激光粉末床熔融(L⁃PBF)增材制造316L不锈钢制件微观表征和力学性能研究  

Microstructural Characterization and Mechanical Properties of 316L Stainless Steel Parts Prepared by Laser Powder Bed Fusion(L⁃PBF)Additive Manufacturing

作　　者：张澳 吴王平[1] 江鹏[1] 王知鸷[1] 潘海军 张屹 Zhang Ao;Wu Wangping;Jiang Peng;Wang Zhizhi;Pan Haijun;Zhang Yi(Metal 3D Printing Laboratory,School of Mechanical Engineering and Rail Transit,Changzhou University,Changzhou 213164,Jiangsu,China)

机构地区：[1]常州大学机械与轨道交通学院金属3D打印实验室,江苏常州213164

出　　处：《中国激光》2024年第12期148-161,共14页Chinese Journal of Lasers

基　　金：常州市科技项目(CJ20190041)。

摘　　要：以激光粉末床熔融(L-PBF)增材制造的316L不锈钢作为研究对象,重点研究了0°和60°两个不同成型方向对打印件显微组织和力学性能的影响,并利用原位电子背散射衍射(EBSD)技术研究了L-PBF 316L不锈钢在拉伸变形过程中组织和晶粒取向的演变过程。研究结果表明:L-PBF增材制造316L不锈钢的显微组织存在孔洞缺陷,在60°成型方向上还存在着鱼鳞状微熔池。成型方向为60°时制件的抗拉强度更高,为(645.61±15.50)MPa,0°成型方向上制件的伸长率更好,为(13.75±0.1)%。在原位拉伸过程中,随着变形量的增加,在0°成型方向上制件表现出更为显著的变化。小角度晶界的占比(体积分数)由38.1%增加到71.6%,α-Fe-BCC占比(体积分数)由0.17%增加到2.21%,平均晶粒尺寸由4.3μm减小到1.4μm,且晶粒内部在拉伸过程中出现了滑移带。在拉伸过程中,当成型方向为0°时,制件晶粒取向由初始的<101>∥Z1逐渐转变为<001>∥X1和<111>∥X1,而当成型方向为60°时,制件初始的<111>∥Z1晶粒取向逐渐转变为<111>∥X1。Objective Laser powder bed fusion(L-PBF)is a representative technology in metal/alloy additive manufacturing.It utilizes a laser as the heat source with a small beam size,enabling the production of fine and intricate parts.During L-PBF additive manufacturing of complex structure parts,the forming direction is variable which increases the complexity of heat transfer and solidification.As a result,the thermal efficiency differs among different forming directions,which can impact the performance of the printed parts.However,the current research on the influence of forming direction on the microstructure and properties of L-PBF 316L stainless steel is not sufficiently systematic.Therefore,it is further necessary to deeply investigate the influence of formation direction.We investigated the correlation between the forming direction and the microstructure and properties of L-PBF 316L stainless steel and explored the variations in mechanical properties to provide valuable insights for the development and applications of L-PBF 316L stainless steel.Methods First,the 316L stainless steel parts were fabricated using L-PBF from two different forming directions of 0°and 60°.The microstructure and mechanical properties of the parts were investigated through metallographic and tensile tests.The phases of the 316L stainless steel powder and as-printed samples were determined using X-ray diffraction(XRD).The grain orientation distributions,grain sizes,and grain boundary angles of these samples at different deformation strains were characterized using electron backscattered diffraction(EBSD)and scanning electron microscope(SEM).Results and Discussions The results show that some porosity defects occur in the L-PBF 316L stainless steel(Fig.5).During the printing process,the rapid cooling rate leads to the retention of theα-Fe ferrite phase(Fig.6).Tensile testing shows that the samples printed from the forming direction of 60°exhibit higher tensile strength than those from the forming direction of 0°,while the samples printed fr

关 键 词：激光技术 激光粉末床熔融增材制造 原位电子背散射衍射 成型方向 

分 类 号：TN249[电子电信—物理电子学]