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Metallurgical Engineering Foundry Metallurgy Difficulty: Medium

The theoretical density of an fcc metal with atomic radius and atomic weight of 0.144 nm and 197 gm.mol -1 respectively, is approximately (in kg.m -3 ) The critical internal crack length (in mm) in a steel having K lc of 45 Mpa √m to support a Mode-I-stress of 400 Mpa is Soldering clearance is given for brass is Transport mechanisms that do not contribute to densification during sintering are: P. Surface diffusion Q. Bulk diffusion R. Bulk diffusion S. Evaporation-condensation T. Viscous flow The diffusion couple shown below is made from two A-B alloys. The initial compositions of the two alloys are indicated in the diagram. The centreline is at x = 0. The couple is held at an elevated temperature for 40 hours. Diffusivity; D = 3 × 10 -11 m -2 s -1 . Assume the diffusion couple to be infinitely long. Which of the parameters give the composition profile in the following form? $$C\left( {x,t} \right) + {c_1} + {c_2}\,erf\left( {\frac{1}{{2\sqrt {Dt} }}} \right)$$