Ultrasonic Assisted Room Temperature Welding of Liquid Gallium Indium Alloy Brazing Material and Its Solidification Behavior at the Cu-Cu Interface

Considerable the gallium-based alloys low melting point coupled with easy to synthesize intermetallic compounds with diverse metallic elements, employing liquid gallium-based alloys as the soldering medium and leveraging ultrasonic as assistance are effective to construct pure copper joints under atmosphere condition. The investigation delves into the characterization of the reaction products, interface microstructure, elemental distribution patterns, and evolution of shear strength within the welds. Furthermore, the pivotal role of ultrasonic waves and constituent element diffusion mechanisms during the solidification phase is elucidated. Thus, the initial one-day occurred during solidification showed the 2.6 MPa shear strength but with the time increased to four and a half days, the shear strength raised to 8.4 MPa at room temperature. Thereinto, the results indicate the weld seam has achieved metallurgical connection. This innovative welding technique operates at room temperature provides significant guidance for designing a novel perspective low-temperature joining for applications. It is not only augments the repertoire of material connection methodologies but also presents a viable joining strategy for sensitive elevated temperature materials. Therefore, such process possesses substantial practical significance and promises avenues for future applications.