Mn对生物医用Ti-Mo合金组织与力学性能的影响

Effect of manganese addition on microstructure and mechanical properties of Ti-Mo Biomedical alloys

采用非自耗真空电弧炉制备Ti-8Mo-xMn系列合金,以考察Mn的添加对生物医用Ti-Mo合金显微组织与力学性能的影响。结果表明:两元Ti-Mo合金主要由细小的针状α″马氏体相组成,加入1%Mn(质量分数)后,等轴晶的β相大部被保留;当Mn的加入量达到3%后,β相全部被保留到室温。拉伸力学测试发现:β相不稳定的Ti-8Mo-1Mn合金在拉伸过程中发生应力诱导的从β相到α″相的马氏体转变,呈现出"双屈服"现象。加入少量Mn(1%和3%)提高合金塑性,伸长率由35%最大提高到53%。Mn量增加到5%、7%后,合金强度得到大幅提高,抗拉强度最大由856 MPa提高到1201 MPa,同时伸长率为22%。所有含Mn合金的显微硬度都较高,最高为386HV,是两元Ti-Mo合金的(251HV)1.65倍。含ω相的Ti-8Mo-1Mn合金的弹性模量最高,达150 GPa。其它含Mn合金的弹性模量在76~87 GPa之间,与人骨骼的接近,有潜力成为生物医用材料。

A series of Ti-8Mo-xMn alloys were fabricated by nonconsumable electrode vacuum arc furnace, the effect of Mn addition on the structure and mechanical properties of the alloy was investigated. The results indicate that α″ phase-dominated binary Ti-Mo alloy exhibits a fine, acicular martensitic structure. When 1% Mn(mass fraction) is added, most of equiaxed β phase structure is retained. With Mn content increasing to 3%(mass fraction), entire β phase is retained. Mn alloy with instability β phase exhibits the two-stage yielding from stress-strain curves due to the stress-induced martensite transformation from β to α″ during tensile deformation. Addition of a small amount of Mn(1% and 3 %) improves the plasticity of alloys, and the elongation increases from 35% to 53%. With Mn content increasing to 5% and 7%(mass fraction), the strength dramatically improves and tensile strength increases from 854 MPa to 1201 MPa, companied with 22% elongation. All the alloys with Mn exhibits the high microhardness, the highest is 386 HV,which is 1.65 times than that of binary Ti-Mo alloy. The elastic modulus of Ti-8Mo-1Mn alloy with ω phase is the highest of all alloys 150 GPa. The elastic modulus of the other alloys with Mn are about 76~87 GPa, close to those of human skeletons. These alloys seem to have a great potential for use as an implant material.