Effects of Tailoring Zn Additions on the Microstructural Evolution and Electrical Properties in GaInSnZnx High-Entropy Alloys

One major hindrance that now-available low-melting-point alloys (LMPAs) for extensive applications is the limitation of cost and electroconductivity. GaInSnZnx high-entropy alloys (HEAs) feature tunable solid-liquid phase transitions and are synthesized via induction melting, whose microstructural evolution and electrical properties are investigated by changing the composition. A sweepthrough composition space indicates these alloys are a mixed multiphase microstructure of low-melting-point near-liquid Ga-based solid solution and other relatively high-melting-point phases throughout, which is considered as the origin of stiffness transition of alloys. Varying molar amounts of Zn from 1 to 3, the volume fraction of Zn-based solid-solution phase gradually increases and its morphology changes from rod shape to island-like structure. The electroconductivity keeps a continuous increment from 4.68 to 6.35 MS m(-1), and in consideration of cost, these alloys have remarkable superiority over many LMPAs. The virgation between the electrical experimental and theoretical values computed using the volume model and multiphase alloy model is thoroughly elaborated, in which the presence of grain boundaries plays a dominant role. The present study provides a new design mentality to fabricate stiffness-adjustable alloys with low cost and high conductivity and enriches alloy species in LMPA-HEAs.