4H-SiC is a typical difficult-to-machine semiconductor due to its high hardness and anisotropy. Conventional abrasive machining is limited by subsurface damage (SSD) and tool wear. Thermally assisted machining offers advantages, but achieving thermal-mechanical coupling remains experimentally challenging. This study established a molecular dynamics (MD) model featuring synchronized contact between the heating zone and abrasive grains—simulated along the [<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\overline{1}2\overline{1}0$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>2</mn> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>0</mn> </mrow> </math></EquationSource> </InlineEquation>] crystal direction. The surface thermal power densities (Ps) were varied to investigate damage evolution, chip-debris morphology, machining forces, sliding friction coefficient (μ), dislocations, and SSD depth. Compared with conventional abrasive machining, at a critical Ps of 12.0 × 1011 W/cm2, μ, weighted mean of von Mises stress (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\overline{\sigma }_{vm}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover> <mi>σ</mi> <mo>¯</mo> </mover> <mrow> <mi mathvariant="italic">vm</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>), and SSD depth decrease by 49.0, 28.3, and 67.6%, respectively. Sufficient thermal softening results in a <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\overline{\sigma }_{vm}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover> <mi>σ</mi> <mo>¯</mo> </mover> <mrow> <mi mathvariant="italic">vm</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> reduction in the deformation zone, which promotes plastic flow and surface amorphization. Energy dissipation is confined to the near-surface region, suppressing SSD propagation. This study provides atomic-scale insights for optimizing thermally assisted parameters to minimize SSD.

Molecular Dynamics Simulation Investigation of Thermal Assistance Effects in Synchronous Thermally Assisted Scratching of Monocrystalline 4H-SiC

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发表日期：

2026年4月25日

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Siwei Xia,
Zhidong Liu

摘要

4H-SiC is a typical difficult-to-machine semiconductor due to its high hardness and anisotropy. Conventional abrasive machining is limited by subsurface damage (SSD) and tool wear. Thermally assisted machining offers advantages, but achieving thermal-mechanical coupling remains experimentally challenging. This study established a molecular dynamics (MD) model featuring synchronized contact between the heating zone and abrasive grains—simulated along the [ $\overline{1}2\overline{1}0$ $\bar{1} 2 \bar{1} 0$ ] crystal direction. The surface thermal power densities (P_s) were varied to investigate damage evolution, chip-debris morphology, machining forces, sliding friction coefficient (μ), dislocations, and SSD depth. Compared with conventional abrasive machining, at a critical P_s of 12.0 × 10¹¹ W/cm², μ, weighted mean of von Mises stress ( $\overline{\sigma }_{vm}$ ${\bar{σ}}_{vm}$ ), and SSD depth decrease by 49.0, 28.3, and 67.6%, respectively. Sufficient thermal softening results in a $\overline{\sigma }_{vm}$ ${\bar{σ}}_{vm}$ reduction in the deformation zone, which promotes plastic flow and surface amorphization. Energy dissipation is confined to the near-surface region, suppressing SSD propagation. This study provides atomic-scale insights for optimizing thermally assisted parameters to minimize SSD.