EFFECT OF SPECIMEN THICKNESS ON MECHANICAL-PROPERTIES OF POLYCRYSTALLINE AGGREGATES WITH VARIOUS GRAIN SIZES

The flow stress of polycrystalline Al, Cu, Cu-13 at% Al and Fe have been investigated as a function of the grain size and the specimen thickness. The flow stress decreases with decreasing specimen thickness when the ratio of specimen thickness (t) to grain size (d) is smaller than a critical value. The critical value of t/d increases with decreasing both grain size and stacking fault energy. Based on the experimental results the radius of affected zone, in which individual grains strongly interact with each other caused by a deformed grain, is estimated using a simple model. The result shows that the long-range interaction among individual grains expands into a wide region across the first nearest-neighbor grains. © 1979.