Elastic-plastic analysis of deformation induced by thermal stress in eutectic composites: II. thermal Expansion

Abstract

In part I a theory was developed to analyze the deformation produced in eutectic composites by temperature changes. Experimental determinations of the coefficient of expansion are used here to test the predictions of that theory. Measurements of length versus temperature in the absence of external stresses were made for Al-Al₃Ni, Al-CuAl₂, and Sb-Cu₂Sb eutectic composites, and for monolithic 6061 Al. Hysteresis loops in the graph of composite coefficient of expansion vs temperature are seen when the expansion coefficients of the phases are different and plastic deformation occurs. The nature of the hysteresis is shown to depend upon heating and cooling rates, prior history and the relative values of the matrix and reinforcement expansion coefficients. The theory correctly predicts these qualitative effects. In Al-Al₃Ni the available component data justify a quantitative comparison of calculated and experimentally determined coefficient of expansion-temperature curves. The values compare well, further verifying the analytical approach.