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

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.