Material Selection for Ramjet Engines

Selection of materials for the ramjet engine requires not only considering conventional problems for designing high-temperature materials but also the problem of oxidation and weight. A high degree of reliability combined with a minimum amount of maintenance presents contradictory but necessary design requirements. Combustor accessories such as flameholders require materials having high-temperature strength combined with low oxidation properties. A flameholder must be capable of serving its function without appreciable erosion since burnout could affect the flame-holding stability. Long-range ramjets (cruisers) impose evaluating very critical time-temperature problems. In fact, physical and mechanical properties of materials (modulus of elasticity) vary downward with increasing temperature. The choice of material then is not trivial.