Wang Chang-Jun, Liu Chang, Zhang Meng-Xing, Jiang Lu, Liu Yu, Liu Zhen-Bao, Liang Jian-Xiong
Central Iron & Steel Research Institute Company Limited, Beijing 100081, China.
Institute for Frontier Materials, Deakin University, Geelong, VIC 3216, Australia.
Materials (Basel). 2022 Aug 8;15(15):5441. doi: 10.3390/ma15155441.
In the present work, PH13-8Mo stainless steel parts without yttrium and with yttrium (Y) were manufactured by selective laser melting (SLM). The microstructure, phase composition and grain orientation of the stainless steels parts with Y and without Y were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), electron-backscatter diffraction (EBSD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The characterization results revealed that the addition of Y clearly refined the grain size of the PH13-8Mo steel formed part, resulting in more equiaxed massive grains and in a less anisotropic microstructure. PH13-8Mo stainless steel formed parts were mainly composed of martensite and retained austenite. The addition of Y could significantly increase the content of retained austenite and also generate nano-sized precipitates containing Y. The mechanical test results showed that both strength and toughness of the shaped parts containing Y were improved synergistically. The yield strength reached 1443 MPa, the elongation was 12.2%, and the room temperature impact energy reached 124.25 J/cm. The strengthening and toughening by Y of the formed parts were mainly attributed to grain refinement, higher volume fraction of the retained austenite and the formation of nano-sized precipitates containing Y.
在本研究中，通过选择性激光熔化（SLM）制造了不含钇和含钇（Y）的PH13 - 8Mo不锈钢零件。采用扫描电子显微镜（SEM）、X射线衍射（XRD）、电子背散射衍射（EBSD）、透射电子显微镜（TEM）和高分辨率透射电子显微镜（HRTEM）对含Y和不含Y的不锈钢零件的微观结构、相组成和晶粒取向进行了表征。表征结果表明，添加Y明显细化了PH13 - 8Mo钢成型零件的晶粒尺寸，产生了更多等轴块状晶粒，且微观结构的各向异性降低。PH13 - 8Mo不锈钢成型零件主要由马氏体和残余奥氏体组成。添加Y可显著增加残余奥氏体的含量，并生成含Y的纳米级析出物。力学测试结果表明，含Y的成型零件的强度和韧性均得到协同提高。屈服强度达到1443 MPa，伸长率为12.2%，室温冲击能量达到124.25 J/cm。Y对成型零件的强化和增韧作用主要归因于晶粒细化、较高体积分数的残余奥氏体以及含Y的纳米级析出物的形成。
