Study on mechanical properties and microstructure of bonding interface of Ta-2.5W/TC11 explosive-welded composite pipes

Ta-2.5W/TC11爆炸焊接复合管结合界面力学性能及微观组织形貌研究

¹ School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
² Jianshe Industry Group (Yunnan) Co., Ltd., Chongqing 400054, China

Received: 22 May 2025

Abstract

To test the feasibility of the Ta-2.5W/TC11 explosion welding process, a composite pipe with a Ta-2.5W tantalum alloy cladding and a TC11 titanium alloy base was fabricated using explosion welding. The microstructure, elemental distribution, and mechanical properties of the interface between the Ta-2.5W/TC11 explosion-welded composite pipe were systematically analyzed using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and a universal testing machine. The results showed that the interface of the composite pipe consisted of both a flat interface and a wavy interface, with a large number of molten layers. Within the molten layers, some defects such as voids and inclusions were observed. Elemental diffusion occurred on both sides of the composite pipe interface, driven by concentration gradients, and the diffusion area in the molten layer is larger than the directly bonded interface. Furthermore, mechanical property tests indicated that the axial compressive yield strength of the prepared Ta-2.5W/TC11 composite pipe reached as high as 1 040 MPa. However, in the radial flattening test, the radial compression rate was only 10.5%, and the interface shear strength was only 76 MPa. These results indicate that the Ta-2.5W/TC11 composite pipe has high strength in the axial direction, and the explosion welding process for fabricating Ta-2.5W/TC11 composite pipes is feasible, though the bonding performance of the interface still needs improvement.

摘要

为了检验Ta-2.5W/TC11复合管爆炸焊接工艺的可行性, 采用爆炸焊接工艺试制出以Ta-2.5W钽钨合金为覆层、TC11钛合金为基层的复合管。通过光学显微镜、扫描电子显微镜、能谱扫描仪以及万能试验机, 对Ta-2.5W/TC11爆炸焊接复合管结合界面的微观形貌、元素分布和力学性能进行系统分析。结果表明, 复合管界面由平直界面和微波界面组成, 且界面存在大量的熔化层, 其中熔化层中发现有空洞及夹杂物等缺陷。由于浓度梯度的作用, 复合管结合界面两侧的元素发生了扩散, 且熔化层扩散区域大于直接结合界面。此外, 力学性能试验表明, 制备的Ta-2.5W/TC11复合管的轴向压缩屈服强度高达1 040 MPa, 但在径向压扁试验中径向下压率仅为10.5%, 界面压剪强度仅为76 MPa, 这表明Ta-2.5W/TC11复合管在轴向上具有较高的强度, 爆炸焊接制备Ta-2.5W/TC11复合管工艺可行, 但在复合管界面结合性能方面仍有待提高。