Abstract
The internal structure of rolled zinc is believed to be as follows: the hexagonal base lies nearly parallel to the plan of rollig, i.e. fibreaxis coincides with the hexaganal axis and lies in the plane containing the direction of rolling and normal to the plane of rolling, but the axis being scattered about 20° to the direction of rolling and also to opposite direction. This was true in the specimen rolled in spring and summer and the angle decreases with the rise of the temperature of rolling. Even in the specimen rolled in summer, some crystallites have their hexagonal bases in the direction perpendicular to the plane of rolling exist. But these crystallites disappear after several days and majorities of crystallites become nearly parallel to the plane of rolling. This is because the direction of crystal growth is perpendicular to the hexagonal axis and this fact was also proved from the measurement of Young’s modulus, namely, immediately after rollig, it is 7.71×10−11 dyne/cm2 and after 4 days, 8.05×10−11 dyne/cm2. If the specimen was rolled in winter, the crystallites have their hexagonal base in the direction parallel and perpendicular to that of rolling and both lying parallel to the normal of the plane of rolling predominate. The relation between these two sorts of crystallites nearly coincides with that of mechanical twin. Therefore, we can conclude that in cold state deformation of zinc is accompanied by the formations of mechanical twins, and the slip parallel to the hexagonal base is not so significant.
Above results are true for specimens both rolled parallel and perpendicular to the axes of columnar crystal grains. Zinc will much easily be worked if the direction of rolling coincides with the axes of long columnar grains.
