Ti-5Al-5Mo-5V-3Cr (Ti-5553), a near-β Ti alloy, possesses an excellent combination of strength, toughness, and strength-to-weight ratio, and due to its poor machinability characteristic, it is poised to be additively manufactured for key structural applications. This study examines the micro-/defect-structure and mechanical behavior, including both tensile and fatigue, of laser powder bed fused Ti-5553. The tensile and fatigue specimens are fabricated in two locations on the build plate with respect to the powder feed direction, i.e., west (away from powder reservoir) and east (near powder reservoir), to examine the location dependence of the mechanical properties. In addition, fatigue specimens are furnished in both un-machined and machined surface conditions. It is found that the volumetric defect content is higher for the west specimens than the ones in the east; however, tensile and fatigue properties are not affected by part location. The insensitivity of fatigue lives to the part location can be ascribed to specimens having statistically equivalent defect size distribution near the surface, as fatigue failures are primarily initiated by critical defects on or in the vicinity of the surface in un-machined and machined specimens.

中文翻译：

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增材制造的 Ti-5Al-5V-5Mo-3Cr：了解缺陷-疲劳关系


Ti-5Al-5Mo-5V-3Cr (Ti-5553) 是一种近β Ti 合金，具有优异的强度、韧性和强度重量比组合，但由于其切削加工性较差，因此在针对关键结构应用进行增材制造。本研究检查了激光粉末床熔融 Ti-5553 的微观/缺陷结构和机械行为，包括拉伸和疲劳。拉伸和疲劳样本在构建板上相对于粉末供给方向的两个位置制作，即西侧（远离粉末储存器）和东侧（靠近粉末储存器），以检查机械性能的位置依赖性。此外，还提供了未加工和加工表面条件下的疲劳样本。结果发现，西部试件的体积缺陷含量高于东部试件；然而，拉伸和疲劳性能不受零件位置的影响。疲劳寿命对零件位置的不敏感性可归因于表面附近具有统计上相等的缺陷尺寸分布的样本，因为疲劳失效主要是由未加工和加工样本中表面上或表面附近的关键缺陷引发的。