硒化锌晶体在红外成像与激光系统中有着广泛的应用，作为典型软脆性材料，其材料去除机理目前尚不清晰，获得超光滑表面仍极具挑战。文中采用槽切法研究刀具负前角对硒化锌晶体脆塑转变临界深度的影响。通过分析最大未变形切削厚度随切削参数变化规律，提出实现硒化锌晶体塑性域切削的理论模型。借助场发射扫描电子显微镜、白光干涉仪和拉曼光谱仪，系统分析了进给率对工件表面粗糙度、表面完整性及亚表面损伤的影响，提出表面缺陷形成机理，进而揭示硒化锌晶体材料去除机理。

ZnSe crystal has been widely used in infrared imaging and laser systems. However, as a typical soft-brittle material, the material removal mechanism in ultra-precision diamond turning process has not been clarified, it is still challenging to obtain nano-smoothed surface. In the study, the effect of tool ranke angle on ductile-brittle transition depth of ZnSe crystal have been investigated through novel plunge-cutting tests. The ductile regime machining model was revealed by comparing the maximum undeformed chip thickness and ductile-brittle transition depth. With the aid of FESEM, white light interferometer, and Raman spectrometer, the effect of feed rate on surface roughness, surface quality, phase transition and subsurface damage were systematically investigated. The surface defects formation mechanism was proposed. Furthermore, the material removal mechanism of ZnSe crystal in ultra-precision diamond turning process have been revealed.