CNTs reinforced Al-based composites produced via modified flake powder metallurgy

The bimodal Al–Mg alloy structure reinforced with carbon nanotubes was evaluated after the composites production through a modified flake metallurgy technique followed by hot extrusion. The obtained bimodal microstructure of the matrix allowed to identify the microstructural mechanisms, leading to high strength, uniform elongation and strain hardening ability of the produced composites. The effect of the reinforcing phases percentages on the dislocations mechanisms evolution was evaluated through stress relaxation tests, leading to the underlying of the effect of reinforcing phases on the modification of the interphase influence zone. The results revealed that the deformation mechanism for unreinforced Al–Mg materials was forest dislocation cutting, whereas for CNT reinforcing Al–Mg composite was grain boundary and interface mediated straining. In fact, for Al–Mg/CNT composite, a task allocation occurred during the deformation process, namely at the early deformation stage by forest dislocation cutting and afterward at later deformation stage by dislocation/grain boundary/interface interaction.