The purpose of the research to be performed on this RIA award is to provide information on fundamental mechanisms that manifest during the brittle-to-ductile transition (BDT) process using a novel experimental technique. The issues to be addressed are: (1) whether BDT is controlled by crack tip dislocation nucleation or dislocation mobility; (2) what are the critical crack tip dislocation configurations that result in BDT; (3) what is the strain rate sensitivity of the BDT; and (4) what are the effects of impurities on the BDT.
