热处理对激光选区熔化18Ni300马氏体时效钢微观组织和力学性能的影响  

Effect of Heat Treatment on Microstructure and Mechanical Properties of Selective Laser Melted 18Ni300 Maraging Steel

作　　者：向超 张涛[1] 吴文伟 邹志航 孙勇飞 刘金鹏 徐小蕾 韩恩厚 Xiang Chao;Zhang Tao;Wu Wenwei;Zou Zhihang;Sun Yongfei;Liu Jinpeng;Xu Xiaolei;Han Enhou(Institute of Corrosion Science and Technology,Guangzhou 510530,Guangdong,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,Liaoning,China;School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,Guangdong,China;School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641,Guangdong,China)

机构地区：[1]广东腐蚀科学与技术创新研究院,广东广州510530 [2]中国科学院金属研究所,辽宁沈阳110016 [3]广州大学物理与材料科学学院,广东广州510006 [4]华南理工大学材料科学与工程学院,广东广州510641

出　　处：《中国激光》2024年第16期168-177,共10页Chinese Journal of Lasers

基　　金：广东腐蚀科学与技术创新研究院青年创新基金(E1551601)。

摘　　要：使用电子万能材料试验机对不同热处理后的18Ni300马氏体时效钢进行拉伸试验,并通过X射线衍射(XRD)分析了不同热处理后马氏体及奥氏体的含量,研究了18Ni300钢在不同热处理过程中的组织演变、力学性能以及二者的关系,对比了其在不同热处理后的综合力学性能,从而筛选出了最佳热处理工艺。结果表明,热处理后试样的熔道逐渐消失,马氏体组织特征更加明显,硬度从34.1 HRC上升到52~54 HRC,抗拉强度从1174 MPa上升到2000 MPa以上。490℃直接时效6 h后实现了较好的强韧组合,这与组织内生成的强韧化相(逆转奥氏体)的含量密切相关。XRD测试结果表明,490℃直接时效后,试样内部具有最高的逆转奥氏体含量(体积分数约为6.9%),这些细小的逆转奥氏体分布在马氏体边界和内部,在一定程度上改善了18Ni300钢的韧性。Objective In recent years,significant progress has been made in preparing conformal cooling dies for die casting using additive manufacturing technology.Among these advancements,18Ni300 maraging steel has been widely applied because of its excellent forming characteristics.Currently,most research on selective laser melting(SLM)manufacturing of 18Ni300 maraging steel has primarily focused on the changes in microstructure after a heat treatment and the influence of precipitate phases on the strength,with limited emphasis on the impact of toughness.However,toughness plays a crucial role in determining the service life and safety of the molds.Although previous studies have explored reverse-austenite,systematic research on the toughness of 18Ni300 is currently lacking.Therefore,this study aims to systematically investigate the impact of the aging and solution temperatures on the microstructure and mechanical properties of 18Ni300 maraging steel.Additionally,it will specifically analyze the influence of reverse-austenite on the strength and plasticity of 18Ni300 maraging steel prepared using SLM technology.This study clarifies the relationship between the process,structure,and performance of 18Ni300 maraging steel,and proposes an optimal heat-treatment system.These findings offer valuable guidance for the practical application of this steel in various industries.Methods In this study,18Ni300 powder was used as the raw material.Experimental samples were obtained through selective laser melting(SLM)using an appropriate method.Following the formation,the samples were subjected to various heat treatments.The bulk samples were ground and polished with sandpaper,followed by etching with a 4%nitric-acid solution in alcohol.The microstructure was examined using optical microscopy(OM)and scanning electron microscopy(SEM).The mechanically polished samples were additionally polished with SiO2 and the crystal structure of the material was analyzed using electron backscatter diffraction(EBSD).X-ray diffraction(XRD)was utilized to a

关 键 词：激光技术 激光选区熔化 18Ni300马氏体时效钢 逆转奥氏体 热处理 拉伸性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]