Nanomechanical Responses of an Intermetallic Compound Layer in Transient Liquid Phase Bonding Using Indium

Low-temperature transient liquid phase bonding (TLPB) can be achieved using indium, and the joints thus formed can withstand high temperatures. Since the joints that are formed with TLPB entirely consist of intermetallic compounds (IMCs), this study investigates the phase evolution and mechanical properties of IMCs that are obtained from isothermal reactions between In and commonly used substrate metals, Cu, Ag and Au. Using nanoindentation, the relationships between the yield strain, work hardening exponent and strain rate sensitivity of In-bearing and other frequently observed IMC phases were compared. Notably, the strain-induced precipitation of Ag3In occurred in the indent of Ag9In4.