Behavior of a Unidirectional Metal-Matrix Composite Under Thermomechanical Loading

Abstract

The thermoelastoplastic behavior of a unidirectional metal matrix composite (SiC/Al) under thermomechanical loading was studied with a micromechanical model based on the average field theory. The silicon carbide fiber is considered elastic and temperature independent whereas the matrix is thermoviscoplastic and fitted into a series of power law strain hardening models. The thermoelastoplastic analysis of the composite was carried out by introducing the concept of secant properties of the matrix. Analytical predictions were compared with experimental results. Under longitudinal tensile loading the predicted stress-strain curves were in good agreement with experimental curves at three temperatures (24, 288, and 399°C). Under transverse tensile loading the secant properties of the matrix and the average stresses in the matrix and fiber (at room temperature) were obtained as a function of applied stress. The predicted stress-strain curves under transverse loading were in satisfactory agreement with experimental ones at temperatures up to 399°C. Longitudinal and transverse thermal strains as a function of temperature were also predicted and compared favorably with experimental measurements.