Abstract
Electron-microscopic observation has been made of the subgrains formed in cold-worked aluminium with the following results : (1) The prominent slip bands (S-bands) have the character of subboundaries, forming subgrains bounded by them, (2) the S-bands also form the subgrain in conjunction with deformation bands, (3) a further refinement of the subgrain, to the size smaller than one micron, occurs mainly by formation of small kink bands (K-bands), and (4) the final size of the subgrain is independent of the grain size before working.
