Y2O3对Ti-6Al-4V合金显微组织及力学性能的影响

Effect of YO on microstructure and mechanical properties of Ti-6Al-4V alloy

本文以Ti-6Al-4V+x Y2O3(x=0,0.2%,0.4%,0.6%,0.8%)粉末为原料,采用放电等离子烧结(SPS)工艺制备出Ti-6Al-4V+x Y2O3合金,利用光学显微镜和透射电镜探究Y2O3含量对Ti-6Al-4V合金显微组织和性能的影响。结果表明,添加Y2O3后会细化晶粒,当Y2O3含量超过0.2%之后,随着Y2O3含量的增加晶粒尺寸会逐渐增大;加入Y2O3后可以有效改善Ti-6Al-4V的力学性能,添加0.6%Y2O3时力学性能最好,屈服强度970 MPa、最大抗压强度1 852 MPa、压缩应变31.4%,较未添加稀土的Ti-6Al-4V合金分别提高7.8%、14.1%、19.4%,致密度提高到99.28%;Y2O3主要是通过提高Ti-6Al-4V制品的密度和在合金中的钉扎作用来提高力学性能。

The effect of Y2O3 content on the microstructure and mechanical properties of Ti-6 Al-4 V alloy produced by spark plasma sintering(SPS)using the Ti-6 Al-4 V+x Y2O3(x=0,0.2%,0.4%,0.6%,0.8%)powders as raw materials was investigated with optical microscopy and TEM. The results show that the grain size will be refined through adding Y2O3,when the content of Y2O3 exceeds 0.2%,the grain size will increase with the increase of Y2O3 content;and the mechanical properties of Ti-6 Al-4 V alloy can be effectively improved through adding Y2O3,when the content of Y2O3 equals to 0.2%,the Ti-6 Al-4 V alloy achieve its best mechanical properties,in which the yield strength,the maximum compressive strength and the compressive strain are 970 MPa,1 852 MPa and31.4% respectively,and improves by 7.8%,14.1% and 19.4% respectively compared with Ti-6 Al-4 V alloy without adding Y2O3,and its densification increases to 99.28%. The Y2O3 mainly improves the mechanical properties of Ti-6 Al-4 V alloy by increasing the density of Ti-6 Al-4 V alloy and the pinning effect in the alloy.