ANALYSIS OF KINETICS OF DIFFUSION-INDUCED RECRYSTALLIZATION IN FE PHASE OF CU FE/CU DIFFUSION COUPLES/

Combining the columnar-geometry and boundary-diffusion model by Li and Hillert with the energy balance model by Kajihara and Gust, a new kin etic equation has been obtained to describe the growth rate of the all oyed region due to diffusion induced recrystallization (DIR) in a solu tion phase of binary systems. The equation has been utilized to analyz e quantitatively the kinetics of DIR in the Fe(Cu) system observed by the present authors using Cu/(Fe-4.8mass%)/Cu diffusion couples. The n otation Fe(Cu) means that Cu atoms diffuse into a pure Fe or binary Fe -Cu phase. The observations indicate that the thickness I of the DIR r egion formed in the Fe phase from each interface increases with increa sing annealing time t according to the relationship l=1.58 x 10(-6)(t/ t(0))(0.29) at 1 323 K. Here, l and t are measured in m and s, respect ively, and t(0) is unit time, 1 s. Using the mobility M as the fitting parameter of the kinetic equation, we have obtained the value of M=8. 64 x 10(-13) m(4)/J s and the relationship 1=1.08 x 10(-6)(t/t(0))(0.3 3) on the basis of the observations. Through the analysis, it is concl uded that l increases in proportion to root t for DIR in a pure metal whereas I increases proportionately with (3) root t for DIR in a solut ion phase even with a low solute concentration.