Production and properties of aluminum-based composites modified with carbon nanotubes

Simultaneous Improvement of the Electric Conductive and Mechanical Properties of Nanostructured Aluminum Alloy

“…5, alongside the dimple rate for each alloy. The curve reveals that the 1SS0.05C had the best results of ultimate tensile strength, toughness, and strain, out of the tested alloys, due to it being combined with the improved mechanical properties resulting from the stainless steel powder and small additions of CNT that, according to the literature, ensure greater homogeneity, consequently reducing the appearance of agglomerates and the accumulation of stress 10,30 . The 0.05C alloy presented lower results than the other alloys, due to the agglomeration of nanotubes and the low density of the CNT that make them rise to the surface of the melting metal, as shown in Fig.…”

“…The 0.05C alloy presented lower results than the other alloys, due to the agglomeration of nanotubes and the low density of the CNT that make them rise to the surface of the melting metal, as shown in Fig. 1b 8,17,30 . CNT clusters produced an accumulation of punctual stresses, generating areas of failure and reducing the mechanical properties 30,34 .…”

“…1. It was noted that part of the mixture disperses in the liquid metal, however, it is expected that the excess mixture will agglomerate at the bottom of the crucible, due to the excess nanostructured powder having a higher density than liquid aluminum 30 . This behavior resulted in a little amount of the mixture of metallic powder and nanotubes being dispersed in the molten metal, but almost all the elements alloys were at the bottom of the crucible, reducing the reinforcement effect and deteriorating the properties of the alloy.…”

“…This decantation could occur due to the limit of solubility of the alloy elements, combined with the low temperature and the melting time 31 . For the 1SS0.05C alloy (1 wt.% SS-0.05 wt.% CNT), the reinforcement tends to disperse in the matrix when the casting is performed, with a tendency to remain dispersed in the mold, generating the best reinforcement mechanism with an excellent performance 30 . The alloys obtained were microstructurally characterized using SEM with EDS; the electric conductivity was measured both electrically and mechanically through the microhardness test and the tensile strength test.…”

“…It revealed the effect of the chemical treatment nanotubes and their capacity to be attached to the SS powder, effectively connecting the alloy elements of the SS inside the aluminum matrix, maintaning their reinforcement effect 10,30 . With higher quantities of SS and nanotubes, the reinforcement is compromised, the properties decreasing when compared to the 1SS0.05C sample, but still already above the Al EC 30 . High quantifies of SS particles powder could not be meltied in the aluminum casting, due to low temperature and short time.…”