Ni-Cr合金钎料激光钎焊金刚石表面金属化

为了研究激光钎焊金刚石磨粒表面金属化生成物类别与形成机制,采用第一性原理的密度泛函理论对常见碳化物进行了计算,并采用Ni-Cr合金钎料,借助光纤激光热源对金刚石磨粒进行了激光钎焊试验,获得了Cr 3C 2和Cr 7C 3两种碳化物的结构和力学性能参量以及金刚石磨粒表面微结构和碳化物种类。结果表明,Cr 3C 2和Cr 7C 3两者都具有金属性,且后者韧性更强;激光钎焊得到的金刚石磨粒与Ni-Cr合金钎料界面冶金反应层厚度约为4μm,金刚石磨粒表面碳化物主要为Cr 3C 2;超声辅助激光钎焊得到的金刚石磨粒表面碳化物为Cr 3C 2和Cr 7C 3,超声波高频振动可以促进界面反应,进而生成含碳量低的Cr 7C 3。此研究结果对激光钎焊金刚石技术的发展具有指导意义。

Metallization of diamond surface by laser brazing with Ni-Cr alloy filler

In order to study the types and formation mechanism of metallization products on diamond abrasive surface by laser brazing, the first-principle density functional theory was used to calculate the common carbides. Laser brazing experiments of diamond abrasives were carried out by means of Ni-Cr alloy filler metal and optical fiber laser heat source. The structure and mechanical properties of Cr₃C₂ and Cr₇C₃ carbides, as well as surface microstructures and carbide species of diamond abrasives, were obtained. The results show that both Cr₃C₂ and Cr₇C₃ are metallic, and the latter is tougher. The thickness of metallurgical reaction layer between diamond abrasives and Ni-Cr alloy brazing filler metal obtained by laser brazing is about 4μm. The surface carbides of diamond abrasives are mainly Cr₃C₂. The surface carbides of diamond abrasives obtained by ultrasonic-assisted laser brazing are Cr₃C₂ and Cr₇C₃. Ultrasound high frequency vibration can promote interfacial reaction, and then produce Cr₇C₃ with low carbon content. The research results have guiding significance for the development of laser brazing diamond technology.