激光增材制造24CrNiMo合金钢显微组织特征  

Microstructure features of 24CrNiMo alloy steel fabricated by laser additive manufacturing

作　　者：徐昀华 张春华[1] 张松[1] 乔瑞庆[1] 张静波[2] XU Yun-hua;ZHANG Chun-hua;ZHANG Song;QIAO Rui-qing;ZHANG Jing-bo(School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China;Shenyang Dalu Laser Technology Corporation,Shenyang 110136,China)

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870 [2]沈阳大陆激光技术有限公司,沈阳110136

出　　处：《材料工程》2020年第11期147-154,共8页Journal of Materials Engineering

基　　金：国家重点研发计划(2016YFB1100204);辽宁省重点研发计划(2018106004);沈阳市科技计划(19-109-1-03)。

摘　　要：采用激光选区熔化技术和激光熔化沉积技术制备24CrNiMo合金钢单道和块体样品,研究两种激光辐照条件下24CrNiMo低合金钢的相组成、微观组织、织构特征和显微硬度。结果表明:两种方法制备的24CrNiMo合金试样的相组成均为α-Fe相以及少量的Fe 3C;SLM成形单道沉积样品的晶粒取向随机、无序,无明显的择优取向,而LMD成形单道沉积样品的择优取向为(110)〈101〉面织构;SLM成形块体样品的晶粒在平行于沉积方向上存在较弱的〈111〉织构,LMD成形块体样品的晶粒存在外延生长取向为〈111〉的强织构;SLM成形试样的显微组织主要为下贝氏体,而LMD成形试样的显微组织以板条贝氏体为主;具有细小晶粒和下贝氏体组织的SLM成形试样的平均显微硬度高于LMD试样。Herein,the single-track and block samples of 24CrNiMo alloy steel were prepared by selective laser melting(SLM)technology and laser melting deposition(LMD)technology.The phase composition,microstructure,texture types and micro-hardness of 24CrNiMo low alloy steel under two laser irradiation conditions were studied.The results show that the main phase compositions of 24CrNiMo alloy samples prepared by two methods areα-Fe phase and a small amount of Fe 3C.Furthermore,the grain orientation of SLM single-track deposited sample is random and disordered,and there is no obvious preferred orientation.However,the preferred orientation of LMD single-track deposited sample is the(110)〈101〉plane texture.The grain of SLM block sample has weak〈111〉texture parallel to the deposition direction,LMD block sample has strong texture with the〈111〉epitaxial growth orientation.Additionally,the main microstructure of as-built SLM sample is lower bainite,and the microstructure of as-deposited LMD sample mainly consists of lathbainite.The average micro-hardness SLM sample with fine grain and lower bainite microstructure is higher than that of LMD sample.

关 键 词：激光选区熔化 激光熔化沉积 24CrNiMo合金钢 显微组织 织构 

分 类 号：TG142.45[一般工业技术—材料科学与工程]