Spark plasma sintering of in situ and ex situ iron-based amorphous matrix composites

Reinforcement of amorphous matrices with the nanocrystalline phases is widely recognized as an important approach for enhancing the general plasticity of structural amorphous materials. In this paper, spark plasma sintering of highly dense iron-based amorphous alloy and its tungsten particulate reinforced composites is reported. The partial devitrification of amorphous matrix into nanocrystalline Fe23(C, B)6 during spark plasma sintering led to the formation of in situ amorphous matrix composites. Furthermore, ex situ amorphous matrix composites reinforced with micron-size tungsten particles were successfully fabricated. The evolution of phase, microstructure, and relative density with spark plasma sintering parameters is discussed. Special emphasis is placed on understanding the densification behavior of the amorphous and composite amorphous/crystalline powder during spark plasma sintering from the variation of punch displacement with time during sintering.