激光焊接齿科CoCr-NiCr异种合金组织结构研究

Study of microstructure of laser welded dento-prosthetic CoCr-NiCr alloy

选用齿科烤瓷用NiCr合金和支架用CoCr合金,利用脉冲Nd-YAG激光,在不同电压下进行焊接,考察焊件力学性能,优选电压条件,研究此条件下焊件熔焊区及其附近区域化学成分、显微组织变化规律。结果表明,适合齿科临床应用焊接电压为280V,此条件下可以得到显微组织致密、细小的熔焊区,熔焊区与两侧母材呈冶金结合,主要成分为Ni元素,以固溶体和化合物形式存在;Co、Cr元素部分溶入固溶体,部分与Mo、Be形成化合物。焊接中冶金过程充分,无新相生成。双向侧吹氩气可以对熔焊区起到良好的保护作用,无氧化物形成。

NiCr alloy and CoCr alloy for dento-prosthetie operation were welded by a pulse Nd-YAG laser under various voltages to estimate the mechanical performance of the weld and select the best voltage parameters. The chemical composition and mierostrueture of fusion zone and wdd heat affected zone were investigated. The results show that the welding voltage which is suitable to clinic appliance is 280V, and a fine grained mierostrueture of the fusion zone is observed in this voltage condition. Moreover, the fusion zone and the parent alloy exhibit metullurgieal bending and the major composition Ni exists in solid solution and compound. The element Co and Cr are partly dissolved in solid solution and partly to form compound with Mo and Be. No new phase is examined during welding. Argon used in welding can protect the fusion zone and avoid forming oxide.