A Fundamental Approach to Fatigue Behavior of Ni-Base Superalloys - A Review

Abstract

Many researchers have defined fatigue as a process that occurs over centuries. The major categories are load control/elastic range and strain control/elasto-plastic range responses. In both cases they are defined as slip band intrusions and extrusions phenomena in the crystalline metal grains within the competing processes of strain hardening and recovery at high temperature. The imposition of temperature, corrosion and mechanical phenomena complicates the formulations in certain cases. The facts illustrated in this review contain different aspects of fatigue with particular reference to Ni-base superalloys. However the experimental instances are grouped for every possibility of fatigue at high temperature. These include high cycle fatigue, low cycle fatigue, creep fatigue, thermal fatigue, thermomechanical fatigue and corrosion fatigue. Corrosion fatigue on the other hand helps in responses to fatigue failure, where changes of surface area of metals by corrosion phenomenon are responsible for such increments of stress/strain. The influence of thermal barrier coating (TBC) on fatigue of nickel base superalloys has been examined.