Influence of B4C on the tribological and mechanical properties of Al 7075–B4C composites

In the present investigation, the influence of B4C on the mechanical and Tribological behavior of Al 7075 composites is identified. Al 7075 particle reinforced composites were produced through casting, K2TiF6 added as the flux, to overcome the wetting problem between B4C and liquid aluminium metal. The aluminium B4C composites thus produced were subsequently subjected to T6 heat treatment. The samples of Al 7075 composites were tested for hardness, tensile, compression, flexural strengths and wear behavior. The test results showed increasing hardness of composites compared with the base alloy because of the presence of the increased ceramic phase. The wear resistance of the composites increased with increasing content of B4C particles, and the wear rate was significantly less for the composite material compared to the matrix alloy. A mechanically mixed layer containing oxygen and iron was observed on the surface, and this acted as an effective insulation layer preventing metal to metal contact. The coefficient of friction decreased with increased B4C content and reached its minimum at 10 vol% B4C.

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