针对镁合金表面连续Mg-Al金属间化合物扩渗层形成温度过高及耐磨性不足的关键问题，采用冷喷超音速微粒碰撞诱导镁合金表面纳米化，通过机械合金化制备陶瓷增强Al基纳米复合粉末，利用冷喷材料原位移植特性，实现镁合金纳米化表面Al基纳米复合涂层的可控沉积，基于“双纳米化”高活性实现镁合金表面连续Mg-Al金属间化合物基扩渗层的低温形成，同时，通过Mg-Al扩渗层与镁合金及Mg-Al扩渗层内陶瓷颗粒与基体相间“双界面”协同强化，提高扩渗层耐磨损性能。研究冷喷微粒碰撞镁合金表面变形层的结构特征，阐明纳米化过程和机制，研究Al基纳米复合粒子碰撞瞬间的塑性变形机理及内部陶瓷颗粒流动特征，揭示其沉积行为及影响涂层可控沉积的因素，研究纳米晶尺寸及热扩渗工艺对Mg-Al金属间化合物基扩渗层结构及性能的影响，阐明其形成的宏观趋势和微观机制，为镁合金表面抗腐耐磨连续Mg-Al金属间化合物基扩渗层的制备提供理论基础。

Aim at the two key problems of the high diffusion temperature and low wear resistance of Mg-Al intermetallics diffusion layer on magnesium alloy surface, a method is proposed to prepare the continuous Mg-Al intermetallic matrix diffusion layer at low diffusion temperature. Firstly, surface nano-crystallization of magnesium alloy is induced by supersonic fine particles bombardment (SFPB) based on the modified cold spraying technology; Secondly, ceramic reinforced aluminum matrix nanocomposite powder is prepared by mechanical alloying process. Thirdly, a aluminum matrix nanocomposite coating is deposited on the nano-crystallization surface of magnesium alloys through cold spraying process due to its in-situ material transplantation characteristics. Finally, the dense Mg-Al intermetallic matrix diffusion layer is produced on the magnesium alloys surface through diffusion treatment at low temperature based on the high activity of “dual nanostructures”. At the same time, the wear resistance of the Mg-Al diffusion layer is significantly improved based on the synergistic strengthened effect of the interface bodings between magnesium alloy and diffusion layer and between ceramic reinforced particles and Mg-Al substrate. In this project, the microstructure features of surface deformation layer on magnesium alloys resulted from the supersonic particles collide is investigated in order to clarify its surface nano-crystallization process and mechanism. The plastic deformation behavior of aluminum matrix nanocomposite particle and the flow characteristics of ceramic hard phase in the composite powder at the moment of collision between single aluminum-ceramic composite particle and substrate are studied. The deposit behavior and microstructure formation mechanism of cold-sprayed aluminum matrix nanocomposite coating are examined. The influence of the nanostructure characteristics of magnesium substrate and cold-sprayed aluminum matrix naocomposite coatings and diffusion parameters on the microstructure evolution and properties of Mg-Al intermetallic matrix diffusion layer are studied. The macro-trends and micro-mechanism of microstructure formation of the Mg-Al intermetallic matrix diffusion layer during diffusion process are investigated. A theoretical basis for the preparation of high corrosion and wear resistant Mg-Al intermetallic matrix composite coating diffusion layer on magnesium alloy surface is provided.