Effect of quenching media on properties of aluminium-alumina metal matrix composite

Abstract

Particle reinforced aluminium matrix composites are frequently used in various automotive and aerospace applications involving critical functions like piston rings, wing mid and inner cover etc. Here the composites are frequently subjected to extreme conditions involving large temperature differentials in a short period of time like in pistons facing an average temperature of 300 0C or in aeroplane wings facing cryogenic temperatures at high altitudes. Such conditions can deteriorate the particle matrix interface resulting in a decreased ability to resist matrix deformation or strengthen the matrix through dislocation generation due to thermal misfit between matrix and reinforcement. Hence, this phenomena has been investigated in the course of this work by quenching aluminium alumina micro and nano composites in different quenchants and studying the effects on mechanical properties as well as the microstructure. Increase in hardness was likely due to dislocation generation as was realized from the greater increase for higher vol. fration reinforcement composites, while post quench softening was likely due to decohesion and cracking of matrix and particles.