铸态Ti-20Zr-10Nb-xMo合金的微观组织和耐腐蚀性能

Microstructure and corrosion resistance of as-cast Ti-20Zr-10Nb-xMo alloys

采用X射线衍射仪(XRD)、光学显微镜(OM)、硬度测试、压缩试验和电化学工作站等研究了Mo含量对Ti-20Zr-10Nb-xMo(x=0,3,6,9,wt%)合金相结构、显微组织、力学性能以及电化学腐蚀性能的影响。结果表明,随着Mo含量的增加,Ti-20Zr-10Nb-xMo合金的相结构发生了α′+β→α″+β→β的变化,平均晶粒尺寸亦随着Mo含量的增加而逐渐降低;当Mo含量为9%时,合金的平均晶粒尺寸约为45μm。通过Mo的添加,合金的抗压强度和屈服强度呈现先降低后升高的趋势,而显微硬度则先增大后降低;当Mo含量为9%时,合金的抗压强度最大,为1610 MPa,压缩应变为50.9%。未添加Mo的试验合金的自腐蚀电流密度最小,为33.19 nA·cm^(-2),R_(p)值最大,为1531.52 kΩ·cm^(2),其耐腐蚀性最好。

Effect of Mo content on microstructure,phase composition,mechanical properties and corrosion resistance of as-cast Ti-20 Zr-10 Nb-xMo alloys(x=0,3,6,9,wt%)was studied by means of X-ray diffraction,optical microscope,microhardness test,compressive test and electrochemical workstation.The results show that with the increase of Mo content,the phase structure of Ti-20 Zr-10 Nb-xMo alloys obviously changes fromα′+β→α″+β→β,and the average grain size decreases gradually with the increase of Mo content.When the Mo content is 9%,the average grain size of the alloy is about 45μm.With the addition of Mo,the compressive strength and yield strength of the alloy first decrease and then increase,while the microhardness increases first and then decreases.When the Mo content is 9%,the compressive strength and compressive strain are 1610 MPa and 50.9%,respectively.The self-corrosion current density and R_(p) value of the tested alloy without Mo addition are the minimum of 33.19 nA·cm^(-2),the maximum of 1531.52 kΩ·cm^(2),respectively,and the corrosion resistance is the best.