tensile strength of alloys with W content of 13.0% and 15.5% has a higher strength,which reach 440~488 MPa at 1 100 ℃.