Influence of Armature/Rail Structure Coordination on the Evolution of Rail Deposition Layer

During the launch of the railgun, the interface of the armature/rail (A/R) will undergo severe melting and wear. The molten armature material will further solidify and deposit on the surface of the rail to form an aluminum deposition layer, which will change the original contact state and affect the subsequent armature launch performance. The evolution of the deposition layer under flat rails and D-shaped rails was experimentally studied. The study found that the deposition layer presents a changing trend of thickness on both sides and thin in the middle. With the increases in the number of experiments, the thickness of the deposition layer gradually accumulates, however, in the end, the thickness of the deposition layer tends to stabilize. Experiments have found that the horizontal distribution of the D-shaped rail deposition layer is more uniform than that of the flat rail, and the increase rate of the thickness of the deposition layer is lower than that of the flat rail. Based on the analysis of the A/R contact resistance and current density distribution, we have given an explanation for the difference in the thickness distribution of the deposition layer. In addition, the thickness of the deposition layer tends to be stable under the two rail conditions because the bond strength of the deposition layer and the rail decreases after repeated launch, and the tensile stress increases, which leads to the peeling off of the deposition layer.