Effects of Structure on Creep of Ti-53.4mol%Al Intermetallics

Abstract

ABSTRACTConstant stress compression creep behavior at elevated temperature was investigated on Ti-53.4mol%Al polycrystalline intermetallics of gamma single phase in different grain morphologies: coarse columnar grains, fine recrystallized grains and equiaxed grains. The shape of creep curves depended on the applied stress: normal primary transient followed by steady creep was found at higher stresses, but at lower stresses steep acceleration was observed after taking minimum creep rates. This behavior was common to all the grain morphology. The creep rate itself was not greatly different among the three types of structure, and the stress exponent of about 4 and the apparent activation energy of about 340kJ/mol at 0.3 true strain were common to all three types. The shape and size of grains do not affect the essential creep features of this material.