Influence of ZrB2 Particles on Dry Sliding Wear Behaviour of AA7075/ZrB2 In-Situ Composites

Abstract

AA7075/ZrB2 Aluminium Matrix Composites (AMCs) were successfully fabricated using the in-situ fabrication method. The inorganic salts (K2ZrF6 and KBF4) reacted with molten aluminium at 900 °C and formed ZrB2 inside the melt itself. AMC castings were obtained in different volume fractions (0, 3, 6 and 9%) of ZrB2. The dry sliding wear behaviour of AA7075/ZrB2 in-situ AMCs was evaluated using pin-on-disc wear apparatus. The wear experiments were executed as per Design of Experiments (DoE). The effect of wear parameters such as sliding velocity, sliding distance, content of ZrB2 and normal load on wear rate was analyzed. It was evident that ZrB2 particles influenced the wear resistance of fabricated AMCs. The worn surfaces revealed an increase in number of cracks when sliding velocity, sliding distance and normal load increased. The worn surface of AA7075/ZrB2 AMCs was observed using Field Emission Scanning Electron Microscopy (FESEM). The wear rate was decreased and the corresponding wear resistance was increased when the volume fraction of ZrB2 particles increased in the fabricated AMCs.