Low cycle fatigue (LCF) properties were investigated on Fe-20%Cr ferritic stainless steel processed by equal channel angular pressing (ECAP). The Fe-20%Cr alloy bullets were processed for four pass through ECAP Routes-A,Bc and C. The ECAPed samples were cyclically deformed at constant plastic strain amplitude ε_<pl> of 5x10^<-4> at room temperature in air. All the samples showed the cyclic softening which continued until fatigue fracture. At initial stage of the fatigue test, 4C sample exhibited the lowest stress amplitude of 400MPa, while 4A and 4Bc samples showed higher stress amplitudes of 580MPa and 560MPa respectively. Fatigue lives of 4A, 4Bc and 4C samples were 13,000, 22,000 and 16,000 cycles, respectively. The difference in the initial stress amplitudes can be attributed to microstructure: dominant grain boundaries of the 4C sample revealing the low stress amplitude were low-angle grain boundaries while the 4A and 4Bc samples contained large amount of high-angle grain boundaries and fine grains of iglu diameter. The long fatigue life of the 4Bc sample can result from the equi-axed fine-grained structure which can inhibit crack growth towards various directions, in comparison with lamellar microstructure formed in the 4A sample.
