The densification mechanism of amorphous Fe 48 Cr 15 Mo 14 Y 2 C 15 B 6 alloy powder during isochronal spark plasma sintering was analyzed to determine the innate function of high heating rates. Densification ensued and concluded at gradually lower temperatures while attaining higher maximum rates with increasing heating rates in the first stage. The shrinkage behavior analyzed under the theoretical framework of viscous flow revealed a steady reduction in the activation energy leading to a resultant enhancement of densification rate in the initial stage.

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A quantitative understanding of the role of ultrasonic treatment (UST) process variables on microstructure and mechanical properties is critical for the development of process maps for manufacturing metal matrix composites (MMCs). This article presents a novel mathematical framework to delineate the functional correlations among ultrasonication time, grain refinement, and hardening in SiC nanoparticle-reinforced Al matrix composites. UST generates microbubbles and deagglomerates SiC to increase heterogeneous nucleation sites synergistically. The increase in volumetric nucleation density due to SiC addition exhibits slow exponential kinetics with varying ultrasonication time. An outstanding grain refinement efficiency of 62.8% is achieved upon ultrasonication for 90 s. The contributions to an increase in the hardness due to grain refinement and SiC dispersion are isolated to develop correlations between ultrasonication time and hardening. Hardening increases exponentially with treatment time due to the reduction of interparticle distance from sonication-induced SiC dispersion. These fundamental mathematical correlations constitute a significant advancement toward the development of ultrasonic process maps and MMC manufacturing technology.