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The use of Aluminum Metal Matrix Composites (MMC's) is becoming a viable solution to help meet the new regulations of the medium to heavy-duty truck markets. The objective of this paper is to present both analytical and dynamometer data that demonstrate the damage tolerance of a selectively reinforced Aluminum MMC brake drum. In particular, dissimilar coefficients of thermal expansion (CTEs) between the MMC and Aluminum portion of the drum results in favorable compressive stresses in the Aluminum. This state of stress facilitates the slowing of crack growth for flaws whose depth reaches the boundary between MMC and Aluminum. This paper will present an analytical study utilizing finite-element models to predict stress levels in a drum subject to thermal and mechanical loading. Examination of the stress-fields for braking events at room temperature and elevated temperature provides evidence of the aforementioned compressive stresses in the Aluminum portion of the drum.