中文摘要：

用工业纯Al（α-Al）和Al-Cu-Mg系航空铝合金2A02进行了激光冲击表面改性实验，借助TEM从微结构响应的位错机制研究了不同靶材对强化效果的影响．结果表明，2种材料的强化效果有显著差异．α-Al激光冲击强化机制可归因于位错增殖．随激光冲击次数增加，新生位错发生塞积，并与林位错发生交互作用，位错线逐步演变为曲折波形、位错网络和位错缠结，但其硬度曲线冈Bauschinger效应（BE）和应力波阻尼而呈线性快速衰退．锅合金2A02的激光冲击强化机制呵归结为，由于高的基体强度和弥敞析出相的钉扎作用而增强位错的弹性能与激光冲击超高能缓的匹配，以及冲击诱发的位错增殖在析出相之间形成的复杂位错网络．随激光冲击次数增加，基体与析出相之间以增强的半共格关系协调形变；位错增殖和空位运动构成几何必须位错界面（GNBs），由其构成的、旺品界将基体金属细化至纳米级．复杂位错组态所致内应力和纳米化作用共同构成铝合金材料激光冲击表面改性的强化饥理．

英文摘要：

Surface modification experiment of the commercial purity aluminum （α-A1） and A1 Cu Mg alloyed aviation aluminum alloy 2A02 by laser shock processing （LSP） was implemented. The surface strengthening effect of both the target materials was investigated from dislocation Inechanisms of microstruetural response by means of TEM method. The results show that the strengthening effect of the two kinds of materials by laser shock processed is significantly different. The strengthening mechanism of α-A1 by laser shock can be attributed to tile multiplication of a large number of dis- locations. With the increase of the impact number of laser shock and the degree of deformation, the new generated dislocations will pile up and interact with the forest dislocations, and the dislocation lines will gradually evolve into waved like, or wind into dislocation tangles and dislocation networks.But the hardness curve of the laser shocked （α-A1） will fast and linearly decline due to Bauschinger effect （BE） and stress wave damping. The laser shock strengthening mechanisms of the aging-hardened aluminum alloy 2A02 can be summarized to the enhancement of the matching between the elastic energy of dislocations with the ultrahigh energy of laser shock processing due to the higher matrix strength and the dislocation pinning effect of large number of dispersed precipitates, as well as the complex dislocation networks in between the precipitates constructed by the dislocations induced by laser shock. The matrix strengthened by laser shock processing and the precipitates keep the extra semi coherent relationship to coordinate the total deformation, with the number of laser shock increase, dislocation multiplication and the vacancy motion constitutes geometrically necessary boundaries （GNBs）, which consists of the sub-grain boundaries to refine the matrix into the nanometer-grains. The strengthening mechanism of surface modification of aluminum alloy by laser shock processing is formed of the internal stress state caused b