奥氏体不锈钢表面激光冲击晶粒超细化的研究  

Investigation of Surface Ultra-refinement of Austenitic Stainless Steel Induced by Laser Shock Processing

作　　者：朱向群[1] 周明[1] 戴起勋[1] 任乃飞[1] 蔡兰[1] 

机构地区：[1]江苏大学,镇江212013

出　　处：《中国机械工程》2005年第17期1581-1585,共5页China Mechanical Engineering

基　　金：国家自然科学基金资助项目(50375068)

摘　　要：采用高能短脉冲激光冲击(LSP)技术获得具有亚微米晶体结构的奥氏体不锈钢表面层.利用扫描电镜(SEM)、透射电镜(TEM)和X射线衍射(XRD)等技术分析研究了表面层的微观结构特征.结果表明:单次激光冲击即可实现样品表层晶粒超细化,晶粒大小0.1～0.5μm,接近纳米级;晶格常数增加1.12%,处理区显微硬度显著提高,形变层深0.25mm.分析认为,在激光诱导、应变率达10 6s-1和高于靶材动态屈服强度的应力加载条件下,试样表面发生了热塑失稳和动态再结晶,致使晶粒超细化.Submicron-sized top layer was synthesized on an Austenitic stainless steel sample by adopting high energy and short pulse laser shock processing （LSP） technique. The substructure morphology and characteristics of the treated region was examined by SEM, TEM and XRD technique. It indicates that, after LSP, the grains in top layer could be refined to submicron size, ranging from 0.1 to 0.5μm and approaching nanoscale. The crystal lattics constant increases by up to 1.12% compared to the normal one. The hardness in the treated region increases significantly and the depth of plastic deformation is of approximate 0.25mm. Under the loading conditions of strain rate of 10^6/s order and the shock stress of above the dynamic yield strength of the target, the formation of submicron-sized grains and the surface hardness increasing, might be attributed to occurrence of thermoplastic destabilization and dynamic recrystallization in the impacted region of sample surface layer imposed by LSP.

关 键 词：激光冲击 奥氏体不锈钢 表层 晶粒超细化 

分 类 号：TG142.71[一般工业技术—材料科学与工程]