Microstructure and mechanical characterization of TI6AL4V-B4C metal ceramic alloy, produced by laser powder-bed fusion additive manufacturing

Abstract

Increasing performance requirements of advanced products demands new, versatile fabrication techniques. Additive technology represents one of the most prospective fields of future production. B4C-based composites were fabricated on titanium substrate by selective laser melting (SLM) using titanium (Ti-6Al-4V) and boron carbide (B4C) powder mixture at different weight ratio (Ti:B4C = 1:0, 9:1, 8:2, and 7:3). It was shown that the use of a powder mixture В4С + Ti-6Al-4V with ceramic concentration of more than 10% of weight led to formation of cracks. The microstructure of composites was studied by optical and electron microscopy. It was shown that a heterogeneous structure was formed with regular allocation of zones inside each layer. It was established that new chemical compounds (TiB, TiB2, TiC) absent in the initial powder mixture were formed in the new structure. A significant change in microhardness is shown (for sample without ceramics—372 HV0.3, for sample 10% В4С + 90% Ti-6Al-4V—from 548 to 4214 HV0.3). It was shown that the wear loss of B4C-free sample is approximately 4.2 times higher than that of the sample with 10 wt% В4С.