Material Science & Engineering Assignment 3 PDF

Material Science and Engineering Assignment 3 Imperfection in Solids 1. The equilibrium fraction of lattice sites that are vacant in silver (Ag) at 700 C is 2 x 10-6. Calculate the number of vacancies (per cubic meter) at 700 C. Assume a density of 10.35 g/cm3 for Ag. (10pts) 2....

Material Science and Engineering Assignment 3 Imperfection in Solids 1. The equilibrium fraction of lattice sites that are vacant in silver (Ag) at 700 C is 2 x 10-6. Calculate the number of vacancies (per cubic meter) at 700 C. Assume a density of 10.35 g/cm3 for Ag. (10pts) 2. Calculate the unit cell edge length for an 80 wt% Ag - 20 wt% Pd alloy. All of the palladium is in solid solution, the crystal structure for this alloy is FCC, and the room-temperature density of Pd is 12.02 g/cm3. (10pts) 3. Calculate the energy for vacancy formation in nickel (Ni), given that the equilibrium number of vacancies at 850 C (1123 K) is 4.7 x 1022 m-3. The atomic weight and density (at 850 C) for Ni are, respectively, 58.69 g/mol and 8.80 g/cm3.(10pts) Diffusion 1. Determine the carburizing time necessary to achieve a carbon concentration of 0.30 wt% at a position 4 mm into an iron–carbon alloy that initially contains 0.10 wt% C. The surface concentration is to be maintained at 0.90 wt% C, and the treatment is to be conducted at 1100 C. Use the diffusion data for g-Fe in Table below. (10pts) 2. A sheet of BCC iron 2-mm thick was exposed to a carburizing gas atmosphere on one side and a decarburizing atmosphere on the other side at 675C. After reaching steady state, the iron was quickly cooled to room temperature. The carbon concentrations at the two surfaces of the sheet were determined to be 0.015 and 0.0068 wt%, respectively. Compute the diffusion coefficient if the diffusion flux is 7.36 x 10-9 kg/m2-s. Hint: Use Conversion from weight percent to mass per unit volume Equation to convert the concentrations from weight percent to kilograms of carbon per cubic meter of iron. (10pts)