Microstructure Evolution and Mechanical Properties of Melt Spun Skutterudite-based Thermoelectric Materials

Area of Science:

• Materials Science
• Solid State Physics

Background:

• Melt spinning is a common technique for producing high-performance skutterudite thermoelectric materials.
• Understanding microstructure formation and its impact on mechanical properties is crucial for optimizing these materials.

Purpose of the Study:

• To investigate the microstructure evolution and mechanical properties of La-Fe-Co-Sb skutterudite alloys.
• To compare the effects of melt-spinning and long-term annealing followed by sintering.

Main Methods:

• Fabrication of skutterudite alloys using melt-spinning and long-term annealing followed by sintering.
• Analysis of microstructure evolution during processing.

Main Results:

• Skutterudite phase nucleated as submicron dendrites during melt spinning.
• Spinodal decomposition formed nanoscale La-rich and La-poor phases at 473 K.
• Melt-spun samples exhibited a 70% increase in three-point bending strength (195 MPa) compared to annealed samples.

Conclusions:

• The combination of micron-scale grains, submicron dendrites, and nanoscale spinodal decomposition enhances thermoelectric performance and mechanical strength.
• Melt spinning offers a promising route for developing robust skutterudite thermoelectric materials.