FATIGUE LIFE PREDICTIONS FOR NOTCH GEOMETRIES IN PARTICLE-REINFORCED METAL-MATRIX COMPOSITES

The potential use of particle reinforced metal matrix composites (MMCs ) for demanding structural applications highlights the need for an eff ective method to predict the fatigue performance of notched components . The present paper evaluates the 'critical strain' technique and its suitability with respect to particle reinforced MMC alloys. Strain con trolled fatigue data generated on the aluminium alloy 2124 reinforced by two different fractions of 2-3 mu m SiC particle are used to predic t the lives of a 'pseudocomponent' representative of engineering situa tions. It is demonstrated that both alloys are essentially cyclically stable compared with monotonic work hardening curves and, where availa ble, date from tension and torsion modes superimpose on a Von Mises ef fective stress-strain criterion. The implications of the fatigue life analysis are discussed. MST/4033.