分析了残余剪应力对材料硬度的影响，导出了残余剪应力与硬度压头下最大剪应力的关系式．分析表明，残余剪应力与残余正应力不同，无论其方向如何，总是使材料硬度下降．通过实验证明，陶瓷／硬质合金热压复合片界面附近，残余剪应力使硬度下降的值大于由于残余压应力使硬度升高的值．据此分析认为，当陶瓷层热膨胀系数比硬质合金层小，而且太薄时，虽然可以在陶瓷层形成较大的残余压应力，但因残余剪应力的影响，表层的硬度不仅不会升高，反而会降低． The effect of residual shear stress on the hardness of the material is analyzed, and the relationship between the residual shear stress and the maximum shear stress under the hardness head is derived. The analysis shows that the residual shear stress is different from the residual normal stress and the hardness of the material is always decreased regardless of the direction. The experiment proves that the value of the residual shear stress in the vicinity of the interface between the ceramic / cemented composite sheet and the hot-pressed composite sheet decreases the hardness more than the hardness caused by the residual compressive stress. Based on this analysis, when the ceramic layer thermal expansion coefficient smaller than the cemented carbide layer, and too thin, although the ceramic layer can form a larger residual compressive stress, but the residual shear stress, the surface hardness not only does not rise High, but will be reduced.