Influence of autofrettage on metal matrix composite reinforced gun barrels

Abstract

Advanced materials are considered as candidates for the replacement of traditional gun barrel steel with the hope that weapons as durable as steel but at a fraction of the weight will be developed. Through an analytical model that simulates the effects of autofrettage on a cylindrical gun barrel, the resultant compressive residual stresses are quantified, and different materials examined as to their possible resistance to fracture under repeated internal pressure loads. This study investigates a traditional low-alloy gun steel, a high temperature SiC/titanium-alloy metal matrix composite , as well as various hybrid combinations of these materials, for their ability to develop the necessary residual stress and inelastic strain states necessary for durability. It is discovered that a hybrid composite comprised of low-alloy gun steel on the inner region of the gun barrel and circumferentially wound SiC/Ti–24Al–11Nb on the outer region can still exhibit the same compressive residual stress (and corresponding inelastic strains) seen in homogeneous steel barrels, but with a weight savings of up to 37%, while maintaining the original barrel dimensions.