a) List three mechanisms for the toughening of ceramic materials and their composites, with a description of each. b) The supersonic wind tunnels at the Aerodynamics Laboratory at Cambridge University are powered by a bank of 20 large cylindrical pressure vessels. Each time the tunnels are used, the vessels are slowly charged by compressors and then quickly discharged through the tunnel. Given the following material data for a pressure vessel steel and Al alloy, determine the maximum allowable crack length that can be tolerated to avoid unstable fracture (Hint: Plot σpv vs. crack length a). Estimate the crack as a semi-circular surface flaw orientated along the axis of the vessel with a surface depth twice its max depth. σy (MPa) Kc (MPa√ m) Steel 1000 170 Aluminum 400 25 c) Which material would give the better overall defect tolerance at a stress level appropriate to each (ignore fatigue issues)? d) How could you go about designing the material such that it could be readily determined if a vessel, which has been in service for some time, becomes unsafe prior to the vessel exploding?

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a Ceramic materials and their composites can be toughened via three different mechanisms Reduction of Grain Size When the grain size of ceramic materi... View the full answer