Study on correlation between mechanical properties and micro/nano-structure of Sm2Co17-type permanent magnets

Sm₂Co₁₇-type permanent magnets are extensively utilized in high-temperature applications due to their exceptional magnetic properties and thermal stability. However, their poor mechanical properties increase manufacturing costs and shorten their operational lifespan. In this work, we have investigated the intricate relationship between the mechanical properties and the micro/nano-structure within Sm₂Co₁₇-type magnets. We found that a magnet characterized by small grain size, grain boundaries enriched with a Cu-rich phase, and a fine and complete cellular nanostructure within the grains exhibit excellent flexural strength. At the micro-scale, the grain refinement effectively prevents crack propagation. Additionally, the Cu-rich phase enhances the inter-grain bonding and strengthens grain boundaries. At the nano-scale, the development of fine and uniform cellular nanostructure within the grains further amplifies the magnet's superior mechanical properties by facilitating more uniform stress distribution and enhanced resistance to deformation. These findings have the potential to guide the optimization of the mechanical properties of Sm₂Co₁₇-type magnets.