Principal Scientific Officer, Springfields Nuclear Power Development Laboratories, United Kingdom Atomic Energy Authority (Northern Division), Lancashire,
Pages: 17 Published: Jan 1988
A study has been made of the low-cycle fatigue behavior of austenitic stainless steels and a magnesium alloy over a wide range of temperature. The effects of microstructural variation on fatigue life of these materials which exhibit different crystal structures and deformation modes have been studied by thermo-mechanically treating material prior to testing and by inducing grain boundary creep cavitation during elevated temperature unbalanced creep-fatigue cycles. For balanced cycles microstructural changes result in moderate variations in fatigue life, despite changes in failure mode from trans- to intercrystalline. On the other hand, the introduction of discrete creep-type grain boundary cavities during elevated temperature unbalanced creep-fatigue cycles can cause an order of magnitude reduction in fatigue life. The effects observed in these two materials are rationalized in terms of current theories of fatigue failure and serve as a basis of assessing other materials.
fatigue, creep, stainless steels, magnesium alloy, grain size precipitates, crack initiation, crack propagation, transgranular, intergranular
Paper ID: STP24517S