Although different types of powder feedstock are used for additive manufacturing via laser powder bed fusion (L-PBF), limited work has attempted to directly compare the microstructure and mechanical behavior of components manufactured from those powder feedstock. This work investigated the microstructure, phase composition, melt pool morphology, and mechanical properties of a prealloyed Ti-35Nb alloy manufactured using L-PBF and compared these to their counterparts produced from elemental powder mixture. The samples manufactured from the powder mixture are composed of randomly distributed undissolved Nb in the α/β matrix, resulting from the unstable melt pool during the melting of the powder mixture. By contrast, parts produced from prealloyed powder display a homogeneous microstructure with β and α″ phases, owing to the full melting of prealloyed powder, therefore, a more stable melt pool to achieve a homogeneous microstructure. The Ti-35Nb manufactured from prealloyed powder exhibits large tensile ductility (about 10 times that of the counterparts using mixed powder), attributed to the high homogeneity in microstructure and chemical composition, strong interface bonding, relatively low oxygen content, and the existence of a large amount of β phase. This work sheds insights into understanding the effect of powder feedstock on the melt pool stability therefore the microstructure and mechanical behavior of the resultant parts.

尽管通过激光粉末床融合 (L-PBF) 将不同类型的粉末原料用于增材制造，但尝试直接比较由这些粉末原料制造的部件的微观结构和机械行为的工作有限。这项工作研究了使用 L-PBF 制造的预合金 Ti-35Nb 合金的微观结构、相组成、熔池形态和机械性能，并将这些与由元素粉末混合物制成的对应物进行了比较。由粉末混合物制成的样品由 α/β 基体中随机分布的未溶解 Nb 组成，这是由粉末混合物熔化过程中不稳定的熔池造成的。相比之下，由预合金粉末制成的零件显示出具有 β 和 α" 相的均匀微观结构，由于预合金粉末完全熔化，因此熔池更稳定，从而实现均匀的微观结构。由预合金粉末制成的 Ti-35Nb 具有较大的拉伸延展性（约为使用混合粉末的同类材料的 10 倍），这归因于微观结构和化学成分的高度均匀性、强界面结合、相对较低的氧含量以及存在的大量的β相。这项工作有助于了解粉末原料对熔池稳定性的影响，从而了解所得零件的微观结构和机械性能。归因于显微结构和化学成分的高度均匀性，界面结合力强，含氧量相对较低，以及大量β相的存在。这项工作有助于了解粉末原料对熔池稳定性的影响，从而了解所得零件的微观结构和机械性能。归因于显微结构和化学成分的高度均匀性，界面结合力强，含氧量相对较低，以及大量β相的存在。这项工作有助于了解粉末原料对熔池稳定性的影响，从而了解所得零件的微观结构和机械性能。