C元素对FGH96粉末高温合金显微组织和力学性能的影响

对C质量分数分别为0.05%和0.09%的FGH96合金进行了显微组织和力学性能的分析。结果发现:C元素含量较高时,除了碳化物数量明显增多外,还会在晶界处形成较大尺寸的块状MC碳化物;但是,C元素含量并未对原始颗粒边界(prior particle boundary,PPB)、晶粒度及γ′相产生明显的影响。C元素含量较高会提高FGH96合金在650℃时的抗拉强度和屈服强度,但会降低其塑性。在低周疲劳试验中,C元素含量较高,形成的大块MC型碳化物分布于表面或亚表面,将会作为裂纹起源从而显著降低合金的低周疲劳性能。

Effect of carbon content on the microstructure and mechanical properties of powder metallurgy superalloy FGH96

Effects of carbon content (0.05wt％ and 0.09wt％) on the microstructure and mechanical properties of powder metallurgy superalloy FGH96 were investigated in this paper.With the increase in C content,the number of carbide is increased obviously,and a few larger blocky MC-type carbides appear at the grain boundaries.Furthermore,there is little effect of C content on prior particle boundary (PPB),grain size,and γ'precipitates.With the increase in C content,the tensile strength and yield strength of FGH96 alloy increase,but the plasticity decreases.The results of low cycle fatigue tests show that,the larger blocky MC-type carbides formed in higher C content on the surface or sub-surface in the test sample lead to the lower fatigue lifetime.