SLM成形TC4钛合金高温拉伸力学性能及断裂机制分析  

High-temperature Tensile Properties and Fracture Morphology Analysis of TC4Titanium Alloy Formed by Selective Laser Melting

作　　者：肖美立[1] 柯林达[1] 赖彩芳 窦恩惠 杜磊 Xiao Meili;Ke Linda;Lai Caifang;Dou Enhui;Du Lei(Shanghai Spaceflight Precision Machinery Institute,Shanghai Engineering Research Center of Near-Net-Shape Forming for Metallic Materials,Shanghai 201600,China)

机构地区：[1]上海航天精密机械研究所,上海金属材料近净成形工程技术研究中心,上海201600

出　　处：《应用激光》2021年第2期350-356,共7页Applied Laser

基　　金：上海市“科技创新行动计划”基础研究重点科技项目(17JC1402600);国家自然科学基金资助项目(51701116);上海市青年科技启明星计划(19QB1402000)。

摘　　要：研究了选区激光熔化(SLM)成形TC4钛合金室温拉伸及高温拉伸力学性能和微观组织,以及高温拉伸断口形貌和气孔形成原因。结果表明:SLM成形TC4钛合金沉积态试样性能呈现强度高而塑性低的特点;经过800℃、4h真空退火处理后,室温拉伸力学性能达到同牌号锻件水平。在400℃、500℃和600℃高温拉伸条件下,沉积态试样高温抗拉强度Rm相较于退火态试样平均高出24.7%、27.9%及8.3%,而沉积态试样断后伸长率A相对较低;但在600℃条件下沉积态试样平均断后伸长率达到了45.5%,比退火态试样高出近一倍。退火态试样高温拉伸断口附近存在大量密集分布的气孔,气孔首先沿晶界形成,随后在拉伸变形过程中,由于试样发生颈缩变形,气孔随变形向断口部位形成聚集现象。The microstructure and tensile properties in the conditions of room-temperature and high-temperature,and the reasons of fracture morphology and porosity formation in high temperature tensile fracture about TC4titanium alloy formend by selective laser melting have been investigated.The results show that the room temperature tensile properties of the TC4alloy without heat treatment characterized by high strength and low shaping.After the 800℃,4hvacuum annealing,the properties of TC4alloy reached the level of forging pieces of the same brand.Under the tensile conditions at 400℃,500℃,600℃,strength of the deposited samples is higher than that of annealed samples on average of 24.7%,27.9%,8.3%.But the elongation of the deposited samples is lower,excepting the average elongation achieved 45.5%under 600℃for the deposited samples,which has been nearly twice comparing with the annealed sample.Numerous densely distributed pores existed at the fracture place about annealed samples employing by high-temperature tensile.The pores were first formed at grain boundaries,and then in the process of high temperature tensile deformation,due to the necking deformation of the sample,the pores accumulated to the fracture site along with the deformation.

关 键 词：激光选区熔化 TC4钛合金 高温拉伸 力学性能 断裂形貌 

分 类 号：TG166.5[金属学及工艺—热处理]