Characterization of Composite Powder Feedstock from Powder Bed Fusion Additive Manufacturing Perspective

Abstract

This research aims at evaluating the characteristics of the 5 wt.% B4C/Ti-6Al-4V composite powder feedstock prepared by two different categories of mechanical mixing for powder bed fusion (PBF) additive manufacturing (AM) of metal matrix composites (MMCs). Microstructural features, particle size, size distribution, sphericity, conditioned bulk density and flow behavior of the developed powders were examined. The flowability of the regularly mixed powders was significantly lower than that of the Ti-6Al-4V powder. However, the flowability of the ball-milled systems was a significant function of the milling time. The decrease in the flowability of the 2 h ball-milled powder compared to the Ti-6Al-4V powder was attributed to the mechanical interlocking and the entangling caused by the B4C particles fully decorating the Ti-6Al-4V particles. Although the flattened/irregular shape of powder particles in the 6 h milled system acted to reduce the flowability, the overall surface area reduction led to higher flowability than that for the 2 h milling case. Regardless of the mixing method, incorporation of B4C particles into the system decreased the apparent density of the Ti-6Al-4V powder. The composite powder obtained by 2 h of ball milling was suggested as the best possible condition, meeting the requirements of PBF–AM processes.

Austenitic Stainless Steel Powders with Increased Nitrogen Content for Laser Additive Manufacturing

“…In general, a high circularity means good flowability of the powder. The spherical particles have less contact surface area, therefore the friction and interlocking between the particles is lower than that of the particles in irregular shape [28,30]. The nitrogen content in the feedstock (316L and modified 316L prepared by inductive melting and casting) is 200-300 ppm.…”

Role of powder particle size on laser powder bed fusion processability of AlSi10mg alloy

“…As shown in Figure 3, each complete test cycle contains downward and then the upward movement of a precision blade in a standard vessel accommodating the powder. The details of the FT4 test procedure and process variables can be found in [29].…”

“…The conditioned bulk density (CBD) of powders was also measured by the FT4 powder rheometer according to the procedure reported in [29]. For each sample, three measurements were performed, and the average value was reported as the CBD based on Eq.…”

“…Although the Hall flowmeter is known to be closer to the AM process (especially the powder fed techniques) than other conventional powder flowability measurement techniques, it has major limitations with evaluating the flowability of cohesive powders which are still good enough for powder bed fusion additive manufacturing (PBF-AM) processes [28]. Among various techniques currently available for the powder flowability measurement, the FT4 Freeman powder rheometer technique has been recommended since the interaction of the precision blade with the powder resembles that of the recoater/powder in the L-PBF process [29].…”

Morphological Evaluation of Tissue Reaction Response to the Titanium Implants for Cranioplasty. Experimental Study

“…Специальный валик выравнивает поданный порошок в ровный слой и удаляет излишний материал из камеры, после чего лазерная головка спекает частицы свежего порошка между собой и с предыдущим слоем согласно контурам, определенным цифровой моделью. После завершения вычерчивания слоя процесс повторяется: валик подает свежий материал, и лазер начинает спекать следующий слой [26]. Так слой за слоем формируется объект заданной формы.…”