Question 5 of 20 View Policies !!! Current Attempt in Progress At approximately what temperature (in Kelvin) would a specimen of an alloy have to be carburized for 1.9 h to produce the same diffusion result as at 810C for 15 h? Assume that values for Do and Qd are 3.8 106 m/s and 144 kJ/mol, respectively. T = i K Question 6 of 20 < > View Policies Current Attempt in Progress A diffusion couple of two metals, A and B, was fashioned as shown: Diffusion of A atoms A A-B alloy B -/1 !!! Diffusion of B atoms After a 650 hour heat treatment at 1080C the concentration of A is 3.0 wt% at the 3.1 mm position within Metal B. At what temperature (in Kelvin) must the diffusion couple need to be heated to produce this same concentration at a 2.3 mm position after 650 h? The preexponential and activation energy values for the diffusion of A in B are 2.8 10-5 m/s and 263 kJ/mol, respectively. i K Question 8 of 20 < View Policies -/1 !!! ... Current Attempt in Progress For a steel alloy it has been determined that a carburizing heat treatment of 16 h duration at 718C will raise the carbon concentration to 0.37 wt% at a point 2.5 mm from the surface. Estimate the time necessary to achieve the same concentration at a 8.2 mm position for an identical steel and at a carburizing temperature of 1120C. Assume that Do is 4.4 x 104 m/s and Q is 109 kJ/mol. i h