✍ Scribed by Lin, Yijian ;Wu, Xingfang ;Ke, Jun ;Cahn, R. W.
No coin nor oath required. For personal study only.
An annealing study was performed on cold-rolled IC-218 alloy (an advanced form of nickel aluminide) with a reduction of 607. During isochronal annealing for 10 min, a hardness maximum was found at 475 C; this was due to reordering, as confirmed by DSC analysis. When the annealing temperature was raised above 675 C, recovery softening began and became more pronounced with increase of temperature, indicating a kinetic competition between strain-age hardening by reordering and recovery softening by thermally activated dislocation mobility. Recrystallization started readily above 775 C, with strongly preferential nucleation at shear bands. However, growth of the new grains was very slow and the growth rate progressively decreased; many grains stopped growing at a size of 5 to 10 mm. This led to peculiar kinetics, characterized by a very sluggish progress of the fraction recrystallized, X V , during the stage of 207 X V 507. If the Avrami equation X V 1 À exp ÀBt k was formally used to describe the process in this stage, an extremely small value of the Avrami exponent k 0X24, resulted. An Arrhenius plot for X V 407 yielded an apparent activation energy of % 230 kJamol, which was found to be equal to that of dislocation recovery.
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## Abstract The microstructure of partially annealed and additionally rolled 1050 aluminum alloy of commercial purity was monitored using FEG/EBSD in situ heating experiments in order to understand the preferential growth of Cube‐oriented grains. A fast reorganization of the deformation sub‐structu