Estimation of stored energy in deformed metals from EBSD data sets

A number of methods for estimating the stored energy of deformation from EBSD data have been examined.The methods are illustrated here using samples of AA1100 deformed to strains of εvM=2.4 and εvM=4.0 using the accumulative roll bonding process.A qualitative method,based on pattern contrast,reveals some aspects of local differences in stored energy in the deformed samples.Quantitative methods where the stored energy is estimated through the use of the Read-Shockley equation have also been examined.A special mean misorientation angle is developed to take account of nonlinearity of the Read-Shockley equation.Two approaches have been considered.One is based on subgrain reconstruction and the other is based on misorientation angles taken directly from an orientation map.Calculations show that the subgrain method is particularly sensitive to orientation noise in the data and care must be taken when using this method.