钆含量对Ni-30Cr-5Fe-5Mo-xGd合金显微组织及力学性能的影响

Influence of Gadolinium Contents on Microstructure and Mechanical Properties of Ni-30Cr-5Fe-5Mo-xGd Alloys

采用真空中频感应炉熔炼制备了含1%、2%和3%Gd(质量分数)的Ni-30Cr-5Fe-5Mo-Gd合金。对合金进行了热锻、热轧及1050℃×10 min、水冷固溶处理,研究了钆含量对合金显微组织和力学性能的影响。结果表明:合金中的析出相为(Ni,Cr,Fe)5Gd金属间化合物,且随着钆含量的增加而增多;合金具有较好的室温力学性能,硬度高于230 HV0.2,抗拉强度大于700 MPa,断后伸长率为(50±5)%。随着钆含量的增加,合金的硬度和抗拉强度显著提高,断后伸长率下降,并且(Ni,Cr,Fe)5Gd相在奥氏体晶界的富集加剧,合金呈现出沿晶断裂和穿晶断裂共存的断裂特征。

Ni-30Cr-5Fe-5Mo-Gd alloys containing 1%,2%and 3%Gd by mass were fabricated by melting in a vacuum medium-frequency induction furnace.The alloys were hot forged,hot rolled,solution treated at 1050℃for 10 min and then water cooled.The effect of gadolinium contents on microstructure and mechanical properties of the alloys was investigated.The results showed that(Ni,Cr,Fe)5Gd intermetallic compounds precipitated in the alloys,and increased with the increase in gadolinium content,and that the alloys provided better mechanical properties such as hardness higher than 230 HV0.2,tensile strength higher than 700 MPa,and elongation of(50±5)%.As the gadolinium content increased,the alloys exhibited much higher hardness and tensile strength,and less elongation,as well as(Ni,Cr,Fe)5Gd phase became more concentrated at the austenite grain boundaries,with the alloy fracture being characterized by coexistence of intergranular and transgranular fracture.