Fereiduni Eskandar, Ghasemi Ali, Elbestawi Mohamed
Department of Mechanical Engineering, McMaster University, Hamilton, ON L8S 4L7, Canada.
Materials (Basel). 2019 Nov 7;12(22):3673. doi: 10.3390/ma12223673.
This research aims at evaluating the characteristics of the 5 wt.% BC/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 BC 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 BC 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.
本研究旨在评估通过两种不同类型的机械混合制备的5 wt.% BC/Ti-6Al-4V复合粉末原料的特性,用于金属基复合材料(MMC)的粉末床熔融(PBF)增材制造(AM)。对所制备粉末的微观结构特征、粒度、粒度分布、球形度、条件堆积密度和流动行为进行了研究。常规混合粉末的流动性明显低于Ti-6Al-4V粉末。然而,球磨系统的流动性是球磨时间的显著函数。与Ti-6Al-4V粉末相比,2小时球磨粉末流动性的降低归因于BC颗粒完全包覆Ti-6Al-4V颗粒所引起的机械互锁和缠结。尽管6小时球磨系统中粉末颗粒的扁平/不规则形状会降低流动性,但总体表面积的减小导致其流动性高于2小时球磨的情况。无论混合方法如何,向系统中加入BC颗粒都会降低Ti-6Al-4V粉末的表观密度。通过2小时球磨获得的复合粉末被认为是最佳条件,满足PBF-AM工艺的要求。