YbB_(6)对Ti-6Al-4V钛合金组织和性能的影响

Effect of YbB_(6) on Microstructure and Mechanical Properties of Ti-6Al-4V Titanium Alloy

采用放电等离子烧结(SPS)制备了含YbB的Ti-6Al-4V钛合金,并研究了YbB对Ti-6Al-4V钛合金显微组织和力学性能的影响。结果表明,随着YbB含量的增加,复合材料的显微组织发生转变,晶粒明显细化,原位反应生成的Ti B晶须和Yb2O3颗粒有利于复合材料力学性能的提高。此外,当添加0.6%(质量分数)YbB后,烧结样品的相对密度、显微硬度、屈服强度、极限拉伸强度和延伸率分别为99.43%、4030 MPa、903 MPa、1148 MPa和3.3%。与Ti-6Al-4V试样相比,其数值分别提高了0.37%、13.8%、38.07%和17.14%。强化机制主要是组织转变、晶粒细化和弥散强化。随着YbB含量的增加,断裂方式主要为韧性断裂和脆性断裂。

The Ti-6Al-4V titanium alloy with YbBaddition was fabricated by spark plasma sintering(SPS), and the effects of YbBaddition on microstructure and mechanical properties of Ti-6Al-4V titanium alloy were investigated. The results show that with increasing the YbBcontent, the microstructure of the composites is clearly changed, and the grains are obviously refined. The in-situ formation of TiB whiskers and YbOparticles is beneficial to the improvement of mechanical properties of the composites.Furthermore, with the addition of 0.6wt% YbB, the relative density, microhardness, yield strength, ultimate tensile strength, and elongation of the sintered alloys are 99.43%, 4030 MPa, 903 MPa, 1148 MPa, and 3.3%, respectively. Compared to those of Ti-6Al-4V alloy, the aforementioned properties of the sintered alloys with 0.6wt% YbBare increased by 0.37%, 13.8%, 38.07%, and 17.14%,respectively. The strengthening mechanism is mainly attributed to the microstructure transformation, grain refinement, and dispersion strengthening. With increasing the YbBcontent, the fracture mode is the combination of ductile fracture and brittle fracture.