THERMAL GROOVING IN 3 PERCENT SILICON-IRON

The grain-boundary grooving technique has been used to determine the transport mechanism and the grain-boundary energies in randomly oriented and in textured 3% silicon-iron strips. The matter transport mechanism was found to be mainly volume diffusion, and the calculated diffusion coefficient was: Dm=0.15 exp [ -(47 500±6300)/R T] The average energy of incoherent large-angle grain-boundaries is shown to be 0.37 times the surface energy at 1150° C and 0.30 times at 1250° C: the difference is tentatively explained in terms of oxygen absorption and the contribution of evaporation condensation to the transport mechanism. Results from textured specimens suggest that all incoherent large-angle boundaries have approximately the same energy per unit surface. Lower energies are typical of low-angle boundaries and of coincident-site boundaries containing a sub-boundary consisting of a few dislocations. © 1969 Chapman and Hall.