Influence of dry frictional heating on acceleration disruption in a railgun with a metal armature

•A mathematical model of the contact zone heating by dry friction is formulated.•An analytical solution of the model is obtained using fractional calculus.•The criterion of no melting of the contact zone is derived.•Factors responsible for the rail/armature contact zone destruction are shown.•It is shown that only composites can provide stable armature/rail contact.