Abstract The mechanical performance of surface-modified layers is important during mechanical-component service. A simpler expression to characterize the carbon content of the surface-modified layers was proposed for alloy steel after carburizing. The tensile test method was used to determine the elastic–plastic properties of the surface-modified layers of the 18CrNiMo7-6 carburized alloy. The hardness of all tensile test specimens was determined and the relationship with the carbon content was given. The elastic modulus, yield strength and hardening exponents were obtained for the surface-modified layer from the tensile test and stress–strain curves. The elastic modulus does not change with depth, whereas the yield strength and hardening exponent decreased gradually along the depth and were almost correlated with the carbon distribution. The hardening exponent model of the surface-modified layer was given as an exponential function. The relationship between elastic modulus, yield strength, hardening exponent and hardness agrees broadly with the modified expanding cavity model for the surface-modified layer of 18CrNiMo7-6 carburized alloy.

中文翻译：

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渗碳引入表面改性层的弹塑性特性

摘要 表面改性层的机械性能在机械部件服役过程中具有重要意义。对于渗碳后的合金钢，提出了一种更简单的表征表面改性层碳含量的表达式。拉伸试验方法用于确定 18CrNiMo7-6 渗碳合金表面改性层的弹塑性性能。测定了所有拉伸试样的硬度，并给出了与碳含量的关系。从拉伸试验和应力-应变曲线获得表面改性层的弹性模量、屈服强度和硬化指数。弹性模量不随深度变化，而屈服强度和硬化指数沿深度逐渐降低，几乎与碳分布相关。表面改性层的硬化指数模型以指数函数形式给出。弹性模量、屈服强度、硬化指数和硬度之间的关系与18CrNiMo7-6渗碳合金表面改性层的修正膨胀腔模型基本吻合。