基于无量纲工艺图的激光熔化沉积制备Ti6Al4V工艺与性能研究  

Process and Properties of Ti6Al4V Manufactured using Laser Melting Deposition with Dimensionless Processing Diagram

作　　者：候静宇 李正阳[1] 蒋华臻 姚少科 Hou Jingyu;Li Zhengyang;Jiang Huazhen;Yao Shaoke(Lab of Mechanics in Advanced Manufacturing,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;School of Engineering Science,University of Chinese Academy of Scieyices,Beijing 100049,China)

机构地区：[1]中国科学院力学研究所先进制造工艺力学实验室,北京100190 [2]中国科学院大学工程科学学院,北京100049

出　　处：《中国激光》2022年第2期135-146,共12页Chinese Journal of Lasers

摘　　要：如何高效获取合适的工艺参数进行激光熔化沉积(LMD)制造高性能零件是一项艰巨的挑战。提出了一种有效进行参数选择的方法,建立了基于LMD工艺的无量纲参数组,利用文献中获取的LMD工艺数据构建无量纲工艺图,确定了本试验LMD制备Ti6Al4V的工艺范围。利用正交试验研究了不同激光功率q、扫描速率v和扫描间距h组合下的无量纲等效能量密度E;对LMD制备Ti6Al4V块状试样组织和性能的影响。结果表明,LMD制备的试样呈现出明显的柱状晶外延生长特点,柱状晶的宽度随E;增加而增大。在通过无量纲工艺图确定的最优参数E_(0)^(*)=3.74下LMD制备的Ti6Al4V试样无熔合缺陷,硬度为391.7 HV,抗拉强度为963 MPa,延伸率为13.4%。结果表明,利用构建的无量纲工艺图缩小工艺参数范围,可以获得综合力学性能优良的样件。Objective Laser melting deposition(LMD) enables the generation of complex-shaped or customized parts that can be used in various engineering applications. The ultimate mechanical behavior of metallic parts is related to their thermal-history-dependent microstructure. To control their microstructure and resultant mechanical properties, understanding and predicting their thermal history during the layer-wise manufacturing is critical. Therefore, many research efforts have focused on determining the effects of process parameters on the microstructure and mechanical properties of LMD parts. However, obtaining optimal processing parameters for LMD to realize high-performance parts is challenging because the quality of these parts is affected by many parameters in the process. Few systematic attempts have been made to relate these parameters via characterizing underlying physical processes. In this paper, we propose a novel processing parameter screening strategy with a dimensionless processing diagram. Such a diagram defines a set of appropriate operating regions for LMD using identified dimensionless groups of processing parameters. The diagram provides a useful reference and methodology to aid the selection of appropriate processing parameters during the initial development stages.Methods To optimize processing parameters, we combined the approaches of dimensionless processing diagram and orthogonal design. Several key dimensionless processing parameters were derived considering the temperature field to describe LMD. Scattered processing parameters of different types of materials for LMD taken from the literature were normalized against material thermophysical properties and presented on the dimensionless processing diagram. The diagram presented isopleths of normalized equivalent energy density E_(0)^(*) and provided general process windows for a range of alloys. The orthogonal design was used to further narrow the processing window. Ti6 Al4 V samples were fabricated using LMD in a helium environment. The grain mor

关 键 词：激光技术 TI6AL4V 激光熔化沉积 无量纲工艺图 微观组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG146.3[金属学及工艺—金属材料]