Effects of Composition Changes on Strength, Bend Ductility, Toughness, and Flex-Bending Fatigue of Iron-Based Metallic Glass Ribbons

摘要

Vickers microhardness, nanohardness, tension tests, notch and fatigue precrack toughness tests, and controlled monotonic and cyclic strain experiments via bending over mandrels of different diameter have been performed on two different chemistries of Fe-based (Fe-Si-B) metallic glass ribbons. The tensile strengths of Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 were 2000 ± 100 MPa and 1640 ± 35 MPa for Fe_(78)Si_9B_(13), which is consistent with the microhardness trends. High notch toughness (e.g., 89 ± 0.9 MPam~(1/2) - Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9; 94.5 ± 5.5 MPam~(1/2) - Fe_(78)Si_9B_(13)) and fatigue precracked toughness of 76 MPam1/2 for the Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 and 80 MPam~(1/2)' for the Fe_(78)Si_9B_(13) were obtained. Flex-bending cyclic fatigue tests revealed a fatigue limit of 385 MPa for Fe_(78)Si_9B_(13) ribbons, whereas the more brittle behavior of the Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 ribbons prevented the generation of flex-bending fatigue data. These results are discussed in the light of recent work on metallic glass systems.