The solid particle erosion behavior of Al18B4O33 whisker-reinforced AC4C al alloy matrix composites

Steady-state solid particle erosion of squeeze-cast AC4C Al alloy and 19.5 vol.% Al 18 B 4 O 33 whisker/AC4C Al composites was investigated at room temperature. Experiments were performed with angular silica sand having four velocities (55 m s −1 , 140 m s −1 , 198 m s −1 and 243 m s −1 ) and at impact angle in the range 15° to 90°. The eroded surface and subsurface were observed using scanning electron and optical microscopy. The results indicated that erosion characteristics of the composites was affected by the particle velocity and impact angle. Steady-state rate was found to increase with the addition of whisker to the matrix alloy at high particle velocities or upon increasing impact angle. High erosion rate in the whisker reinforced composites can be attributed to reduced ductility. In addition to plastic deformation, flaking, gouging and microcutting, for the composites, fragmentation and dislodgement of Al 18 B 4 O 33 whisker occurred with impact of particles. At low particle velocity and shallow impact angle, the whisker at the surface can act as protective reinforcement to resist the microcutting and microploughing action. The erosion resistance for the Al 18 B 4 O 33 /AC4C Al composites was improved as a result of whisker addition.