Karpovych Olena, Karpovych Ivan, Fedosov Oleksii, Zhumar Denys, Karakash Yevhen, Rimar Miroslav, Kizek Jan, Fedak Marcel
Department of Rocket and Space and Innovative Technologies, Oles Honchar Dnipro National University, Nauky Ave., 72, 49005 Dnipro, Ukraine.
Department of Technology of Aircraft Manufacturing, Oles Honchar Dnipro National University, Nauky Ave., 72, 49005 Dnipro, Ukraine.
Materials (Basel). 2025 Jul 31;18(15):3596. doi: 10.3390/ma18153596.
The object of this study is welded joints of AISI 321 and Ti-6Al-4V, obtained by diffusion welding on developed conical surfaces. The problem of creating bimetallic joints of AISI 321 and Ti-6Al-4V with developed conical contact surfaces, using diffusion welding through an intermediate Electrolytic Tough Pitch Copper (Cu-ETP) copper layer, was solved. The joints were studied using micro-X-ray spectral analysis, microstructural analysis, and mechanical tests. High mutual diffusion of copper and titanium, along with increased concentrations of Cr and V in copper, was detected. The shear strength of the obtained welded joints is 250 MPa and 235 MPa at 30 min and 15 min, respectively, which is higher than the copper layer's strength (180 MPa). The obtained results are explained by the dislocation diffusion mechanism in the volume of grains and beyond, due to thermal deformations during welding. Under operating conditions of internal pressure and cryogenic temperatures, the strength of the connection is ensured by the entire two-layer structure, and tightness is ensured by a vacuum-tight diffusion connection. The obtained strength of the connection (250 MPa) is sufficient under the specified operating conditions. Analysis of existing solutions in the literature review indicates that industrial application of technology for manufacturing bimetallic adapters from AISI 321 stainless steel and Ti-6Al-4V titanium alloy is limited to butt joints with small geometric dimensions. Studies of the transition zone structure and diffusion processes in bimetallic joints with developed conical contact surfaces enabled determination of factors affecting joint structure and diffusion coefficients. The obtained bimetallic adapters, made of Ti-6Al-4V titanium alloy and AISI 321 stainless steel, can be used to connect titanium high-pressure vessels with stainless steel pipelines.
本研究的对象是通过在已开发的锥形表面上进行扩散焊接获得的AISI 321和Ti-6Al-4V焊接接头。解决了使用中间电解韧铜（Cu-ETP）铜层通过扩散焊接创建具有已开发锥形接触表面的AISI 321和Ti-6Al-4V双金属接头的问题。使用微X射线光谱分析、微观结构分析和力学测试对接头进行了研究。检测到铜和钛的高相互扩散，以及铜中Cr和V浓度的增加。所获得的焊接接头在30分钟和15分钟时的剪切强度分别为250 MPa和235 MPa，高于铜层的强度（180 MPa）。所获得的结果可以通过焊接过程中热变形导致的晶粒体积内外的位错扩散机制来解释。在内压和低温条件下运行时，连接强度由整个两层结构保证，密封性由真空密封扩散连接保证。在规定的运行条件下，所获得的连接强度（250 MPa）是足够的。文献综述中对现有解决方案的分析表明，由AISI 321不锈钢和Ti-6Al-4V钛合金制造双金属适配器的技术的工业应用仅限于几何尺寸较小的对接接头。对具有已开发锥形接触表面的双金属接头的过渡区结构和扩散过程的研究使得能够确定影响接头结构和扩散系数的因素。所获得的由Ti-6Al-4V钛合金和AISI 321不锈钢制成的双金属适配器可用于连接钛高压容器和不锈钢管道。
