(1. 西安建筑科技大学 冶金工程学院，西安 710055；
2. 西安圣泰金属材料有限公司，西安 710018)
摘 要: 利用X射线衍射仪(XRD)、光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)和拉伸测试等手段，研究形变热处理对新型β(Ti-25Nb-25Zr)钛合金组织演变和力学性能的影响。结果表明：由于合金具有较高的β稳定性，冷轧过程没有应力诱发α″相的形成，合金的变形机制以位错滑移为主。随着冷轧变形量的增加，加工硬化速率和弹性模量逐渐降低。经过相同的时效处理(300 ℃、2 h), 固溶态和冷轧态的合金相组成分别为β+等温ω和β+α相。冷轧产生的位错缺陷和晶界有效抑制ω相，促进了α相的析出。冷轧时效相比固溶时效能更好地得到较高的强度和理想的弹性模量，满足医用材料的性能要求。
关键字: Ti-25Nb-25Zr钛合金；冷轧变形；时效处理；组织演变；力学性能
（1. School of Metallurgical Engineering, Xi’an University of Architecture & Technology, Xi’an 710055, China;
2. Xi’an Seatell Metal Materials Co., Ltd., Xi’an 710018, China）
Abstract:The effects of thermo-mechanical treatment on microstructure and mechanical properties of Ti-25Nb-25Zr alloy were investigated by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tension tests. The results show that the alloy exhibits excellent phase stability that no stress-induced α″ phase transition occurs during cold rolling and the plastic deformation mechanisms are related to dislocation slipping. With the increase of the cold deformation, the hardness and elastic modulus decrease gradually. It’s found that the phase composition of aging products for the solution treated and the cold-rolled alloys are β+ω and β+α phases at 300 ℃ for 2 h. The cold deformation produces much more dislocation defects and grain boundaries inhibits the nucleation of the ω phase, while α phase tends to nucleate at the dislocations and grain boundaries to promote the precipitation of α phase. Compared with solution and aging, the aging treatment after cold deformation has high strength and ideal elastic modulus can satisfy the requirements for dental implant.
Key words: Ti-25Nb-25Zr alloy; cold-rolling deformation; aging treatment; microstructure evolution; mechanical properties
