AFM, SEM AND TEM study of damage mechanisms in cyclically strained mar-M247 at room temperature and high temperatures

Cylindrical specimens of γ́ precipitate strengthened superalloy MAR-M247 were cyclically strained under total strain control conditions using a symmetrical push–pull cycle at 23 °C, 700 °C and 800 °C in air. The fatigue hardening/softening curves and low cycle fatigue life curves are presented. Special attention is paid to the effect of temperature on plastic strain localisation and fatigue crack initiation at 23 °C, 700 °C and 800 °C. Plastic...