聚晶金刚石刀具高频感应钎焊热损伤研究

Research on Thermal Damage of Polycrystalline Diamond Tools During Hi-frequency Induction Brazing

基于工程实践设计了聚晶金刚石(PCD)刀具的钎焊试验,研究其热损伤形式并分析热损伤机理。结果表明:PCD刀具热损伤形式包括凹坑、凸起和裂纹,其中凹坑为最主要的热损伤形式;钎焊过程中,PCD刀具未发生石墨化转变;钴与其氧化物部分脱落,钴氧化物与金刚石润湿性差以及焊接拉应力是导致热损伤产生的主要原因。随着钎焊温度和恒温时间的增加,热损伤程度加剧。本文提出一种评价PCD刀具热损伤程度的方法,即基于机器学习的图像识别凹坑面积法,该方法能够定量表征热损伤程度。

Based on the engineering practice,the brazing experiment of polycrystalline diamond(PCD)tools is designed.The form and mechanism of thermal damage are studied.The thermal damage forms of PCD tools include pit,bulge and crack,of which pit is the most preponderant thermal damage form.Graphitization of PCD tools doesn′t occur during brazing.Part of cobalt and its oxides fall off,the bad wettability between cobalt oxides and diamond,and welding tensile stress result in thermal damage.The results show that the increase of brazing temperature and constant time exacerbate the degree of thermal damage.A method for evaluating the degree of PCD tools′thermal damage which image recognition pit area method based on machine learning is proposed,and it can quantitatively characterize the degree of thermal damage.