Influence of hot extrusion on strain hardening behaviour of graphene platelets dispersed aluminium composites

Experimental work on the determination of strain hardening behaviour of Graphene Nano Platelets (GNPs) dispersed aluminium composites carried out during cold upsetting. The present work aimed to predict the effect of hot extrusion and GNPs content on strain hardening behaviour of aluminium composites. By varying the weight percentage of GNPs reinforcement from 0 to 2 wt %, aluminium composites prepared with powder metallurgy and hot extrusion technique. After each stage of deformation, each non-extruded and extruded GNP dispersed aluminium composites subjected to incremental compressive loading. The stress in axial and hoop direction, hydrostatic stress, instantaneous strain hardening exponent, and strength coefficient calculated for extruded and non-extruded GNPs dispersed aluminium composites. Found that tri-axial stresses, instantaneous strain hardening exponent, and strength coefficient have shown tremendous variation in their values for different weight percentage addition of GNPs and extrusion process. Further identified that extruded aluminium composites consisting of 1.5 wt % GNPs have a significant effect on influencing both strain hardening exponent and strength coefficient. •Strain hardening behaviour of Graphene Nano Platelets (GNPs) dispersed aluminium composites prepared by powder metallurgy and hot extrusion are determined during cold upsetting.•The axial stress, hoop stress, and hydrostatic stress values of extruded aluminium composites consisting of 1.5 wt. % GNPs show increment of 100% compared to similarly processed pure aluminium matrix and other GNPs dispersed aluminium composites.•The value of strain hardening index and strength coefficient rapidly reaches a peak value at lower strain and decreases immediately, then maintains a fluctuating and steady value at a higher strain rate.