选区激光熔化成形TiC/TC4复合材料的工艺参数与组织演变研究  

Parameters and Microstructure Evolution of TiC/TC4 Composites Formed by Selective Laser Melting

作　　者：黄宏康 罗霞 戴玉宏 何鑫 刘允中 黄本生[1] 范舟[1] Huang Hongkang;Luo Xia;Dai Yuhong;He Xin;Liu Yunzhong;Huang Bensheng;Fan Zhou(School of New Energy and Materials,Southwest Petroleum University,Chengdu 610500,Sichuan,China;Chengdu Xinshan Aerospace Technology Co.,Ltd.,Guangzhou 510640,Guangdong,China;National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials,South China University of Technology,Chengdu 610500,Sichuan,China)

机构地区：[1]西南石油大学新能源与材料学院,四川成都610500 [2]华南理工大学国家金属材料近净成形工程技术研究中心,广东广州510640 [3]成都新杉宇航科技有限公司,四川成都610500

出　　处：《中国激光》2024年第16期155-167,共13页Chinese Journal of Lasers

基　　金：广东省重点领域研发计划项目(2019B090907001);四川省重点研发计划项目(2020YFH0151)。

摘　　要：钛基复合材料具有高弹性模量、高比强度、高耐磨性和优异的高温耐久性等特点,在航空航天领域有良好的应用前景。采用低能球磨制备了纳米TiC颗粒与TC4的复合粉体,然后使用选区激光熔化(SLM)制备了TiC/TC4钛基复合材料,分析了不同体能量密度(29~97 J/mm^(3))对复合材料成形质量、显微组织、显微硬度的影响,并总结了组织演变机理和TiC演变过程。结果表明,成形该复合材料的最佳体能量密度为50~70 J/mm^(3),在该范围内试样的最高相对密度可达99.7%,显微硬度为385~392 HV。横截面上,显微组织的晶粒呈特殊的双尺寸分布,即由初生β等轴晶和沿其外围生长的不规则共晶区组成;纵截面上,显微组织呈鱼鳞状形貌分布且熔池内存在大量流纹状组织。复合材料中存在未溶TiC(主要分布于初生β晶界附近)、共晶TiC(主要呈链状网络分布于共晶β晶界)以及沉淀析出TiC(主要呈颗粒状分布于晶粒内)。随着体能量密度的增加,链状共晶TiC向棒状转变,晶内TiC尺寸长大。共晶TiC与β-Ti没有取向关系,共晶TiC、沉淀析出TiC与α'-Ti均存在明显取向关系,即{11-20}α'-Ti//{110}TiC。Objective Titanium matrix composites have attracted considerable attention because of their high modulus of elasticity,high specific strength,high wear resistance,and excellent high-temperature durability.Most studies on titanium matrix composites(TMCs)focus primarily on the in-situ formed TiC reinforced composites.However,few studies have focused on the direct addition of TiC-reinforced titanium matrices.The manners in which the size,morphology,and distribution of TiC evolve during the SLM process and how they affect the microstructure and mechanical properties remain unclear.In this study,TiC/TC4 composites with directly added nanoscale TiC particles are successfully prepared by selective laser melting(SLM),and the microstructure evolution under different volume energy densities is investigated.Further,the TiC evolution during SLM and its influence on the microstructure and microhardness are analyzed.Thus,the findings of this study can provide the support for SLM preparation of titanium composites.Methods Herein,nanoscale TiC(diameter of 50-150 nm)and TC4 are selected as the reinforced phase and matrix,respectively.The composite powder with TiC uniformly embedded on the surface of the TC4 powder is obtained by low-energy ball milling.Subsequently,the TiC/TC4 composites are prepared via SLM with different volume energy densities(29-97 J/mm~3).The forming quality and microstructures at different volume energy densities are observed using optical microscopy(OM)and scanning electron microscopy(SEM)equipped energy disperse spectroscope(EDS).The grain size and crystal orientation are investigated using electron backscattering diffractometer(EBSD),and the phase compositions are measured using X-ray diffraction(XRD).Finally,the microhardness is measured using a digital microhardness tester.Results and Discussions The optimized volume energy densities for the SLM formed TiC/TC4 composites are in the range of 50-70 J/mm~3,with a relative density of 99.7%(Fig.3).Owing to the enrichment of TiC in the melt pool boundary zon

关 键 词：激光技术 钛基复合材料 选区激光熔化 显微组织演变 TiC演变 

分 类 号：TB331[一般工业技术—材料科学与工程]