钛合金与铬青铜电子束自熔钎焊接头组织与力学性能

Microstructure and Mechanical Property of Electron Beam Self-Melting Brazing Joint of Titanium Alloy to Chromium Bronze

摘要:

采用铜侧偏束工艺实现了TA15钛合金与QCr0.8铬青铜的电子束自熔钎焊，采用光学显微镜、扫描电子显微镜和X射线衍射分析仪对焊缝组织进行了分析，通过接头抗拉强度对接头力学性能进行了评价。结果表明，电子束偏向铜合金1 mm时，钛合金母材只有上部少量熔化，实现与铜合金的连接，而接头中部和下部的连接则通过液态金属对钛合金母材的钎接而实现连接。钎缝界面由较薄的Ti-Cu化合物层组成，主要包括TiCu、Ti2Cu3、TiCu2和TiCu4。而在铜侧焊缝内，细小的Ti-Cu化合物弥散分布于铜基固溶体上，使焊缝得到强化。接头强度达到300 MPa，拉伸时断裂发生在铜合金上，呈韧窝状塑性断裂模式。

Abstract:

Electron beam self-melting brazing experiments of TA15/QCr0.8 dissimilar metals with a copper side beam offset were carried out. Microstructure of the weld was examined by optical microscopy and scanning electron microscopy. Mechanical properties of joints were evaluated by tensile strength tests. Results show that copper content of the weld is increased by adopting copper side beam offset. So the population of Cu-Ti compounds is decreased and solid solution of copper is increased. Consequently, mechanical property of the joint is improved. There is just a little titanium alloy on the top of the weld melted when beam offset is up to 1 mm. And the joint is formed by brazing process according to the filling of the top fluid metal into the butt-weld. Finally, the tensile strength of the joint can reach to 300 MPa. Fracture occurs in copper alloy during tensile strength tests with plastic fracture mode.