选区激光熔化成形的304L不锈钢硬度和微观结构的研究  

Study on Hardness and Microstructure of 304L Stainless Steel by Selective Laser Melting

作　　者：李莹 李健健 侯娟 林俊[2] 戴志敏[2] 黄爱军 LI Ying;LI Jianjian;HOU Juan;LIN Jun;DAI Zhimin;HUANG Aijun(School of Materials Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Institute of Applied Physic,Chinese Academy of Science,Shanghai 201800,China;Monash Center for Additive Manufacturing(MCAM),Monash University,Notting Hill VIC 3168,Australia)

机构地区：[1]上海理工大学材料科学与工程学院,上海200093 [2]中国科学院上海应用物理研究所,上海201800 [3]莫纳什大学增材制造中心,墨尔本VIC3168

出　　处：《热加工工艺》2022年第10期24-29,共6页Hot Working Technology

基　　金：国家自然科学基金资助项目(11605272,52073176)。

摘　　要：选区激光熔化成形的奥氏体不锈钢与传统轧制材料相比,其硬度明显高于传统材料,这与其独特的微观结构密不可分。使用纳米压痕技术测量SLM打印态、SLM热处理态以及传统轧制3种304L奥氏体不锈钢的硬度变化,与材料的微观结构表征相结合,发展了一种使用硬度快速评价材料屈服强度的方法,并发现位错强化、细晶强化以及弥散强化是影响SLM 304L硬度的主要3种因素。结合理论计算分析了3种强化机制的作用。结果表明,高密度位错、析出相以及细小的晶粒尺寸共同造成了SLM打印态304L不锈钢具有最高的硬度,其中位错密度与晶粒尺寸是最主要的材料硬化因素。Selective laser melting(SLM) austenitic stainless steel has higher hardness than its traditional rolled counterparts, which was closely related to its unique microstructure. The nano-indentation measurement was applied to investigate the hardness evolution in three kinds of samples, including as-built and heat-treated SLM, and the traditional rolled 304L austenitic stainless steels. Combining with the microstructure characterization of the materials, a rapid method for evaluating the yield strength of the materials by hardness was developed. Dislocation strengthening, fine grain strengthening and dispersion strengthening are the three main factors affecting the hardness of SLM 304L. The results show that high density dislocations, precipitates and fine grain size jointly cause the highest hardness of 304L stainless steel as-built SLM. The dislocation density and grain size are the two main material strengthening factors.

关 键 词：选区激光熔化 304L不锈钢 纳米压痕 微观结构 

分 类 号：TG142[一般工业技术—材料科学与工程]