Analysis of large dislocation populations in deformed metals

The microstructural evolution is followed in pure aluminium and nickel cold-rolled over a large strain range. A number of dislocation configurations are characterized and classified and it is found that dislocation rotation boundaries are the dominant feature which subdivide the grains on a finer and finer scale as the strain is increased. These configurations of dislocation boundaries are analyzed on the basis of the LEDS hypothesis for dislocation structures and agreement is found. The strengthening effect of dislocation boundaries is discussed and equations are suggested for the relationship between now stress and microstructural parameters.