Making High Thermoelectric and Superior Mechanical Performance Nb_0.88Hf_0.12FeSb Half-Heusler via Additive...

Area of Science:

• Materials Science
• Energy Harvesting
• Additive Manufacturing

Background:

• Thermoelectric generators offer potential for waste heat energy harvesting.
• Current fabrication methods face challenges in material utilization and processing complexity.

Purpose of the Study:

• To report a novel 3D printing process for half-Heusler thermoelectric materials using laser powder bed fusion (LPBF).
• To investigate the impact of LPBF processing on the thermoelectric properties and mechanical performance of half-Heusler materials.

Main Methods:

• Utilized laser powder bed fusion (LPBF) to fabricate the half-Heusler (Nb0.88Hf0.12FeSb) thermoelectric material.
• Characterized the microstructure, thermal conductivity, thermoelectric figure of merit (ZT), and mechanical properties of the LPBF-fabricated material.

Main Results:

• LPBF introduced intra- and inter-granular defects that significantly reduced thermal conductivity by scattering phonons.
• Achieved a high figure of merit (ZT) of approximately 1.2 at 923 K.
• Demonstrated a single-leg maximum efficiency of approximately 3.3% at a temperature difference (ΔT) of 371 K.
• Observed hafnium oxide nanoparticles mitigating crack propagation, ensuring mechanical integrity.

Conclusions:

• LPBF is a viable and advanced technique for producing high-performance, customizable half-Heusler thermoelectric materials.
• The process enables efficient energy harvesting from waste heat, paving the way for industrial applications.
• This approach holds potential for a new era of efficient thermoelectric devices.