Answer Happy

Question-4. (10 points). Determine the non-steady-state diffusion time in hours) necessary to achieve a zinc (Zn) concentration of 0.04 wt% at a position of 2.5 mm into a copper (Cu)-Zn alloy that initially contains 0.0005 wt% Zn. The surface concentration is to be maintained at 0.85 wt% Zn under a temperature of 950 °C. The diffusion preexponential and activation energy are 2.4 X10 5 m/s and 1.89 *10J/mol. R = 8.3145 J/mol-K. 0 Z erf(z) zerf(z) z erf(z) o 0.55 0.5633 1.3 0.9340 0.025 0.0282 0.60 0.6039 1.4 0.9523 0.05 0.0564 0.65 0.6420 1.5 0.9661 0.10 0.1125 0.70 0.6778 1.6 0.9763 0.15 0.1680 0.75 0.7112 1.7 0.9838 0.20 0.2227 0.80 0.7421 1.8 0.9891 0.25 0.2763 0.85 0.7707 1.9 0.9928 0.30 0.3286 0.90 0.7970 2.0 0.9953 0.35 0.3794 0.95 0.8209 2.2 0.9981 0.40 0.4284 1.0 0.8427 2.4 0.9993 0.45 0.4755 1.1 0.8802 2.6 0.9998 0.50 0.5205 1.2 0.9103 2.8 0.9999