Improving the Fatigue Property of Metallic Glass by Tailoring the Microstructure to Suppress Shear Band Formation

Metallic glass (MG) usually exhibits poor fatigue property, limiting its application as structural materials. Shear bands play a key role in fatigue crack initiation and propagation of MG. In this work, to enhance the fatigue property of MG, we proposed and verified a new strategy of suppressing the shear band initiation and then impeding the fatigue crack formation through relaxing the microstructure, in contrast to the previous one of proliferating shear bands through toughening MG. Moreover, simple quasi-static tests including uniaxial tension, compression and notch tension, are employed as feedback to estimate the best microstructure after relaxing and then the optimal fatigue property of MG. It is found that if the relaxed samples exhibit higher compressive elastic limit and tensile strength, but only slightly decreased notch toughness than the as-cast samples, the fatigue property of relaxed samples can be obviously enhanced. The present strategy provides a promising way for enhancing the fatigue endurance property of MGs without the requirement of intrinsically large plasticity, which may thus be beneficial for the structural application of most MGs with high glass forming ability.