Usinage orthogonal en phase quasi pâteuse des composites métalliques

Influence de la fraction volumique de grosses particules

Machining in semi-liquid phase of reinforced and unreinforced metal aluminum matrix composites: influence of large particles volume fraction

¹ Ingénieur diplomé de l'ETS, option Génie mécanique
² Professeur, Ecole de technologie supérieure (ETS), Université du Québec, Montréal, Canada

Abstract

Machining in semi-liquid phase of metal matrix composite aluminum based is discussed in function of the volume fraction of reinforcing large particles of silicon carbide (SiC) with a size of 120 µm. Machining those materials has been done at temperatures ranking from 600 to 350°C with classical tools in tungsten carbide (WC).

Three stage has been found out involving the cutting force according the machining temperature of the workspiece. Also a optimum machining temperature has been found in this study. This temperature set at the end of the first stage when the cutting force is low and just before the eutectic liquid is produced in the shear zone of the chip. This eutectic liquid appears before the eutectic temperature of th workpiece predicting by the classical phase diagram. The energy produced in the shear zone by cutting action explains that some metal liquid is produced below the classical eutectic temperature. A phenomenogical description of the cutting action descride the relationship between the main cutting force and the cutting parameters. Also the study shows that the main cutting force decreases with the increase of the machining temperature and the increasing of the volume fraction of particles in MMCp.