2A02铝合金中强激光冲击诱导的位错组态分析  

Dislocation Configurations Induced by Laser Shock Processing of 2A02 Aluminum Alloy

作　　者：罗新民[1] 张静文[1] 马辉[1] 张永康[2] 陈康敏[1,3] 任旭东[2] 罗开玉[2] 

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

出　　处：《光学学报》2011年第7期159-165,共7页Acta Optica Sinica

基　　金：国家自然科学基金(50735001;50905080)资助课题

摘　　要：利用输出波长为1064 nm、脉冲宽度为20 ns的钕玻璃YAG激光器,对2A02铝合金进行了表面冲击强化试验。测定了激光冲击后材料的表面硬度和残余应力,用快速傅里叶逆变换(IFFT)方法分析了铝合金激光冲击诱导的晶内亚结构及其演变行为。结果表明,激光冲击强化可使2A02铝合金表面硬度提高50%以上,残余压应力达到120 MPa以上。微观组织的透射电镜(TEM)及IFFT分析结果表明,激光冲击区域晶内位错组态丰富,由刃位错和中心位错带等组成;位错墙可细化晶粒;位错偶极子聚集成为激光冲击非平衡形变条件下纳米晶内亚结构特征构元。激光冲击诱发的晶格内复杂的位错组态和晶格畸变是表面硬度和残余应力提高的主因。Aluminum alloy 2A02 is shocked by using the Nd：YAG laser with 1064 nm output wavelength and 20 ns pulse width.The surface hardness and residual stress of sample are measured,and the sub-structure of grain and its evolution behavior induced by laser shock are analyzed via the inverse fast Fourier transform（IFFT） method.The experimental results indicate that the surface hardness of the laser-shocked material increases by 50%,and the residual compressive stress of the laser-shocked test material reaches above 120 MPa.The transmission electron microscopy（TEM） and IFFT analysis of microstructure demonstrate that there are different types of dislocation configurations in the laser shocked area,mainly including edge dislocations and central dislocation bands;and the dislocation walls refine the original grain.The dislocation dipole close-array becomes the characteristic element of the nanocrystalline under the non-equilibrium deformation condition endowed by laser shock.Therefore,the complex dislocation configurations and the crystal lattice distortion induced by laser shocking are important to the improvement of surface hardness and residual stress.

关 键 词：激光技术 铝合金 激光冲击 微观组织 快速傅里叶逆变换 位错组态 

分 类 号：TN249[电子电信—物理电子学] TG146.21[一般工业技术—材料科学与工程]