Powder Technology for Material Processing

Particle-level correlations that guide product structure–property outcomes in advanced processing and manufacturing unit operations for material processes are well documented. The influences of bulk granular and powder property effects on structure–property functions, however, remain elusive. The bulk effects depend on the ensemble of particle packing and require a multi-scale evaluation (characterization), which includes the nano/micro-scale (particle level), meso-scale (stress networking and packing fluctuations), and the macro-scale (bulk behavior). Granular and powder bed characterization for the purpose of predicting suitability for forming is traditionally limited to static particle-level characterization. To enable the characterization of meso-scale linkages between the nano/micro-scale and granular/powder bed bulk properties for structure–property function, it is suggested that granular/powder process understanding should be an integration of three areas: (1) static particle-level characterization (i.e., size, shape, surface area, chemical composition, etc.), (2) comminution and dynamic (transformative) granular and powder characterization (e.g., the bulk solid rheology), and (3) final part forming. The aforementioned static characteristics are necessary but not sufficient in light of insights gained from selected dynamic bulk granular/powder bed characterization techniques.