MS&E 410/610 Problem set #3 1) You are given a bar of pure aluminum with a grain size of 1 mm. Tensile testing reveals that the yield stress of this material is very low. Describe two reasonable processes by which you could increase the strength of this bar. (Note: “reasonable” here means a process that one could imagine using in an industrial process. Melting and recasting the bar with a different composition, or other time- or energy-intensive processes, would not be reasonable.) Make sure to describe both the processes and the changes to the microstructure that should result. Please also include a description of any scaling laws that help you make your case. Short answers should be sufficient. 2) Dendritic growth due to constitutional supercooling is very common in solidification of alloys. Use the following three assumptions to construct a logical argument (do not attempt a mathematical derivation) for why constitutional supercooling occurs: • Assuming that there is no convection ahead of the solidification front, the
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Tensile strength, constitutional supercooling, lowest biaxial stiffness, fcc metal films