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,对2A02铝合金进行了表面冲击试验。通过对激光冲击处理试样的HREM高分辨像观察,分析了激光冲击2A02铝合金材料微结构中的空位现象。结果表明,考察区域在激光冲击超高应变率作用下,在形成大量位错的同时,伴随形成相应的空位;空位片成为激光冲击超高应变率形变条件下铝合金基体中的特征微结构;空位和位错的重组作用加剧了点阵畸变,引起的第三类内应力和纳晶化提高了激光冲击表面的硬度和残余压应力。
Aluminum alloy 2A02 was strengthened by laser shocking using Nd： YAG laser with 1064 nm output wave length and 20 ns short pulse. The vacancy phenomenon of microstructure of the laser shocked aluminum alloy 2A02 was analyzed via images of HREM and IFFT. The experimental results indicate that a number of vacancies are produced at the shocked area of the samples together with the formation of dislocations due to the ultrahigh strain rate of laser shocking, the vacancy pieces become the characteristic mierostructure of the aluminum alloy matrix under the condition of plastic deformation via ultrahigh strain rate of laser shocking. The reconstruction between vacancy and dislocation, which intensifys the distortion of crystalline lattice and induces the third internal stress together with the nano crystallization, improves surface hardness and residual compressive stress of the laser shocked surface.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2012年第1期8-14,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(50735001
50905080)
