Problem 6
A disk of Ti-40 at.% V is bonded to a disk of pure Ti with an inert marker placed at the plane of bonding. The diffusion couple is then annealed at 1300°C in an inert atmosphere for 1 hour. After the diffusion couple experiment, the inert markers are identified at a distance of 13.2 μm from the Matano plane (xo). The vanadium concentration at the marker plane is 19.5 at.% and the intrinsic diffusion coefficient, Dv and Dri, at the marker composition are 3.9x10^-cm/sec and 2.0x10^-cm/sec, respectively. Assume a constant molar volume V of 9.5 cm^3/gmole.
(a) Draw a schematic diagram of the concentration profiles (Cv and CT vs. x) and identify the areas that represent the cumulative intrinsic fluxes of V and Ti.
(b) Evaluate the intrinsic flux, Jv and Jri, at t=1 hour.
(c) Evaluate the interdiffusion flux J at the marker plane at t=1 hour.
(d) Determine the position and velocity of the marker plane expected at t=6 hours.
Note on conversion of flux units:
atf cm^-1 moles Flux = (sec/100) * V cm^2/sec