Hardening of a metallic glass during cyclic loading in the elastic range

Although fatigue failure is well documented in metallic glasses, the mechanism responsible for damage accumulation during cyclic loading below the yield point remains elusive. This letter describes a high-resolution nanomechanical study of an Fe-based bulk metallic glass subjected to cyclic loading in the nominal elastic range. An increase in the yield load was observed with an increasing number of subyield loading cycles, providing a clean documentation of kinematic irreversibility in very small volumes of material that experience no shear bands either prior to or during cyclic loading.