Nanoindentation, Scratch, and Corrosion Studies of Aluminum Composites Reinforced with Submicron B4C Particles

The relationship between point defects and mechanical properties has not been fully understood yet from a theoretical perspective. This study systematically investigated how the Stone–Wales (SW) defect, the single vacancy (SV), and the double vacancy (DV) affect the mechanical properties of graphene/aluminum composites. The interfacial bonding energies containing the SW and DV defects were about twice that of the pristine graphene. Surprisingly, the interfacial bonding energy of the composites with single vacancy was almost four times that of without defect in graphene. These results indicate that point defects enhance the interfacial bonding strength significantly and thus improve the mechanical properties of graphene/aluminum composites, especially the SV defect. The differential charge density elucidates that the formation of strong Al–C covalent bonds at the defects is the most fundamental reason for improving the mechanical properties of graphene/aluminum composites. The theoretical research results show the defective graphene as the reinforcing phase is more promising to be used in the metal matrix composites, which will provide a novel design guideline for graphene reinforced metal matrix composites. Furthermore, the sp3-hybridized C dangling bonds increase the chemical activity of the SV graphene, making it possible for the SV graphene/aluminum composites to be used in the catalysis field.

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Effect of Boron Carbide Addition on Wear Resistance of Aluminum Matrix Composites Fabricated by Stir Casting and Hot Rolling Processes

Metals ◽

10.3390/met11060989 ◽

2021 ◽

Vol 11 (6) ◽

pp. 989

Author(s):

Donghyun Lee ◽

Junghwan Kim ◽

Sang-Kwan Lee ◽

Yangdo Kim ◽

Sang-Bok Lee ◽

...

Keyword(s):

Wear Resistance ◽

Boron Carbide ◽

Hot Rolling ◽

Rolling Direction ◽

Aluminum Matrix ◽

Stir Casting ◽

Aluminum Matrix Composites ◽

Wear Depth ◽

Wear Properties ◽

B4c Particles

In this study, to evaluate the effect of boron carbide (B4C) addition on the wear performance of aluminum (Al), Al6061 and 5, 10, and 20 vol.% B4C/Al6061 composites were manufactured using the stir casting and hot rolling processes. B4C particles were randomly dispersed during the stir casting process; then, B4C particles were arranged in the rolling direction using a hot rolling process to further improve the B4C dispersion and wear resistance of the composites. Furthermore, a continuous interfacial layer between B4C and the Al6061 matrix was generated by diffusion of titanium (Ti) and chromium (Cr) atoms contained in the Al6061 alloy. Wear depth and width of the composites decreased with increasing B4C content. Furthermore, with B4C addition, coefficient of friction (COF) improved as compared with that of Al6061. The results indicate that interface-controlled, well-aligned B4C particles in the friction direction can effectively increase the wear properties of Al alloys and improve their hardness.

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