(西北工業(yè)大學(xué) 材料學(xué)院，西安 710072)
摘 要: 機械誘發(fā)局部劇烈塑性變形方法是鈦合金表層納米化的主要方法，主要包括表層機械研磨方法、超音速微粒轟擊方法、高能噴丸方法和激光脈沖噴丸方法等。通過控制表層機械處理參數(shù)可在鈦合金表層制備出一定厚度的納米組織，并沿厚度方向由納米晶逐漸過渡到基體的粗晶組織；表層納米組織的形成明顯提高了鈦合金表層的強度、硬度和抗腐蝕性能等。鈦合金的表層納米化機理受α相和β相含量的影響較大，α相含量為主的鈦合金中孿晶分割細化機制占主導(dǎo)地位；β相含量為主的鈦合金中位錯分割細化機制占主導(dǎo)地位。在總結(jié)鈦合金表層納米化近年來取得的進展基礎(chǔ)上指出了該技術(shù)今后的研究發(fā)展方向。
關(guān)鍵字: 鈦合金；表層納米化；組織；力學(xué)性能；機理
（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
