Owing to the extreme hardness and toughness of sintered silicon nitride (Si₃N₄), the material is used in high stress and/or temperature applications such bearings, turbines, and combustion engines. Unfortunately, the same properties which make it ideal for use also make it particularly difficult to machine -- microcracks, inclusions and spalling are all common. While prior research has shown that it is possible to grind sintered Si₃N₄ without inducing surface damage so long as material is removed entirely under ductile flow, but grind forces associated with ductile Si₃N₄ material flow are so small as to render the material removal rate (MRR) impractical. Prior researchers have attempted to solve the MRR problem through laser-assisted machining. Laser ablation, by inducing a steep thermal gradient, weakens material through surface and subsurface cracks. Grinding of fractured weakened Si₃N₄ has been done at upwards of 50 % higher MRR. There are, however, issues with laser ablation, which prevent its widespread use. Laser ablation severely disrupts the microstructure of Si₃N₄. Because cracks propagate along and through grain boundaries, the irregular morphology makes accurately predicting crack growth from ablation and during subsequent grinding highly problematic. In this proof-of-concept work, researchers determined that it is possible to irradiation weaken Si₃N₄ without cracking it, and the material can be ground defect-free at a highly productive MRR. Findings suggest present laser-assisted machining methods which fracture weaken Si₃N₄ prior to grinding may not be the best way to maximize MRR.

Grinding of tungsten carbide with cobalt binder (WC-Co) requires a high amount of energy input for a low material removal rate (MRR) resulting in a high tendency for surface damage. Further reducing WC-Co grind productivity is frequent stoppages of the process for dressing to remove cobalt (Co) binder adhering to the abrasive. This proof-of-concept sought to solve all these problems through laser assisted machining (LAM). Laser parameters in this work were selected to impart sufficient energy to melt Co binder without impacting the WC lattice. Subsequent grinding in the heat affected zone (HAZ) was done defect-free at 7.6 mm³/min/mm. Nonirradiated samples were damaged at a fraction of this MRR. This was possible because binder melting and re-solidification reduced yield strength and improved ductility under load. Grazing Incidence X-ray Diffraction (GIXRD) confirmed full recovery of the original WC-Co structure under the HAZ. This work has the potential to significantly improve productivity machining WC-Co through laser assisted near net shape rough grinding.