基于亚稳ω过渡相辅助形核+晶粒细化制备高强医用β钛合金组织演化及力性调控机理

The secondary α phase in the biomedical beta type titanium alloy can be refined and uniformly distributed during aging treatment by meta-stable ω transition phase assisted nucleation method, and improve the strength, hardness and fatigue resistance performance of the alloy. However, a few researches on this respect were carried out just in recent years. The relevant technologies and theoretical research achievements are rarely reported. There is lack of the research on the effect of microstructure evolution and mechanical properties regulation mechanism of ω phase precipitation behavior on aging α phase nucleation and precipitation. Furthermore, the room temperature ductility reduces by this method. Research shows that the ductility can be improved by refining β grain sizes after aging treatment. Thus, in order to improve the strength-ductility matching degree, this project presents combine the ω phase assisted nucleation method and β grains refinement to prepare high strength biomedical β type alloy (Ti-10Mo-6Zr-4Sn-3Nb, wt%). To optimize and improve the method and theory system of biomedical β type titanium alloy ω phase assisted nucleation, obtain the precipitation conditions and evolution rules, and then verify the precipitation controlling and transformation mechanism of ω phase. Revealing the microstructure evolution laws of ω phase assisted secondary α phase nucleation, and clarifying the strengthening mechanism of the alloy.

利用亚稳ω过渡相辅助形核方法，能够使医用β钛合金在时效过程中获得的次生α相变得更加均匀细小，强度、硬度和抗疲劳性能得到显著提高。但是，关于该方面的研究仅从近几年才开始进行，且相关工艺技术和理论研究成果仍鲜有报道，特别是缺乏有关ω相析出行为对时效α相形核与析出组织演化的影响规律及力学性能调控机理方面的研究。此外，利用ω相辅助形核方法，会导致合金室温塑性下降。研究表明，经时效后的医用β钛合金塑性能够通过细化β晶粒尺寸而改善。所以，针对利用该方法引起室温塑性降低的问题，以优化和完善医用β钛合金ω相辅助形核方法和理论体系为目标。项目提出将ω相辅助形核与β晶粒细化方法相结合，制备高强医用β钛合金（Ti-10Mo-6Zr-4Sn-3Nb，wt%），使得其强-塑匹配度提高，掌握ω相的析出条件及演变规律，探明ω相的析出控制与转变机制，揭示ω相辅助次生α相形核的微观组织演变规律，阐明材料的强化机制。

利用亚稳ω过渡相辅助形核方法，能够使医用β钛合金在时效过程中获得的次生α相变得更加均匀细小，强度、硬度和抗疲劳性能得到显著提高。但是，关于该方面的研究仅从近几年才开始进行，且相关工艺技术和理论研究成果仍鲜有报道，特别是缺乏有关ω相析出行为对时效α相形核与析出组织演化的影响规律及力学性能调控机理方面的研究。此外，利用ω相辅助形核方法，会导致合金室温塑性下降。研究表明，经时效后的医用β钛合金塑性能够通过细化β晶粒尺寸而改善。所以，针对利用该方法引起室温塑性降低的问题，以优化和完善医用β钛合金ω相辅助形核方法和理论体系为目标。项目提出了将ω相辅助形核与β晶粒细化方法相结合，制备了高强医用β钛合金（Ti-10Mo-6Zr-4Sn-3Nb，wt%），使得其强-塑匹配度提高，掌握了ω相的析出条件及演变规律，探明了ω相的析出控制与转变机制，揭示了ω相辅助次生α相形核的微观组织演变规律，阐明了材料的强化机制。团队发表论文7篇（SCI），参加学术会议7次并做分会邀请报告7次，培养硕士研究生2名。