solutionstotest12002 - Solutions to Test 1 MatSc 503 -...

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Solutions to Test 1 MatSc 503 - Kinetics of Materials Processes Test date: February 25, 2002 1. A 1-mm-thick sheet of steel at 750 ˚ C is subjected to conditions that maintain the carbon content at zero on one surface and at 3 at% carbon on the other surface. At 750 ˚ C the carbon contents of ferrite and austenite which are in equilibrium with each other are, respectively, 0.09 and 2.7at%. The diffusion coefficients of carbon in ferrite and austenite at 750 ˚ C are 5.5 × 10 -11 and 1.1 × 10 -12 m 2 /s, respectively. (a) (10 points) Schematically draw the concentration profile of carbon. At steady state: 1mm h c c 0.0 0.09at% 2.7at% 3.0at% (b) (10 points) Determine the position of the ferrite-austenite interface at steady state. At steady state, x c D x c D = γ α or h h × = × 1 7 . 2 0 . 3 10 1 . 1 0 09 . 0 10 5 . 5 12 11 Solve for the interface position h at steady state, we have mm 9375 . 0 16 15 = = h 2. Describe the TYPE of solutions that you will employ to describe the concentration profiles, or the TYPE of mathematical methods that you will use to obtain the profiles, for the following non-steady state diffusion problems: (Assuming a diffusion coefficient of 10 - 10 cm 2 /s for the diffusing species and the solid is a plate of 1cm thickness) a. (7 points) Diffusion of a thin layer of material initially deposited on one of the surfaces of the plate into the solid for 100 s. cm
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This note was uploaded on 01/19/2010 for the course MAT SCI 503 taught by Professor Chen during the Spring '02 term at Pennsylvania State University, University Park.

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solutionstotest12002 - Solutions to Test 1 MatSc 503 -...

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