剪切角理论是切削变形和摩擦的平衡方程，是切削最重要的理论之一。而现有经典剪切角理论提出于低速切削时代，并且是基于剪切滑移变形和刀-屑摩擦作用机制提出的，未考虑材料内外摩擦，导致现有理论模型预测高速切削剪切角时有明显误差，不能适应高速新趋势。因此本项目拟在材料内外摩擦作用机制下研究高速切削剪切角理论：构建基于剪切-冲压变形效应的高速切削材料内摩擦模型，进行材料剪切-冲压变形实验，获取各变形效应项；构建基于因素效应的高速切削材料外摩擦模型，进行材料高速高温外摩擦实验，获取各因素效应项；建立基于材料内外摩擦的高速切削粘结-滑动摩擦分界理论与刀-屑摩擦模型；在材料内外摩擦作用机制下构建高速切削剪切角理论；选用典型材料进行高速直角切削实验，验证所得的剪切角理论。本研究对于完善高速切削剪切角理论和阐明高速切削材料内外摩擦作用机制具有重要的科学意义和学术价值。

Shear angle theory is a balance equation between cutting deformation and friction, and is one of the most important cutting theories. Existing classical shear angle theories were proposed in the era of low speed cutting and under the action mechanism of shear, slide and Tool-chip friction, and did not reflect material internal and external friction. So the classical shear angle theories have obvious errors during predicting shear angle of High-speed cutting (HSC). So a new shear angle theory for HSC under the action mechanism of material internal and external friction will be constructed in this proposal. A material internal friction model will be built up based on shear and pressure deformation effects which can be obtained through shear and pressure deformation experiments. Based on factor effects which can be measured through high speed external friction experiments, a material external friction model will be proposed. Based on material internal and external friction, a Tool-chip friction model and a model of adhensive-sliding friction boundary will be built up. To sum up three proposed friction models, a new shear angle theory for HSC will be constructed. The shear angle theory will be verified by experimental results of HSC of typical materials. This study has important scientific significances and academic values for improvement of HSC shear angle theory and revealing mechanisms of material internal and external friction.