The present study explores an experimental investigation of dissimilar welding of austenitic stainless steel (AISI 316) with nitinol (NiTi) plates by inserting copper (Cu) as an interlayer using a fiber laser system. The presence of copper influences controlling the formation of brittle intermetallic compounds forming compounds of copper with iron, titanium, and nickel. The weldments are examined to understand the physical and mechanical properties of the joints. A micrograph study of welded joints shows a crack-free surface and reveals the nature of solidification in the weld zone. The analysis of pores in the weldment indicates the presence of 1.89%, 2.26%, and 6.32% of pores in the weld zone area of three different weldment samples, 1, 2, and 3, respectively, and the obtained porosity percentage was quite satisfactory. The insertion of copper helps in attaining the welded joints bearing a tensile strength of 219.74 MPa. The failure of the welded joint shows a mixed nature of fracture. This study suggests that the presence of an interlayer during joining of dissimilar materials provides stable, crack-free, and less brittle joints as compared to joining of dissimilar materials without an interlayer.

中文翻译：

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使用光纤激光技术对 AISI 316/Cu/SMA 异种激光焊接接头的物理和机械特性进行表征

本研究通过使用光纤激光系统插入铜 (Cu) 作为夹层，对奥氏体不锈钢 (AISI 316) 与镍钛诺 (NiTi) 板的异种焊接进行了实验研究。铜的存在影响控制脆性金属间化合物的形成，形成铜与铁、钛和镍的化合物。检查焊件以了解接头的物理和机械性能。焊接接头的显微照片研究表明表面无裂纹，并揭示了焊接区凝固的性质。焊件气孔分析表明，1、2、3三种不同焊件试样的焊缝区分别存在1.89%、2.26%和6.32%的气孔，得到的气孔率比较令人满意. 铜的插入有助于获得抗拉强度为 219.74 MPa 的焊接接头。焊接接头的失效表现出断裂的混合性质。该研究表明，与没有夹层的异种材料连接相比，在异种材料连接过程中夹层的存在提供了稳定、无裂纹和不易碎的接头。