What is low cycle fatigue?

According to the low cycle fatigue, the nominal maximum stress values are less than the ultimate tensile stress limit.

Low cycle fatigue is failure under a stress reversal after less than 1000 cycles and generally occurs in metals where strains are very high, where stresses are in the plastic region

High cycle fatigue is failure under a stress reversal after more than 1000 cycles and generally occurs in metals where strains are low, caused by defects, and growth, where stresses are in the elastic region