Direct observation of texture memory in hydrogenation-disproportionation-desorption-recombination processed Nd-Fe-B magnets using electron backscatter diffraction

Memory of texture in hydrogenation-disproportionation-desorption-recombination (HDDR) processed NdFeB magnets was directly observed using electron backscatter diffraction (EBSD). By precise control of dynamic HDDR processing conditions, shape changes of samples were minimized by proper modifications of dimensions of samples subjected to HDDR treatment. EBSD analysis shows the preservation of texture before and after the HDDR process and biaxial texture in initial Nd₂Fe₁₄B grains after the dynamic HDDR treatment at a hydrogen pressure of 30 kPa. It is clearly demonstrated that the c-axis of initial Nd₂Fe₁₄B matches the c-axis of recombined Nd₂Fe₁₄B and it recovers after an anisotropic HDDR process.