Additive manufacturing of magnesium (Mg) alloys has gained interest for the potential to fabricate complex geometries for extreme light-weighting or improved functionality. In this study, the effect of interlayer interval time and post-deposition processing (i.e., heat treatment and hot isostatic pressing (HIP)) on the microstructure and mechanical behavior of WE43 Mg specimens fabricated by laser powder directed energy deposition (LPDED) was investigated. Microstructure characterization was conducted using optical microscopy, scanning electron microscopy, scanning transmission electron microscopy, and energy dispersive X-ray spectroscopy. Mechanical behavior was evaluated using microhardness and uniaxial tensile testing. Post-processing resulted in improved yield strength, tensile strength, and ductility, which was attributed to a reduction in porosity and, to a lesser extent, the formation of second phase particles. The as-deposited specimens exhibited porosity below 3 pct and HIP treatment reduced porosity to below 0.1 pct. HIP specimens, processed with low interlayer interval time, exhibited the best combination of strength (~ 243 MPa tensile strength) and ductility (~ 9 pct elongation). Changes in interlayer interval time had limited impact on the grain size, hardness, or yield strength. However, increased interlayer interval time (~ 112 pct increase) caused a slight increase in gas porosity and dramatic reduction in tensile strength and ductility, which was attributed to the formation of lack-of-fusion defects in interlayer regions.

镁（Mg）合金的增材制造对制造复杂几何形状以实现极轻量级或提高功能性的潜力引起了兴趣。在这项研究中，层间间隔时间和沉积后处理的影响（即，热处理和热等静压（HIP）对采用激光粉末定向能量沉积（LPDED）制备的WE43镁试样的组织和力学性能进行了研究。使用光学显微镜，扫描电子显微镜，扫描透射电子显微镜和能量色散X射线光谱法进行微观结构表征。机械性能使用显微硬度和单轴拉伸测试进行评估。后处理可提高屈服强度，抗张强度和延展性，这归因于孔隙率的降低以及在较小程度上第二相颗粒的形成。如此沉积的样品显示出孔隙率低于3 pct，并且HIP处理将孔隙率降低至低于0.1 pct。HIP标本，层间间隔时间短，表现出强度（〜243 MPa拉伸强度）和延展性（〜9 pct伸长率）的最佳组合。层间间隔时间的变化对晶粒尺寸，硬度或屈服强度的影响有限。但是，增加的夹层间隔时间（增加〜112 pct）会导致气体孔隙率略有增加，抗张强度和延展性显着降低，这归因于在夹层区域中形成了熔合缺陷的缺乏。