Fabrication and evaluation of mechanical and tribological properties of boron carbide reinforced aluminum matrix nanocomposites

In this study, fabrication and characterization of bulk Al–B4C nanocomposites were investigated. B4C nanoparticles were mixed with pure Al powder by ball milling to produce Al–B4C powder. Al–B4C powders containing different amounts of B4C (5, 10 and 15 wt.%) were subsequently hot pressed to produce bulk nanocomposite samples. Consolidated samples were characterized by hardness, compression and wear tests. Results showed that the sample with 15 wt.% B4C had the optimum properties. This sample had a value of 164 HV which is significantly higher than 33 HV for pure Al. Also, ultimate compressive strength of the sample was measured to be 485 MPa which is much higher than that for pure Al (130 MPa). The wear resistance of the nanocomposites increased significantly by increasing the B4C content. Dominant wear mechanisms for Al–B4C nanocomposites were determined to be formation of mechanical mixed layer on the surface of samples.

Research highlights
► Al–B4C nanocomposites were fabricated by mechanical alloying and hot pressing.
► Mechanical and triboligical properties of Al–B4C nanocomposites were investigated.
► Ultimate compressive strength of sample with 15 wt.% B4C was measured to be 485 MPa.
► Formation of MML increased the wear resistance of Al–B4C nanocomposites.