激光功率与扫描速度对选区激光熔化钴铬合金组织性能的影响  

Effect of Laser Power and Scanning Speed on Microstructure and Properties of Co-Cr Alloy by Selective Laser Melting

作　　者：邓煜华 黎振华[1] 姚碧波 滕宝仁 李颢 DENG Yu-hua;LI Zhen-hua;YAO Bi-bo;TENG Bao-ren;LI Hao(School of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650500,China;School of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650500 [2]昆明理工大学机电工程学院,昆明650500

出　　处：《表面技术》2023年第1期325-335,共11页Surface Technology

基　　金：国家自然科学基金(51961017);云南省基础研究重点项目(202101AS070017);云南省重大专项(202103AN080001-002、202202AG050007-4);云南省重点研发计划(2018BA064)。

摘　　要：目的明确选区激光熔化钴铬合金中激光线能量密度、激光功率和激光扫描速度对成形件组织、性能的影响,探究优化工艺参数的方法。方法基于ANSYS有限元软件模拟选区激光熔化过程中熔池尺寸的基础上,通过金相显微镜分析了熔池尺寸和显微组织,电子背散射衍射分析了晶粒尺寸,使用力学试验机和洛氏硬度计研究了试样的力学性能。结果随着线能量密度降低,成形件的熔池尺寸、晶粒大小、冷却速度和力学性能降低。但在激光线线能量密度为0.242 J/mm的条件下,扫描速度为1200 mm/s时成形试样的致密度为98.7%,抗拉强度为867 MPa,延伸率为6.5%,其力学性能均高于扫描速度为950 mm/s时成形的试样,与线能量密度更高的0.263 J/mm成形条件下250 W+950 mm/s的成形试样力学性能相近。结论激光线能量密度是影响选区激光熔化钴铬合金熔池尺寸和组织性能的关键因素,但熔池尺寸与激光线能量密度没有线性关系。相同的线能量密度下,增加激光扫描速度,有利于获得大的熔池尺寸和冷却速度,提高成形件的致密度和降低晶粒尺寸,最终使成形件力学性能提高。It is an advanced manufacturing technology by direct metal laser melting.The important characteristic of the SLM technology is that it can produce parts with high geometrical dimensional accuracy,the forming parts have brilliant mechanical properties,and the relative density of the parts is close to 100%.However,the energy density cannot accurately reflect the relationship between scanning speed and molten pool size in process parameter optimization of SLM.This article studies the effect on SLM cobalt-chromium alloy of linear energy density and process parameter.Firstly,a suitable range of process parameters of linear energy density is selected,then the scanning speed is increased by fix the linear energy density for the process parameter optimization,and finally,the melt pool size is calculated by commercial finite element software ANSYS simulation under each process parameter to analyze the effect on process parameters of the molten pool size.The molten pool size obtained from the numerical simulation is analyzed to obtain the appropriate scan spacing,and the process parameters are imported into EOS m^(2)90 for specimens forming.The SLMed specimens are sandpapered and polished,and the porosity defects of the parts are observed by metalloscope,and the relative density of the parts are calculated by Imagepro software.After etch,the SLMed parts are analyzed by micrographs to determine the molten pool overlap and size under different process parameters.The variation of sub-cellular and grain size with process parameters is analyzed using FE-SEM and EBSD.The tensile strength and elongation of the SLMed specimens are tested by universal testing machine.The hardness of the SLMed specimens is tested using Rockwell hardness tester and five-point tests are collected to reduce the error.Finally,the cooling rate under different process parameters is analyzed by commercial ANSYS software again.Results showed that the molten pool size and the cooling rate decreased with the linear energy density,which result in inferior to r

关 键 词：Co-Cr合金 选区激光熔化 ANSYS有限元模拟 能量密度 熔池尺寸 力学性能 

分 类 号：V261.8[航空宇航科学与技术—航空宇航制造工程]