保护气氛对激光增材制造316L不锈钢组织和性能的影响  

Effect of Protective Atmosphere on Microstructure and Properties of 316L Stainless Steel Fabricated by Laser Additive Manufacturing

作　　者：顾玉芬[1] 陈计澎 李广[1] 石玗[1] GU Yufen;CHEN Jipeng;LI Guang;SHI Yu(State Key Laboratory of Advanced Processing and Reuse of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050

出　　处：《电焊机》2025年第2期18-24,共7页Electric Welding Machine

基　　金：中央引导地方科技发展资金项目(23ZYQA308);甘肃省科技重大专项(22ZD6GA008);甘肃省自然科学基金(21JR7RA233);甘肃省高等学校产业支撑计划(GCJ2022-38)。

摘　　要：研究不同保护气氛对增材制造不锈钢组织和力学性能的影响机制,为优化316L不锈钢的激光增材制造工艺提供理论依据。采用高速激光熔丝增材制造技术,分别在纯氩气和纯氮气保护气氛下制备316L不锈钢试样。通过扫描电子显微镜(SEM)、背散射衍射(EBSD)和X射线衍射(XRD)等手段对试样的微观组织进行表征,分析晶粒尺寸、晶粒取向及物相组成。利用拉伸试验机对试样进行力学性能测试,并断口形貌分析。研究结果表明,氩气和氮气保护气氛下,316L不锈钢的组织主要为奥氏体,少量铁素体分布在奥氏体晶界处。氮气保护气氛下的晶粒尺寸(平均59μm)较氩气保护气氛下的晶粒尺寸(平均66μm)更小,且氧化物夹杂颗粒的尺寸也有所减小。氮气作为强烈的奥氏体形成元素,促进了奥氏体的形核,起到了细化晶粒的作用。力学性能测试显示,氮气保护气氛下的试样抗拉强度(602.9 MPa)和屈服强度(220.5 MPa)均高于氩气保护气氛下的试样(分别为549.5 MPa和201.3MPa),且断后延伸率也有所提高。断口分析表明,两种气氛下的断裂类型均为韧性断裂,氮气保护气氛下的氧化物夹杂尺寸更小,从而提高了激光熔丝增材制造316L不锈钢的强度和塑性。This study investigates the influence of different protective atmospheres(argon and nitrogen)on the microstructure and mechanical properties of 316L stainless steel fabricated by laser wire additive manufacturing,aiming to optimize the laser additive manufacturing process for 316L stainless steel.High-speed laser wire additive manufacturing technology was employed to prepare 316L stainless steel specimens under pure argon and pure nitrogen atmospheres.The microstructure,including grain size,orientation,and phase composition,was characterized using scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),and X-ray diffraction(XRD).Mechanical properties were evaluated using tensile testing,and fracture morphology was analyzed.The results show that the microstructure of 316L stainless steel under both argon and nitrogen atmospheres is primarily austenitic,with a small amount of ferrite distributed at the austenite grain boundaries.The average grain size under nitrogen atmosphere(59μm)is smaller than that under argon atmosphere(66μm),and the size of oxide inclusions is also reduced.Nitrogen,as a strong austenite-forming element,promotes austenite nucleation and refines the grains.Tensile tests reveal that the specimens under nitrogen atmosphere exhibit higher tensile strength(602.9 MPa)and yield strength(220.5 MPa)compared to those under argon atmosphere(549.5 MPa and 201.3 MPa,respectively),along with improved elongation.Fracture analysis indicates that both atmospheres result in ductile fracture,with smaller oxide inclusions under nitrogen atmosphere,thereby enhancing the strength and plasticity of the laser wire additive manufactured 316L stainless steel.

关 键 词：激光增材制造 316L不锈钢 细化晶粒 保护气氛 

分 类 号：TG456.7[金属学及工艺—焊接]