Al-TiB{sub}2, an alternative material for high temperature and wear resistant transport application

摘要

The transport industry is continuously seeking new light materials to comply with the low fuel consumption policies and enhanced technical requirements. The use of Metal Matrix Composites (MMCs) is seen as a feasible alternative to substitute several grey cast iron steel and non reinforced aluminium alloys components as they present outstanding specific properties, high wear resistance as well as low Coefficient of Thermal Expansion (CTE). The results obtained during a research project that studied the actual possibilities, processing optimisation and mechanical properties of an aluminium matrix composite reinforced with in-situ produced TiB{sub}2 ceramic particles are presented. Railway and automotive components were produced by Gravity Casting, High Pressure Die Casting (HPDC) and a variant of the Sand Costing process called "Multipouring" and the melt behaviour and obtained mechanical properties were analysed and evaluated. The material presented a remarkable improvement of properties when compared with the corresponding non-reinforced alloys. Furthermore, the presence of the TiB{sub}2 particles conferred a thixotropic nature to the melt whose positive effects during the filing step could also be noticed during the production of prototypes.