Understanding the influence of processing routes on grain boundary structure and crystallographic texture is essential for optimizing the magnetic performance of nanocrystalline Nd–Fe–B magnets. In this study, a five-parameter crystallographic analysis was employed to systematically investigate the influence of spark plasma sintering and hot deformation sintering on the grain boundary plane distribution and crystallographic texture of nanocrystalline Nd–Fe–B magnets. Its reveals that the hot deformation process confers marked advantages in promoting strong c-axis texture and tailoring grain boundary configurations. In hot deformed samples, 001-oriented grains predominate, with the c-axis strongly aligned along the pressing direction, resulting in a significantly enhanced texture strength compared to spark plasma sintering samples. The grain boundary plane distribution in hot deformed samples exhibits a pronounced preference for low-index planes such as (001) and (110), with a peak intensity reaching 9.9 multiples of random distribution. In contrast, spark plasma sintering samples display a more randomized boundary plane distribution. Further, the five-parameter analysis indicates that the hot deformation processing promotes stronger preferential grain boundary plane alignments within specific misorientation ranges. Indeed, hot deformed samples demonstrate superior magnetic properties, with a remanence of 12.5 kG and a maximum energy product of 35.7 MGOe. Collectively, these findings clarify the intrinsic distinctions in microstructural evolution between the spark plasma sintering and hot deformation processes and underscore the utility of the five-parameter analysis in linking the processing pathways to microstructure and performance. This work provides a theoretical foundation for the grain boundary engineering and the optimization of processing routes toward high-performance rare earth magnets.
Li et al. (Sat,) studied this question.