The yield strength of off-stoichiometric Ni3A1 with and without boron

In this paper compression tests have established that the addition of 0.3 at% boron does not significantly affect the contribution of the grain boundaries to the yield strength of Al-rich (26 at% Al) Ni3Al. In contrast, the boundary contribution is reduced by 42% when the same amount of boron is added to Ni-rich (24 at%) Ni3Al. In this paper these results are interpreted within the context of the structure and chemistry of the grain boundaries and, in particular, in terms of the transmission of slip through either an ordered or a constitutionally disordered grain boundary. Such boundaries have been recently observed by Baker, Schulson, Michael and Pennycock