Processing Parameter Effects on Residual Stress and Mechanical Properties of Selective Laser Melted Ti6Al4V
Processing Parameter Effects on Residual Stress and Mechanical Properties of Selective Laser Melted Ti6Al4V
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DOI：
10.1007/s11665-018-3477-5
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发表时间：
2018-08-01
影响因子：
2.3
通讯作者：
Mumtaz, Kamran
中科院分区：
文献类型：
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作者：
Ali, Haider;Ghadbeigi, Hassan;Mumtaz, Kamran
选择性激光熔化 (SLM) 工艺的特点是温度梯度大，导致增材制造的金属结构内产生高水平的残余应力。 SLM 加工的 Ti6Al4V 由于快速凝固而产生马氏体微观结构，并导致延展性通常低于热加工等效材料。后处理热处理可应用于 SLM 部件，以消除内置残余应力并提高延展性。 SLM 零件的残余应力积累和机械性能可以通过改变 SLM 工艺参数来控制。本研究研究层厚度对 SLM Ti6Al4V 零件残余应力和机械性能的影响。这是首次研究不同功率和曝光以及保持能量密度恒定对 SLM Ti6Al4V 部件残余应力和机械性能的影响。研究发现，在相同能量密度下，降低功率和增加暴露量可降低残余应力并提高 SLM Ti6Al4V 零件的伸长率。增加层厚度会导致残余应力降低，但会损害机械性能。该研究基于详细的实验分析以及使用 ABAQUS 对过程进行有限元模拟，以了解过程的基础物理原理。
Selective laser melting (SLM) process is characterized by large temperature gradients resulting in high levels of residual stress within the additively manufactured metallic structure. SLM-processed Ti6Al4V yields a martensitic microstructure due to the rapid solidification and results in a ductility generally lower than a hot working equivalent. Post-process heat treatments can be applied to SLM components to remove in-built residual stress and improve ductility. Residual stress buildup and the mechanical properties of SLM parts can be controlled by varying the SLM process parameters. This investigation studies the effect of layer thickness on residual stress and mechanical properties of SLM Ti6Al4V parts. This is the first-of-its kind study on the effect of varying power and exposure in conjunction with keeping the energy density constant on residual stress and mechanical properties of SLM Ti6Al4V components. It was found that decreasing power and increasing exposure for the same energy density lowered the residual stress and improved the % elongation of SLM Ti6Al4V parts. Increasing layer thickness resulted in lowering the residual stress at the detriment of mechanical properties. The study is based on detailed experimental analysis along with finite element simulation of the process using ABAQUS to understand the underlying physics of the process.