Optimized microstructure and enhanced multifunctional properties of Sn-25Bi solder alloys reinforced with exfoliated Ti3C2Tx MXene nanosheets

Purpose This study aims to examine the impact of Ti3C2Tx MXenes incorporation on the structural, mechanical, thermal, electrical and wettability characteristics of the Sn-25Bi binary solder alloy. Design/methodology/approach Sn-25Bi-mTi3C2Tx nanocomposite solder alloys (m = 0, 0.2, 0.4, 0.6 and 0.8 Wt.%) were developed by blending Sn and Bi powders with Ti3C2Tx MXene nanosheets. The mixtures were compacted into disc-shaped pellets using a 12 mm diameter steel die and a manual hydraulic press with a 5-tonne jack, which ensured uniform densification and adequate green strength. Findings The incorporation of 0.4 Wt. % of Ti3C2Tx significantly enhances Vickers microhardness (Hv) and elastic modulus (Y), achieving values of 40.5 MPa and 0.67 GPa, respectively, which corresponds to about a 97% increase compared to the Ti3C2Tx-free alloy. Differential scanning calorimetry (DSC) indicated a decreased melting temperature of 194.99°C and a constricted mushy zone of ΔT = 11.29°C, implying enhanced thermal stability and consistent phase transition behavior at 0.4 Wt.%. Moreover, the solder’s wettability was improved, demonstrated by a minimum contact angle of 20.7° and a maximum spreading area of 0.773 cm2 at the identical composition. Electrical characterization demonstrated a substantial reduction in electrical resistivity (ρ) by approximately 35% and a notable increase in free electron concentration (N) and Fermi velocity (Vf). However, excessive MXene loading beyond 0.4 Wt.% resulted in agglomeration-induced performance degradation across all investigated properties. Research limitations/implications The results are confined to the Sn-25Bi/Ti3C2Tx formulations examined. Further microstructural examination is necessary to enhance comprehension of the distribution of MXene nanosheets and their interactions with the solder matrix. Further investigations ought to concentrate on the enduring thermal and electrical dependability of the fortified alloys under pertinent operational settings to clarify the mechanisms responsible for property improvements and assess the practical soldering utility of the optimized composition. Originality/value This study explores the development of MXene-reinforced Sn-25Bi solder alloys with optimized microstructure and enhanced multifunctional properties.