The Mechanical and Thermoelectric Properties of Bi2Te3-Based Alloy Prepared by Constrained Hot Compression Technique

Abstract

This study proposes a constrained hot compression-molding (CHCM) technique for preparing Bi2Te3-based alloys. This method overcomes the problem of easy cleavage and destruction for the zone-melted Bi2Te3-based alloy, which is beneficial to improve the material utilization rate and thermoelectric devices yield in the commercial manufacturing process. The stress field distribution inside the CHCM specimen is explored via finite element analysis. The compressive strength of the CHCM sample is above 44 MPa, which is about 38% higher than that of the zone melting (ZM) material. Meanwhile, the CHCM sample shows a much lower electrical conductivity and thermal conductivity, but a higher Seebeck coefficient than that of the ZM sample, which is mainly due to the increase of the line defect concentration induced by the CHCM process. Finally, a maximum thermoelectric figure of merit (ZT) value of 0.6 was achieved for CHCM sample.