Removal mechanism of double-diamond-abrasive-grinding GaN single crystals under graphene lubrication

Gallium nitride (GaN) is an advanced material used to manufacture chip wafers and high-power devices. Recently, grinding processing, has been applied in the fields of machinery manufacturing, aerospace, and medical devices as a highly efficient machining method. An in-depth understanding of the material removal mechanism produced by the double-grinding processes can provide guidance for the design of GaN-based nanodevices. Herein, molecular dynamics simulations were used to investigate the mechanism of removal of double-diamond-abrasive-grinding gallium nitride crystals under graphene lubrication, and a systematic study was performed to investigate the involved surface morphology, grinding force, stress distribution, and subsurface damage behavior. Results reveal that graphene can substantially enhance the wear resistance of GaN substrates by reducing surface wear, atomic displacement., potential energy, and subsurface damage, thereby playing a protective role toward the substrate. As the grinding depth increases, the grinding force and subsurface damage depth also increase. Furthermore, the effects of abrasive grain spacing on subsurface damage depth and phase change atoms were analyzed and found to have limited influence on material removal efficiency. These results deepen our understanding of material removal and protection mechanisms relative to substrates resulting from double-grinding processes as well as offer valuable insights for the rational design of abrasive wheels.