Unformatted text preview: t the initial particle radius is negligibly small. Assume particle growth is governed by Be diffusion and can be modeled as r 2 = Dt , where r is the particle radius, D is the diffusivity, and t is the aging time. (b) During this initial aging process, the precipitates maintain coherency with the crystalline host material and thus can be treated as a weak obstacle. Calculate the obstacle shear strength as a function of aging time. Assume that the entirety of the obstacle strengthening in this regime is due to a coherency “misfit” strain (hydrostatic) of ε misfit = 0.01 € (c) Upon reaching the equilibrium volume fraction of precipitate, the particles are found to coarsen with continued aging. During this stage, the size of the precipitate increases accordin...
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This document was uploaded on 02/10/2014.
 Fall '14

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