面向航空发动机长寿命可靠运行的需求，针对钛合金叶片疲劳寿命短和强化变形大的难题，本项目拟以α+β双相钛合金叶片为研究对象，开展激光冲击钛合金微结构响应机制和动态塑性变形行为研究，主要包括：⑴研究双相钛合金双相及界面的位错组态分布，揭示激光冲击双相钛合金的微结构响应机制；⑵描述大面积多点搭接冲击的微观塑性变形过程，建立激光冲击钛合金塑性形变深度的解析表达式，获得微观塑性变形导致的累积宏观变形规律；⑶描述力学效应下动态晶粒演变过程，获得深度方向的微观结构演化规律，揭示超激光冲击双相钛合金的晶粒细化机制；⑷探索激光冲击双相钛合金的形变能量-微观结构效应，获得激光冲击强化双相钛合金的工艺准则，从而实现激光冲击双相钛合金强化效果及表面塑性变形控制。相关内容涉及众多全新科学问题，研究成果可以丰富和发展双相合金表面改性理论和技术，为激光冲击强化钛合金叶片的大规模工业应用提供理论依据。

To solve the large deformation generated by laser shock peening (LSP) and short fatigue life of the dual-phase titanium alloy, the aim of this proposal is to address the micro-structural response mechanism and dynamic plastic deformation behavior of dual-phase titanium alloy under the mechanical effect of massive LSP impacts. This research can be used to ensure the longlife and reliable service of some key components used in aero-engine. The following issues will be involved. The first is to investigate the dislocation configuration distribution of α-phase, β-phase and α/β interface, and reveal the micro-structural response mechanism of dual-phase titanium alloy subjected to LSP. The second is to describe the plastic deformation process of dual-phase titanium alloy subjected to LSP, develop the analytical expression of plastic deformation depth of dual-phase titanium alloy subjected to LSP, and obtain the cumulative macroscopic deformation rule of dual-phase titanium alloy generated by microscopic plastic defoemation. The third is to describe the evolution process of the dynamic grain under the mechanical effect, gain the micro-structural evolution in the depth direction, and reveal the grain refinement mechanism of dual-phase titanium alloy subjected to LSP. The last is to explore the effect between deformation energy and microstructure, and obtain the technic principle of dual-phase titanium alloy subjected to LSP. As a result, the surface mechanical properties and plastic deformation of dual-phase titanium alloy can be predicted and controlled during massive and overlapping LSP impacts. The above researches involve many new scientific issues, and these research achievements can not only enrich and develop the surface modification technology and basic theory of dual-phase alloys, but also provide theoretical guidance for their large-scale industrial applications of fan blade strengthened by massive LSP impacts.