  Diamond grit is widely used in cutting, grinding, and polishing tools for its
superior mechanical properties and performance in machining hard materials.
Selective laser brazing (SLB) of diamond grits is a new additive manufacturing
technique that has great potential to fabricate the next generation of
high-performance diamond tools. However, fundamental understanding and
quantitative analysis for the design and tuning of the SLB process and the
resulting bonding efficiency are not yet established as the process is
complicated by heating, fusion, wetting, solidification, grit migration,
bonding, reaction, and the interplay between these effects. We present a
thermodynamically consistent phase-field theoretical model for the prediction
of melting and wetting of SLB on diamond grits using a powder-based additive
manufacturing technique. The melting dynamics is driven by laser heating in a
chamber filled with argon gas and is coupled with the motion of multiple
three-phase contact lines. The relevant wetting dynamics, interfacial
morphology, and temperature distribution are computationally resolved in a
simplified 2D configuration.
