(西北工业大学 材料学院，西安 710072)
摘 要: 机械诱发局部剧烈塑性变形方法是钛合金表层纳米化的主要方法，主要包括表层机械研磨方法、超音速微粒轰击方法、高能喷丸方法和激光脉冲喷丸方法等。通过控制表层机械处理参数可在钛合金表层制备出一定厚度的纳米组织，并沿厚度方向由纳米晶逐渐过渡到基体的粗晶组织；表层纳米组织的形成明显提高了钛合金表层的强度、硬度和抗腐蚀性能等。钛合金的表层纳米化机理受α相和β相含量的影响较大，α相含量为主的钛合金中孪晶分割细化机制占主导地位；β相含量为主的钛合金中位错分割细化机制占主导地位。在总结钛合金表层纳米化近年来取得的进展基础上指出了该技术今后的研究发展方向。
关键字: 钛合金；表层纳米化；组织；力学性能；机理
（School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:Local severe plastic deformation via mechanical treatment is the main method for surface nanocrystallization of titanium alloys. The methods mainly include surface mechanical attrition, supersonic fine particles bombarding, high energy shot peening and laser shock peening. Nanostructured surface layer could be synthesized by controlling the processing parameters, and the microstructure gradually changes from nanocrystalline structure to the coarse grains in the base alloy along depth direction. The nonstructural surface layer increases the strength, hardness and corrosion resistance of titanium alloys evidently. The surface nanocrystallization mechanism of titanium alloys mainly depends on the content of α and β phases. The twin intersection mechanism dominate that the refinement in titanium alloys mainly consists of α phase, while the refinement in titanium alloys mainly consisting of β phase was induced by dislocation intersection instead. The investigation prospects of the surface nanocrystallization of titanium alloys via mechanical treatment were proposed on the basis of current status.
Key words: titanium alloy; surface nanocrystallization; microstructure; mechanical property; mechanism
