Zinc selenide (ZnSe) crystal is difficult to cut due to its high brittleness. A better understanding of the material removal mechanism of ZnSe crystal is indispensable to help achieve a high-quality machined surface. In this paper, a theoretical model is first developed for analyzing the material removal behavior of brittle crystals during side-forward nanoscratching using the Berkovich indenter. The model correlates scratching parameters with scratch behavior parameters, morphology parameters, material removal modes, and material mechanical properties. To validate the model, the nanoindentation and side-forward nanoscratch tests of ZnSe crystal are carried out, and the effects of load and strain rate on the mechanical properties and scratch behavior of ZnSe crystal are investigated. The results show that the hardness decreases first and then stabilizes as the indentation load increases; the elastic modulus generally increases with the indentation load while it increases sharply at a very small strain rate. The results also show that with an increasing scratching normal load, the elastic recovery decreases first and then stabilizes while the friction coefficient increases slightly first and then stabilizes; with the increase of strain rate, the elastic recovery, scratching load, and friction coefficient decrease quickly at first and then increase by a similar power function. The model is proven to be applicable to determining the scratching load, friction coefficient, scratching depth, and elastic recovery with pile-up parameters, groove parameters, indenter orientation angle, and mechanical properties of ZnSe crystal, which has an average relative error of less than 14%. Furthermore, the effects of scratching direction on the scratching load and friction coefficient are discussed using the model. The results show that for side-forward scratching, the maximum normal load always occurs which is independent of the indenter orientation angle, while a relatively small friction coefficient exists. This research provides insights into the material removal behavior and mechanism in ultra-precision machining of ZnSe crystal.

硒化锌 (ZnSe) 晶体由于其高脆性而难以切割。更好地了解 ZnSe 晶体的材料去除机制对于帮助实现高质量的加工表面是必不可少的。在本文中，首先开发了一个理论模型，用于分析使用 Berkovich 压头在侧向纳米划痕过程中脆性晶体的材料去除行为。该模型将划痕参数与划痕行为参数、形态参数、材料去除模式和材料机械性能相关联。为了验证该模型，进行了 ZnSe 晶体的纳米压痕和侧向纳米划痕试验，研究了载荷和应变速率对 ZnSe 晶体的力学性能和划痕行为的影响。结果表明，随着压痕载荷的增大，硬度先降低后趋于稳定；弹性模量一般随压痕载荷的增加而增加，而在很小的应变率下则急剧增加。结果还表明，随着划伤法向载荷的增大，弹性回复率先减小后趋于稳定，摩擦系数先略微增大后趋于稳定；随着应变速率的增加，弹性回复率、划伤载荷和摩擦系数先快速下降，然后以相似的幂函数增加。该模型被证明适用于通过堆积参数、凹槽参数、压头取向角和 ZnSe 晶体的机械性能来确定划痕载荷、摩擦系数、划痕深度和弹性恢复，其平均相对误差小于 14%。此外，使用该模型讨论了刮擦方向对刮擦载荷和摩擦系数的影响。结果表明，对于侧向划痕，最大法向载荷始终出现，与压头取向角无关，同时存在相对较小的摩擦系数。这项研究为 ZnSe 晶体超精密加工中的材料去除行为和机制提供了见解。同时存在相对较小的摩擦系数。这项研究为 ZnSe 晶体超精密加工中的材料去除行为和机制提供了见解。同时存在相对较小的摩擦系数。这项研究为 ZnSe 晶体超精密加工中的材料去除行为和机制提供了见解。