固溶处理对选区激光融化316L不锈钢晶间腐蚀性能行为的影响机制  

Effect of solution treatment on the intergranular corrosion behavior of 316L stainless steel fabricated by selective laser melting

作　　者：王保山 商强 满成 WANG Baoshan;SHANG Qiang;MAN Cheng(School of Materials Science and Engineering,Ocean University of China,Qingdao 266100,China)

机构地区：[1]中国海洋大学材料科学与工程学院,青岛266100

出　　处：《工程科学学报》2024年第6期1077-1088,共12页Chinese Journal of Engineering

基　　金：国家重点研发计划资助项目(2021YFE011400);国家自然科学基金资助项目(U2106216)。

摘　　要：选区激光融化316L不锈钢(SLM-316L不锈钢)常采用固溶处理进行组织优化、消减残余应力,以获得优异综合性能.奥氏体不锈钢的晶间腐蚀行为与其组织结构有较高的依赖性,因此固溶处理会提高SLM-316L不锈钢的晶间腐蚀性能.然而,固溶处理对SLM-316L不锈钢晶间腐蚀行为的影响规律和机制目前尚不清晰.基于此,本文首先对SLM-316L不锈钢进行1150℃固溶处理,随后采用SEM、EBSD、TEM等分析其组织结构特征和纳米氧化物颗粒形貌,最后采用双环电化学再活化和过硫酸铵电解试验研究其晶间腐蚀行为.主要结论如下:固溶处理后SLM-316L不锈钢发生再结晶,形成规则形状等轴晶粒及退火孪晶;纳米氧化物颗粒粗化,晶界处最大尺寸能够达到微米级,同时氧化物颗粒的类型也从菱矿石结构的MnSiO_(3)转变为尖晶石结构CrMn_(2)O_(4);固溶处理导致SLM-316L不锈钢晶间腐蚀性能下降,伴随着敏化时间的延长,晶间腐蚀类型从台阶状转变为沟状.Selective laser melting(SLM)is a powder-bed metal additive manufacturing technology that is extensively employed in the fields of marine engineering,biomedicine,and nuclear power due to its high processing precision and wide range of applicable materials.316L stainless steel is one of the metal materials that have been researched earlier and has a more mature process in the field of SLM.Although SLM technology processing of 316L stainless steel parts(later referred to as SLM-316L stainless steel)has been conducted for industrial applications,it is rarely utilized for high temperatures,strong corrosion,complex loads,and other demanding conditions.Nonequilibrium solidification in the laser melt pool is an inherent mechanism of the SLM-316L stainless steel forming process,which contributes to the production of a nonuniform organizational structure and a high level of residual stress,which influence the reliability of SLM-316L stainless steel in long-term service.Heat treatment after preparation of SLM-316L stainless steel is the most effective approach to optimizing the organizational structure and reducing residual stress.SLM of 316L stainless steel is often employed for solid solution treatment to optimize the organization and reduce residual stresses to yield remarkable overall performance.The intergranular corrosion behavior of austenitic stainless steel highly depends on its organizational structure;thus,solid solution treatment is bound to enhance the intergranular corrosion performance of SLM-316L stainless steel.However,the law and mechanism of the effect of solid solution treatment on the intergranular corrosion behavior of SLM-316L stainless steel is still vague.Based on the mentioned above,in this work,solid solution treatment of SLM-316L stainless steel is conducted at 1150℃,its organizational and structural characteristics and morphology of nanooxidized particles are examined by Scanning electron microscope(SEM),Electron backscattered diffraction(EBSD),and Transmission electron microscope(TEM),and its

关 键 词：晶间腐蚀 选区激光融化 316L不锈钢 热处理 组织结构 

分 类 号：TG172.9[金属学及工艺—金属表面处理]