Material removal and deformation mechanism in multiple nanoscratches of single crystal MgAl2O4

Abstract

Single crystal MgAl₂O₄ requires ultra-precision machining to achieve dimensional accuracy and surface quality due to its high hardness and brittleness. To investigate the effect of multi-abrasive scratch sequences on the material removal and deformation mechanism of single crystal MgAl₂O₄ in ultra-precision machining. Multiple nanoscratches experiments with different sequences were conducted to demonstrate the randomness of the scratch sequence occurrence at the abrasive tip in ultra-precision machining. The interactions between multiple nanoscratches with different sequences were analyzed for their effects on the material deformation characteristics and surface morphologies of single crystal MgAl₂O₄. Additionally, theoretical models for the penetration depth of multiple nanoscratches with different sequences were established. The results show that multiple nanoscratches with different sequences affect the material removal and deformation mechanism of single crystal MgAl₂O₄, and the predictions of the penetration depth theoretical model align closely with the experimental results. TEM analysis results show that the subsurface deformation mechanism in the ductile removal region during multiple nanoscratches is primarily characterized by the transformation of single crystals into poly-crystalline of nanocrystalline.