Ultra-precision diamond turning of ZnSe ceramics: Surface integrity and ductile regime machining mechanism

• DOI: 10.1016/j.infrared.2021.103706
• Publication Date: 2021-03-20T04:48:40Z
• Authors: Ruiwen Geng; Xiaojing Yang; Qiming Xie; Wanqin Zhang; Jie Kang; Yueqin Liang; Rui Li
• Keywords: Brittleness; Surface Integrity; Deformation mechanism

Abstract ZnSe ceramics has extensive applications in infrared imaging and laser systems. However, as a soft–brittle optical material, the mechanism of material removal and surface defects formation in ultra-precision diamond turning have not been clarified. In the present study, novel taper cutting tests were conducted to determine the ductile–brittle transition depth. Furthermore, the precondition for achieving ductile mode machining was revealed by comparing the maximum undeformed chip thickness and ductile–brittle transition depth. The effect of feed rate on surface roughness, surface quality, phase transition, and subsurface damage were systematically investigated. With the aid of cross-sectional TEM, the material removal mechanism in the ductile regime was revealed first, and the results indicated the formation of high-density dislocations, stacking faults, and deformation twins coordinating to promote ductile deformation. The study has provided insight into ductile regime machining mechanisms of ZnSe ceramics in the ultra-precision diamond turning process.