金属材料在激光冲击表面改性中的微结构响应  

Microstructure Response of Metallic Materials in Surface Modification by Laser Shock Processing

作　　者：罗新民[1] 陈康敏[1,2] 张永康[3] 

机构地区：[1]江苏大学材料学院,江苏镇江212013 [2]江苏大学分析测试中心,江苏镇江212013 [3]江苏大学机械工程学院,江苏镇江212013

出　　处：《热处理》2013年第4期9-16,共8页Heat Treatment

基　　金：国家自然科学基金(50735001)资助项目

摘　　要：激光冲击表面改性技术是使金属材料表面受惯性和几何约束的被冲击区域局部强烈形变从而强化,具有小光斑逐点累积处理的特点。基于被冲击材料的约束状态,由于激光冲击的超高能量与超高应变率,材料将产生应变屏蔽效应。根据上述特点,通过SEM、TEM、HREM和IFFT综合研究了bcc、fcc和hcp晶型金属材料在激光冲击后的物理冶金学响应及其特点。分析了滑移、孪晶等微结构演变过程及马氏体相变、纳米化现象。讨论了激光冲击形变与常规形变的差异及激光冲击表面形变强化的位错机制。Laser shock processing is a surface modification technology which allows the shocked region of metallic material surface subjected to inertia and geometry confinements to produce locally drastic deformation and thus to be strengthened , and is characterized by continual and accumulative shocking with small laser spots .Based on the confinement conditions of material to be shocked , the material will offer strain screening effect owing to the ultra-high energy and the super-high strain rate of laser shocking .In the light of these features , the physic-metallurgical response and the characteristics of metallic materials with bcc , fcc and hcp crystalline lattices after laser shocking are synthetically investigated by means of SEM , TEM, HREM and IFFT.The evolution process of slip and twin , martensitic transformation and nano-crystallization are respectively analyzed .The difference between laser shock deformation and conventional deformation and the dislocation mechanism of strengthening materials by laser shock processing are also discussed .

关 键 词：激光冲击 金属材料 表面改性 微结构 材料表征 

分 类 号：TN249[电子电信—物理电子学] TG113[金属学及工艺—物理冶金]