Formation of prismatic dislocation loops during unloading in nanoindentation

Abstract

The formation of prismatic dislocation loops during nanoindentation of bcc iron is simulated with discrete dislocation plasticity. Interestingly, it is not the loading phase, but the unloading phase of the test which is found to be crucial for prismatic loop formation when indenting a (001) crystal surface. In this case, prismatic loops do not form during loading, but develop as the indenter is removed, in contrast to (111) indentation where prismatic loops are nucleated almost immediately upon loading.