Damage evolution and removal behaviors of GaN crystals involved in double-grits grinding

Abstract

Understanding the complex interactions between the work material and abrasives is a difficult and hot topic during grinding of Gallium nitride (GaN) single crystals. In this work, molecular dynamics (MD) simulations of double-grits interacted grinding of GaN crystals were performed, and the grinding force, coefficient of friction, stress distribution, plastic damage behaviors, and abrasive damage were systematically investigated. The results demonstrated that interacted distance with both radial and transverse directions achieved better grinding quality than that with only one direction or single-grit grinding. The grinding force, grinding induced stress, subsurface damage depth, and abrasive wear increases as the transverse interacted distance increases. However, the influence laws of the interacted distance on atom number of phase transition and dislocation length are not distinct. Appropriate interacted distances between abrasives can decrease grinding force, coefficient of friction, grinding induced stress, subsurface damage depth, and abrasive wear during the grinding process. Grinding test combined with the cross-sectional TEM detection verified the reliability of the simulated damage behaviors, i.e. amorphous, high-pressure phase transition, dislocations, stacking faults, and lattice distortions. The results not only enhance the understanding of damage accumulation and material removal caused by the coupling actions of abrasives in grinding process, but also provide a feasible approach for the wheel design of ordered abrasives.

Accurate Measurement of Temperatures in Industrial Grinding Operations with Steep Gradients

“…In addition to experimental methods for measuring in-process grinding temperatures, molecular dynamics simulations also serve as an important tool for temperature analysis in mechanical machining processes [ 20 ]. Zhou et al [ 21 ] used molecular dynamics to simulate the material removal process during the abrasive machining of SiC substrates, revealing that the distribution and exposed height of abrasives influenced grinding temperatures and subsurface damage.…”

Chemical Mechanical Polishing for Monocrystal SiC Assisted by the Heterogeneous Sono-Fenton Oxidation

“…Due to the excellent physical properties, single crystal SiC has been one of the most important material in the high precision and cutting-edge fields, such as aerospace, rail transit, national defense and military industry, "new infrastructure," "carbon peak, carbon neutrality". [1][2][3][4] However, the inefficient ultra-precision polishing capability of single crystal SiC limited the the aforementioned application. As an epitaxial substrate, the surface of single crystal SiC needs to be smooth and non-destructive, for example, the roughness requires to be atomic level.…”