Additive Manufacturing of Topologically Engineered Double Half-Heusler High-Entropy Alloy with Enhanced Thermoelectric Properties

Abstract

The present work attempts to design topologically engineered double-half Heusler high entropy alloys for thermoelectric (TE) applications using the additive manufacturing (AM, direct ink writing) technique. Using the AM, materials with enhanced surface area/volume ratio are designed, which significantly enhances the thermal gradient (≈170 K) across the ends. The increase in the thermal gradient and high surface area/volume ratio reduces thermal transport without compromising the electronic conduction. Moreover, the power factor for the additively manufactured structure shows an increase of ≈38.2% compared to that of the conventionally manufactured structure. In addition to the improved TE properties, the porous additively manufactured architecture shows improved mechanical properties (three times higher ultimate compressive strength). A detailed computational validation supports the experimental observations (electronic as well as thermal behavior). The simulation demonstrates that the additively manufactured porous TE legs offer enhanced TE properties due to sluggish thermal transport without alteration of the Seebeck coefficient. Thus, the present study comprehensively elucidates the role of AM in improving TE performance by optimizing the porosity and topology of the TE leg.