激光/等离子定向能量沉积316L不锈钢成型尺寸及力学性能的对比  

Comparative Forming Size and Mechanical Properties of 316L Stainless Steel Fabricated Using Laser/Plasma Arc Directed Energy Deposition

作　　者：秦文韬 杨永强[1] 翁昌威 韩昌骏 Qin Wentao;Yang Yongqiang;Weng Changwei;Han Changjun(School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou Guangdong510640 China.)

机构地区：[1]华南理工大学机械与汽车工程学院,广东广州510640

出　　处：《中国激光》2021年第22期54-63,共10页Chinese Journal of Lasers

基　　金：广东省重点研发计划(2018B090905001);国家自然科学基金(U2001218,51875215,81772428);广东省特支计划(2019TQ05Z110);广东省区域联合基金重点项目(2020B1515120013)。

摘　　要：作为当前最热门的增材制造技术之一,定向能量沉积可以实现大尺寸零件的高效成型。激光和电弧是定向能量沉积系统中最常用的热源,但它们在能量输入、能量分布以及与材料的作用机制等方面都存在差异。为此,本文对比了激光和等离子定向能量沉积316L不锈钢单道和薄壁件在尺寸、显微组织、力学性能方面的差异,以揭示两种工艺成型零件的差异。结果表明,在所选的工艺窗口内,激光在冷基板上沉积首层的结合效果要好于等离子。等离子定向能量沉积和激光定向能量沉积的工艺参数对单道尺寸的影响程度不同:在等离子定向能量沉积过程中,电流对层宽的影响最大,然后依次为送粉量和扫描速度,送粉量对层高的影响最大,之后依次是电流和扫描速度;在激光定向能量沉积过程中,扫描速度对层宽的影响最大,然后依次是送粉量和激光功率,送粉量对层高的影响最大,之后依次为扫描速度和激光功率。拉伸试验和显微硬度的测试结果表明:等离子定向能量沉积样件与激光定向能量沉积样件的力学性能相近,激光成型试样的抗拉强度可达593 MPa,等离子成型试样的抗拉强度可达570 MPa;但两者的显微组织存在较大差别,等离子成型试样中以定向生长的细长柱状晶为主,而激光成型试样中的柱状晶较短,不同区域的柱状晶生长方向各异。Objective Directed energy deposition(DED)is a popular additive manufacturing technology that uses a high-energy beam to melt metal powders and deposit them onto a substrate.It has the advantage of printing large-scale metal parts efficiently.Common high-energy sources for DED systems include laser,plasma arc,and electron beam.Laser DED(L-DED)is considered to print parts with better mechanical performance but low printing efficiency compared to plasma arc DED(PA-DED).Furthermore,there is a significant difference in the metallurgical mechanism between the two processes.In this study,we compared the geometry,microstructure,and mechanical properties of 316 L stainless steel deposited by L-DED and PA-DED processes.The underlying mechanisms of the difference in geometry,microstructure,and mechanical properties of samples printed by the two processes were discussed.Methods An in-house developed DED system that consists of a fiber laser with a maximum power of 6 k W,two robot arms,one L-DED module,and one PA-DED module was used.A 316 L stainless steel powder with a particle size ranging from 60 to 125μm was adopted as the feedstock for the two printing processes.Single tracks with a length of 80 mm were printed via the two processes,and their cross-sections were etched for geometry measurement.A quadratic regression orthogonal experiment was designed to investigate the effect of energy input,scanning velocity,and powder feeding velocity on the geometry of printed thin walls.The dimensions of the thin walls are 80 mm×3 mm×100 mm.The average layer width and height were measured from the middle location of the thin walls.The L-DED process parameters included a laser power of 2000 W,a scanning speed of 10 mm/s,and a powder feed rate of 24 g/min.The PA-DED process parameters included a current of 30 A,a scanning speed of 5 mm/s,and a powder feed rate of 12 g/min.Samples perpendicular to the build direction,parallel to the build direction,and inclined at 45°were machined for tensile testing.Microstructures of the printed t

关 键 词：激光技术 定向能量沉积 激光增材制造 等离子弧增材制造 316L不锈钢 

分 类 号：TN249[电子电信—物理电子学] TG444[金属学及工艺—焊接]