Grain-boundary segregation in Al–10%Mg alloys at hot working temperatures

Abstract

Monte-Carlo simulations are done to determine Mg enrichment at various grain-boundaries of Al–10%Mg alloys at hot working temperatures. The interatomic potentials used in the simulations are developed using the force-matching method. The Mg segregation levels at the grain-boundaries are found to vary from 20% to 40%. The segregation enrichment differences at different grain-boundary sites are explained in terms of atomic size and local hydrostatic stress. The segregation level varies strongly with [110] tilt boundaries from low to high angle while showing minimal variation with [100] twist boundaries. Segregation levels are found to have some correlation with grain-boundary energy. The effect on grain-boundary decohesion due to Mg segregation is found to be a modest (10--35%) reduction in fracture energy compared to the fracture energy in pure Al.