Automotive Applications for MMC's Based on Short Staple Alumina Fibres 870437
Reinforcement of aluminium alloys with short staple alumina fibres results in greatly enhanced modulus, improved tensile and fatigue strength, lower coefficient of thermal expansion and superior wear resistance.
Driven by the need to build lighter weight, quieter, more fuel efficient engines, the automotive industry has recognised the potential for materials substitution offered by such a property package. As a result, the technology which has been established to selectively reinforce pistons for advanced diesel engines is now being applied to other components such as the connecting rod, piston pin, cylinder liner and various areas of the cylinder head and valve train. In the longer term, further weight savings are possible by using magnesium matrix composites, while recent advances with a powder metallurgical route may lead to wider exploitation of MMCs, particularly if extrusion processing can be developed to minimise fibre damage without sacrificing fibre alignment.
In conclusion, the prospects for MMCs are extremely bright, but the size of the commercial opportunity will depend heavily on the bearable cost premium for a particular duty. The key to success therefore lies in achieving still greater manufacturing efficiencies and in introducing novel design concepts wherever possible.