Evolution of the internal friction in Sic particle reinforced 8090 Al-Li metal matrix composite

The present Study has been undertaken to investigate the mechanism of therm al stress relief at the range of temperatures below room temperature for th e metal matrix composite Al-Li 8090/SiC. For this aim the experimental tech nique of internal friction has been used which has been showed up very effe ctive. Several thermal cycles from 453 K to 100 K were used in order to mea sure the internal friction as well as the elastic modulus of the material c oncluding that thermal stresses are relaxed by microplastic deformation aro und the reinforcements. It has been also related the variation in the elast ic modulus with the different levels of precipitation.