Atomistic Study of the Thermal Stress due to Twin Boundaries

Abstract

There is compelling evidence for the critical role of twin boundaries in imparting the extraordinary combination of strength and ductility to nanotwinned metals. This paper presents a study of the thermal expansion of coherent twin boundaries (CTBs) at finite temperature by way of atomistic simulations. The simulations reveal that for all twin boundary spacings d, the thermal expansion induced stress varies as 1/d. This surprisingly longrange effect is attributed to the inhomogeneity in the thermal expansion coefficient due to the interfacial regions.