In situ formed TiB2/TiC complex structure in laser-alloyed coatings with improved wear property

Laser-alloyed composite coatings were fabricated on Ti–6Al–4V by using Ni60A + micro-sized B4C particles as the precursor material. The composite coatings were mainly comprised of a kind of TiB2/TiC complex structure, assembled by TiB2 lamellae and TiC pillars. In this study, the formation mechanism of the TiB2/TiC complex structure was discussed intensively. TiB2 lamellae were firstly precipitated from the melt pool. Subsequently, TiC particles nucleated heterogeneously and grew on the TiB2 plates. The nucleation and growth of TiB2 and TiC proceeded synchronously, further forming the TiB2/TiC complex structure. The composite coating fabricated under a moderate scan velocity (450 mm⋅min−1) exhibited a good combination of high micro-hardness and wear resistance.