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An isentropic, one-dimensional model is used to analyse the dynamics of dilute two-phase (feed powder particles plus the carrier gas) flow during the cold-spray process. While the physical foundation of the model is quite straightforward, the solution for the model can be obtained only numerically. The results obtained show that there is a particle-velocity-dependent, carrier-gas-invariant optimal value of the relative gas/particle Mach number that maximizes the drag force acting on feed powder particles and, hence, maximizes the acceleration of the particles. Furthermore, it is found that if the cold-spray nozzle is designed in such a way that at each axial location the acceleration of the particles is maximized, a significant increase in the average velocity of the particles at the nozzle exit can be obtained. For the optimum design of the nozzle, helium as the carrier gas is found to give rise to a substantially higher exit velocity of the particles than air. All these findings are in good agreement with experimental observations.

Failure of the ceramic gun‐barrel lining during single‐shot and burst firing events has been studied by combining a finite‐element method based thermo‐mechanical analysis with a structural reliability analysis. An initial distribution of residual stresses in the lined barrel, as introduced during shrink‐fitting of the steel jacket over the ceramic lining, is taken into account. Forced‐convection boundary conditions at the inner surface of the barrel are determined by carrying out an internal‐ballistic analysis, followed by compressible boundary‐layer modeling of the heat transfer coefficient. The results obtained reveal that due to thermal expansion of the steel jacket during single‐shot and burst ballistic events, tensile axial stresses develop in the ceramic lining near the barrel ends. These stresses are sufficiently high, particularly in the case of burst firing, that they can induce formation of circumferential cracks and, in turn, failure of the lining. Using the Weibull structural reliability analysis, the failure probability for the lining has been computed as 0.0025 and 0.0121 for the single‐round and the 10‐round firing modes, respectively. Optimization of the main design, materials and processing parameters in order to minimize the failure probability for the lining is also discussed.