An undergraduate course introducing diffusion mechanisms under different circumtances in crystalline materials, diffusion Fick's laws, crystal interfaces, diffusional and non-diffusional phase transformations in metals. References: (1) D.A. Porter and K.E. Easterling; Phase Transformations in Metals and Alloys, Chapman & Hall, 2nd ed. 1992. (2) R. Reedhill & R. Abbaschian; Physical Metallurgy Principles, PWS Publishing, 3rd ed., 1994.