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Downlthe ceramic offers thermal barrier effects and protects the metal from corrosion and oxidation while the FGM is toughened and strengthened by the metallic composition. Materials will exhibit creep and stress relaxation behavior at high temperatures. Vis-coelasticity offers a reasonable basis for the study of phenomeno-logical behavior of creep and stress relaxation. The correspon-dence principle is probably the most useful tool in viscoelasticity because the Laplace transform of the viscoelastic solution can be directly obtained from the existing elastic solution. The viscoelas-tic correspondence principle, unfortunately, does not hold, in gen-eral, for FGMs. Paulino and Ji