Evaluation of Cu-Ti dissimilar interface characteristics for wire arc additive manufacturing process

Purpose The purpose of this research is to show the characteristics of a Cu-Ti dissimilar interface produced by a wire arc-based additive manufacturing process. The purpose of this research was to determine the viability of the Cu-Ti interface for the fabrication of functionally graded structures (FGS) using the wire arc additive manufacturing (WAAM) process. Design/methodology/approach This paper used the WAAM process with variable current vis-a-vis heat input to demonstrate multiple Ti-6Al-4V (Ti64) and C11000 dissimilar fabrications. The hardness and microstructure of the dissimilar interfaces were investigated thoroughly. The formation of Cu-Ti intermetallic at the Ti64/Cu fusion interface is been revealed by scanning electron microscopy and energy dispersive X-ray analysis, while X-ray diffraction was used to identify various Cu-Ti intermetallic phases. The effect of microstructure on interfacial sensitivity and hardness are also investigated. Findings The formation of CuTi intermetallic and the beta-phase transformation in Ti-6Al-4V are found to be heat input dependent. The Cu diffusion length increases as the heat input for Ti64 deposition increases, resulting in a greater Cu-Ti intermetallic thickness. The Cu-Ti interface properties improve when the heat input is less than approximately 250 J/mm or the deposition current is less than 90 A. The microhardness ranges from 55 to 650 HV from the Cu-side to the interface and from 650 to 350 HV from the interface to the Ti-side. Higher current increases interface hardness, which increases brittleness and makes the interface more prone to interfacial cracking. Originality/value Nonlinear components are needed for a variety of extreme engineering applications, which can be met by FGS with varying microstructure, composition and properties. FGS produced using the WAAM process is a novel concept that requires further investigation. Despite numerous studies on Ti-clad Cu, information on Cu-Ti interface characteristics is lacking. Furthermore, the suitability of the WAAM process for the development of Cu-Ti FGS is unknown. As a result, the goal of this research article is to fill these gaps by providing preliminary information on the feasibility of developing Cu-Ti FGS via the WAAM process.