β Scribed by S.V. Pan; Yu.V. Milman; A.A. Malyshenko
No coin nor oath required. For personal study only.
As a result of examination of the temperature dependences of the mechanical behaviour of iron-based metal-metalloid type metallic glasses (MG), it has been shown that, by analogy with crystalline materials, it is reasonable to introduce for MG the concepts of characteristic deformation temperature T*, thermal and athermal components of flow stress (hardness) and ductile-brittle transition being characterized with two transition temperatures: Tdb t, the lowest temperature of macroscopic plasticity emergence, and Tdb 2 .~ 0.7 TΓ Β° ( TΓ Β° is the initial crystallization temperature) for all alloys tested. It has been found that alloying of MG with chromium and molybdenum leads to an increase of the thermal hardness component (whereas nickel promotes its lowering), the alloy strength and plasticity increase, the value of Tdb I is reduced and there is delocalization of the plastic flow. Study of the effects of segregation on MG fracture surfaces allowed one to elucidate the nature of short-range order local disturbances in the sites, where the localization of plastic flow is most intensive, and to suggest the possibility of considering these processes as the basis for a phenomenological model of strengthening of MG by alloying.
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