Diffusion, Fick’s first and second laws of diffusion and diffusion mechanisms, interface, fully coherent, semi coherent and incoherent interfaces, interfacial energy and strain energy and coherency loss, solidification, nucleation and growth, solidification of alloys and eutectics, diffusional transformation: nucleation and growth, TTT diagram, spinodal transformation, diffusion less transformation and strengthening mechanism, applications of phase transformations