June 23, 2026Open Access
Tuning intermetallic growth and flexural performance in gallium-based amalgams via Sn/In alloying and solidifying at controlled temperature
Key Points
- To examine how alloying gallium-based amalgams with Sn/In and solidification temperature affects their mechanical and microstructural properties.
- Mixed copper particles with gallium, GaIn, GaSn, and GaInSn alloys for solidification at room temperature or 100 °C.
- Conducted four-point flexural testing to assess strength after solidification.
- Analyzed fracture surfaces to determine microstructural characteristics.
- Ga and GaSn reached a flexural strength of ~7 MPa after solidification at 100 °C.
- GaIn and GaInSn exhibited weakening due to more ductile features disrupting the CuGa₂ framework.
- The combination of composition and solidification temperature was crucial for balancing strength and ductility.
Abstract
Gallium-based amalgams and preforms offer promising pathways for room-temperature bonding and low-temperature structural fabrication, yet their mechanical performance is constrained by brittle failure after interdiffusion-based solidification. This study investigates the mechanical and microstructural evolution of pastes formed by mixing copper particles with gallium (Ga), eutectic gallium-indium (GaIn), eutectic gallium-tin (GaSn), and eutectic gallium-indium-tin alloys (GaInSn), subjected to solidification at either room temperature or 100 °C. Four-point flexural testing showed that Ga and GaSn both strengthened after 100 °C solidification, reaching similar strength levels (~ 7 MPa), whereas GaIn and GaInSn weakened. Fracture surfaces showed plate-like intermetallic cleavage in Ga and GaSn, consistent with a rigid CuGa₂ framework. GaIn and GaInSn displayed more ductile features from dispersed In or InSn regions that disrupt CuGa₂ continuity. Overall, composition and solidification temperature control the balance between rigid intermetallic reinforcement and softer secondary phases. GaSn provides the most practical combination of strength, consistency, and cost for these low-temperature metal systems.