The Effect of Multi-walled Carbon Nanotubes, as the Reinforcement Phase, on the Hardness and Bending Strength of Aluminum Alloy 7075

In the present investigation, to fabricate Nano-composites made of wrought aluminum alloy 7075 and multi-walled carbon nanotubes, carbon nanotubes and the alloy powders were initially dispersed in ethanol using an ultrasonic shaker to form a primary mixture. The milled powder mixture was converted into the final specimens by Spark-Plasma Sintering. To achieve a uniform distribution of carbon nanotubes in the matrix alloy, ethanol or stearic acid can be used as a Processing Control Agent (PCA). For each of the seven specimens, a series of tests were performed to study the effects of the reinforcement phase on the base alloy. As shown, the reinforced specimens were harder compared to the pure Al7075 and the sample reinforced with 1wt% of multi-walled carbon nanotubes has both the highest hardness and flexural strength among all the specimens. Additionally, when the weight fraction reached 2%, there was a noticeable drop in the mechanical properties. This novel alloy produced by powder metalurgy can be very helpul for industrial application where the increase in strength and hardness is deireable.