Enhancing the mechanical properties of ultrasonic spot welded Cu/Ti joints using a magnetron-sputtered Al interlayer
Materials Characterization, cilt.240, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 240
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.matchar.2026.117017
- Dergi Adı: Materials Characterization
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Cu/Ti joint, Magnetron-sputtered Al interlayer, Mechanical properties, Ultrasonic spot welding
- Karadeniz Teknik Üniversitesi Adresli: Evet
Özet
The focus of this study is on ultrasonic spot welding (USW) of dissimilar Cu and Ti assisted by a magnetron-sputtered Al interlayer, which is adopted to compensate for the limited interfacial diffusion, thereby enhancing the load-bearing capacity of the joint. Welding parameter effects on interfacial microstructure and mechanical properties are systematically analyzed through orthogonal and single-variable experiments. Results demonstrate that the Al interlayer alters the reaction route: the original Cu-Ti pathway is replaced by an Al-Cu system that produces CuAl2 intermetallic compound (IMC) and an Al-Ti system exhibiting stronger interdiffusion. Under optimal conditions, the USWed Cu/Al/Ti joint achieves a tensile shear load of 2808.57 N, which is approximately 65% higher than that of the Cu/Ti joint, while fracture displacement increases by about 44%, with the fracture mode transitioning from interfacial brittle fracture to ductile fracture of the Cu base metal. EBSD analysis reveals that the Al interlayer promotes dynamic recrystallization on the Cu side by increasing heat input, raising high-angle grain boundary and twin boundary fractions, and forming a fine-grained zone. It also optimizes crystallographic orientation and plasticity on the Ti side. Excessive welding time (1.2 s) reduces the effective bonded area and degrades performance. This work demonstrates an efficient interlayer strategy for Cu/Ti USW and provides insights into interfacial reaction control.