First-principles tensile tests of tilt and twist grain boundaries in Al

Abstract

In order to clarify the basic mechanical behavior of grain boundaries (GBs) in Al under tensile stresses, the first-principles tensile tests of coincidence tilt and twist GBs in Al have been performed by using the projector augmented wave (PAW) method based on the density-functional theory (DFT) within the generalized gradient approximation (GGA). For the {221} = 9 tilt and {∑} = 5 twist GBs in Al, we have obtained ideal strength and stressstrain curves, and analyzed bond-breaking behavior. Results for the = 9 tilt GB are consistent with previous results using the local density approximation (LDA). The = 5 twist GB reveals complex behavior of deformation and failure, different from tilt GBs. In both the interfaces, reconstructed interfacial bonds reveal high strength, inducing large deformation in the GB regions before the failure, due to the covalent bonding nature of Al. © 2011 The Japan Institute of Metals.