Creep behaviour of shock-wave-surface-treated aluminium–MWCNT nanocomposites

Abstract

This work focuses on the creep characteristics of shock-wave-surface-treated aluminium (Al) nanocomposites for aerospace and defence applications. Aluminium nanocomposites underwent surface treatment in a shock tube under free-piston set-up conditions. An indentation creep study of the shock-wave-surface-treated Al–4.9Mg alloy (AA5083) reinforced with multi-walled carbon nanotube (MWCNT) nanoparticles with varying weight fractions under two stresses – namely, 113 and 170 MPa – at different temperature ranges from 473 to 573 K. The base and nanocomposite materials were developed using a semi-solid-state casting method. The instantaneous shock material reaction was characterised by carbide formation of the developed 1.50 and 1.75 wt% nanocomposites. The obtained results of the creep study showed that the nanocomposites with 1.50 and 1.75 wt% MWCNT had better creep resistance and stress exponent values at high working temperatures compared with the base alloy material. The enhanced creep resistance was due to the increased addition of MWCNT nanoparticles into the Al–4.9Mg matrix material and nanostructured carbide formation. The attained stress exponent values indicate that the major creep mechanism in the base alloy and nanocomposite materials was grain boundary sliding.