【摘要】 PCD刀具高速切削时温度有时高达800～1 000℃,刀具材料元素的扩散有可能对PCD刀具的磨损产生重要影响.为此,从热力学角度研究了PCD刀具的扩散磨损规律,利用热力学理论求出了碳元素在铝中的活度,推导出了金刚石刀具中碳元素在工件材料铝中的溶解度模型,在该热力学模型基础上用Matlab计算出不同温度下PCD刀具加工铝合金时刀具材料元素扩散溶入工件材料中的浓度值.结果表明,刀具材料元素在工件材料中的扩散以指数函数的形式发生,随着切削温度的升高略有降低,变化平稳.XPS测试还表明,金刚石刀具中的碳元素与工件材料中的硅元素发生化学反应生成了硬度很高的碳化硅,对刀具的磨损产生影响.研究结果可对刀具材料的研究和设计提供参考,并可实现对刀具磨损状态的预报.更多还原

【Abstract】 Cutting temperature sometimes highly reaches 800—1.000 ℃ at high speed cutting aluminum alloy with PCD tools,and diffusion of material element of tools may have important influence on PCD tools wear at such high temperature.In this paper,the rules of diffusion wear for PCD tools were studied based on thermodynamics.Firstly,the activity of carbon in aluminum was calculated based on thermodynamical theory.Then the dissolution concentration model of carbon in aluminum was deduced.At last,the dissolution concentrations of carbon in aluminum of PCD tools at different temperatures were calculated with Matlab.Results show that the diffusion rules occur in the form of exponential function,which decrease slightly with the increase of cutting temperature,and the XPS results also indicate that the carbon element in diamond tools has reacted with the silicon element in workpiece and the reaction produces silicon carbide with high hardness which may probably affects the tool wear.It is found that the theoretical results are consistent with the experimental data,which can provide references for tool material design and selection,and may also predict the tool wear.更多还原