论文部分内容阅读
报道了一种兼具低弹性模量和高强度的新型亚稳β型Ti-38Nb(%,质量分数)合金,并系统地研究了热-机械处理对合金微观组织及力学行为的影响。研究结果表明,Ti-38Nb合金经固溶处理后,由于合金中β稳定化元素含量不足,高温β相并没有完全保留至室温,合金中生成了大量的α″马氏体。此时,Ti-38Nb合金在较低的应力水平下(约207 MPa)便发生了马氏体变体的再取向和应力诱发马氏体相变,故无法满足生物医用材料对高强度的要求。经冷轧和673 K退火40 min后Ti-38Nb合金中引入了大量的位错和晶界,高密度的位错和晶界有效地抑制了ω相的析出和α″马氏体的产生。此时,β稳定化元素含量低的高温β相被稳定至室温,合金实现了低弹性模量(56 GPa)和高强度(拉伸强度1020 MPa)的良好匹配。因此,Ti-38Nb合金由于其低弹性模量和高强度特性有望在生物医用植入材料领域获得应用。
A new type of metastable β-Ti-38Nb (%, mass fraction) alloy with both low modulus of elasticity and high strength has been reported. The effects of thermo-mechanical treatment on the microstructure and mechanical properties of the alloy have also been systematically investigated. The results show that a large amount of α “martensite is formed in the alloy after the solution treatment of Ti-38Nb alloy due to the insufficient content of β stabilizing element in the alloy, and the high-temperature β phase is not completely retained to room temperature. -38Nb alloy can not meet the high strength requirements of biomedical materials due to the reorientation of martensite and stress-induced martensitic transformation at lower stress level (about 207 MPa) After annealed at 673 K for 40 min, a large number of dislocations and grain boundaries were introduced into the Ti-38Nb alloy. High-density dislocations and grain boundaries effectively suppressed the precipitation of ω phase and the formation of α ”martensite. At this time, the high-temperature beta phase with a low beta stabilizing element content is stabilized to room temperature and the alloy achieves a good match between low modulus of elasticity (56 GPa) and high strength (tensile strength 1020 MPa). Therefore, Ti-38Nb alloys are expected to find applications in biomedical implants because of their low elastic modulus and high-strength properties.