层间冷却对激光增材制造TC17钛合金组织和拉伸性能的影响  

Effect of Interlayer Cooling on Structure and Tensile Properties of TC17 Titanium Alloy Fabricated by Laser Additive Manufacturing

作　　者：刘炳森 张述泉[1,2] 张纪奎 王华明 朱言言[1,2,3] Liu Bingsen;Zhang Shuquan;Zhang Jikui;Wang Huaming;Zhu Yanyan(Research Institute for Frontier Science,Beihang University,Beijing 100191,China;National Engineering Laboratory of Additive Manufacturing for Large Metallic Components,Beihang University,Beijing 100191,China;Ningbo Institute of Technology,Beihang University,Ningbo 315800,Zhejiang,China)

机构地区：[1]北京航空航天大学前沿科学技术创新研究院,北京100191 [2]北京航空航天大学大型金属构件增材制造国家工程实验室,北京100191 [3]北京航空航天大学宁波创新研究院,浙江宁波315800

出　　处：《中国激光》2022年第14期122-132,共11页Chinese Journal of Lasers

基　　金：国家科技重大专项(2017-Ⅶ-0006-0099);北航双一流引导专项基金(030810)。

摘　　要：定向能量沉积激光增材制造逐点逐层熔化堆积的工艺特点决定了工艺参数会对成形态钛合金构件的显微组织和力学性能产生显著影响,最终决定激光增材制造钛合金构件能否达到工程应用的性能要求。以先进航空发动机整体叶盘使用量较大的TC17近β型高强钛合金为研究对象,制备了两种不同层间冷却时间下的激光增材制造TC17钛合金构件,详细研究了层间冷却对成形构件晶粒形貌、显微组织和拉伸性能的影响,探究了热处理对组织演变及拉伸性能的影响。结果表明:随着层间冷却时间的增加,激光增材制造TC17钛合金的显微组织由双态组织转变为超细α片层网篮组织,β晶粒尺寸无显著变化,α相含量增加而片层宽度下降。连续成形试样具有良好的综合力学性能,其沿沉积增高方向的抗拉强度可达到1128 MPa,断后伸长率为10.5%,断口形貌为典型的韧性断裂;层间冷却时间增加会导致沉积态试样强度提高、塑性下降,断裂机制转变为解理脆性断裂。三重热处理可以改善层间冷却时间不同造成的组织和拉伸性能的差异,但难以获得优异的综合力学性能。Objective The process characteristics of directed energy deposition melting point by point and stacking layer by layer determining the core process parameters of laser additive manufacturing,such as laser power,scanning velocity,powder feeding rate,layer thickness,overlap rate,and scanning strategy,have a decisive impact on the microstructures and mechanical properties of the titanium alloy components fabricated by laser additive manufacturing,which finally decide whether the components could meet the performance requirements of engineering applications.This work takes the near-βTC17 high strength titanium alloy widely used in advanced aero-engine blisk as the research object.In the process of laser additive manufacturing,different positions of components inevitably experience different interlayer cooling time,which results in the difference of the temperature field distribution and the thermal cycle history.All these complex factors affect the structures and property characteristics of as-deposited components,even the microstructural evolution undergoes the subsequent heat treatment.However,as a key process parameter of laser additive manufacturing,the effect of interlayer cooling on the microstructures and mechanical properties of near-βhigh strength titanium alloys fabricated by laser additive manufacturing is not clear.This paper is committed to investigate the difference of microstructures and tensile properties of as-deposited TC17 titanium alloys experiencing different interlayer cooling time,and explore the internal variable rules contributing to the massive applications of laser additive manufacturing of TC17 blisk.Methods The LMD-V coaxial powder feeding laser forming system developed independently by our research group is used to melt the TC17 powder in which the surrounding argon inside is taken as the protective atmosphere and the rolled TC17 plate is used as the substrate.The relatively mature deposition process of high strength titanium alloys is selected to fabricate two thick plates with a geom

关 键 词：激光技术 激光增材制造 TC17 层间冷却 热处理 显微组织 拉伸性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]