The preferred defect domain space for enhanced mechanical properties is a critical unknown in the selective laser melting (SLM) additive manufacturing community. This paper presents a systematic approach to relate mechanical properties and the microstructure in the keyhole and the lack of fusion domains for Ti-6Al-4V parts. SLM laser processing conditions were modified to generate three similar amounts of defects in the keyhole and lack of fusion domains. Material from each processing condition was scanned and quantified using x-ray computed tomography to map the defect size and distribution. Samples containing these resultant defects were compared in monotonic tension testing to determine the preferred defect domain for a given amount of defects. While it is known that high amounts of each type of defect is unfavorable, it is shown here that it is more favorable to be in the keyhole domain—at a similar amount of defects—than in the lack of fusion domain. This is attributed to not only the higher sphericity of the keyhole defects but also to the larger amount of crystallographic texture in the keyhole samples which has not been previously well established. Keyhole samples up to 6% porosity maintain yield and UTS values when compared to the stock samples with only a slight loss in elongation. In all cases, when the defect density increases the elongation is reduced. These findings illustrate the preferred location in the processing window for SLM Ti-6Al-4V parts that will be critical for ensuring optimal part performance.

在选择性激光熔化（SLM）增材制造行业中，用于增强机械性能的首选缺陷域空间是一个关键的未知领域。本文提出了一种系统的方法来关联锁孔中的力学性能和微观结构以及Ti-6Al-4V零件缺乏熔合域。修改了SLM激光加工条件，以在锁孔中产生三种相似数量的缺陷，并且缺乏融合域。使用X射线计算机断层扫描技术对每种加工条件下的材料进行扫描和定量，以绘制缺陷尺寸和分布图。在单调张力测试中比较包含这些最终缺陷的样品，以确定给定数量的缺陷的首选缺陷域。众所周知，每种类型的缺陷都是不利的，从这里可以看出，与没有融合区域相比，在钥匙孔区域（缺陷数量相似）更有利。这不仅归因于匙孔缺陷的球形度较高，而且归因于匙孔样品中大量的晶体织构，而以前尚未很好地建立这种晶体。与普通样品相比，孔隙率最高为6％的锁孔样品保持了屈服值和UTS值，而伸长率仅略有下降。在所有情况下，当缺陷密度增加时，伸长率降低。这些发现说明了SLM Ti-6Al-4V零件在加工窗口中的首选位置，这对于确保最佳零件性能至关重要。这不仅归因于匙孔缺陷的球形度较高，而且归因于匙孔样品中大量的晶体织构，而以前尚未很好地建立这种晶体。与普通样品相比，孔隙率最高为6％的锁孔样品保持了屈服值和UTS值，而伸长率仅略有下降。在所有情况下，当缺陷密度增加时，伸长率就会降低。这些发现说明了SLM Ti-6Al-4V零件在加工窗口中的首选位置，这对于确保最佳零件性能至关重要。这不仅归因于匙孔缺陷的球形度较高，而且归因于匙孔样品中大量的晶体织构，而以前尚未很好地建立这种晶体。与普通样品相比，孔隙率最高为6％的锁孔样品保持了屈服值和UTS值，而伸长率仅略有下降。在所有情况下，当缺陷密度增加时，伸长率就会降低。这些发现说明了SLM Ti-6Al-4V零件在加工窗口中的首选位置，这对于确保最佳零件性能至关重要。与普通样品相比，孔隙率最高为6％的锁孔样品保持了屈服值和UTS值，而伸长率仅略有下降。在所有情况下，当缺陷密度增加时，伸长率就会降低。这些发现说明了SLM Ti-6Al-4V零件在加工窗口中的首选位置，这对于确保最佳零件性能至关重要。与普通样品相比，孔隙率最高为6％的锁孔样品保持了屈服值和UTS值，而伸长率仅略有下降。在所有情况下，当缺陷密度增加时，伸长率就会降低。这些发现说明了SLM Ti-6Al-4V零件在加工窗口中的首选位置，这对于确保最佳零件性能至关重要。