Powder/die friction in the spark plasma sintering process: Modelling and experimental identification

The powder/die friction phenomenon is known to generate densification inhomogeneities in the spark plasma sintered sample. The measurement of a powder/solid friction coefficient at high temperature is very difficult if not impossible by classical means. Then, an experimental/simulation method of identification of the friction coefficient based on the sample displacement field is introduced. This reveals that the friction of contact type powder/wall is low and about 0.1 and the friction type powder/graphite-foil/wall is close to zero. The relative density inhomogeneities are limited to a maximum difference of 3%. (C) 2016 Elsevier Ltd. All rights reserved.