The influence of quenching procedures on the kinetics of embrittlement in a Fe40Ni40B20 metallic glass

Abstract

The kinetics of mechanical stability (embrittlement), stress relief, and crystallization of Fe40Ni40B20 metallic glassy ribbons obtained by different melt spin quenching processes were investigated. Ribbons made with higher rate of quenching exhibit better mechanical stability over those made with lower quenching rate. The thermal stability, temperatures, and activation energies for crystallization of all ribbons, however, are identical. The rates of stress relief are higher for ribbons made with higher quenching rate. Values of activation energy for stress relief are about the same for all ribbons. These activation energies for stress relief are also close to those values reported for structural relaxation.

Structural relaxation and its influence on the elastic properties and notch toughness of Mg–Zn–Ca bulk metallic glass

“…Structural relaxation usually results in severe embrittlement for most of the metallic glasses [16][17][18][19]. Recently, the discovery of metallic glasses with very low T g [close to room temperature (T R )], such as Mg-and Ce-based metallic glasses, have initiated new interest, because structural relaxation may induce embrittlement in these alloys even at T R , thereby causing concerns about their potential applications [20][21][22][23][24].…”

Thermal embrittlement of Fe-based amorphous ribbons

“…Most of as-quenched metallic glasses show T db at lower than room temperature, and therefore, show good bending ductility at room temperature. T db in metallic glasses depends on alloy composition, quenching rate, and annealing conditions [12][13][14]. Annealing increases T db , and depending on the annealing temperature the specimen may become brittle at room temperature [12].…”

Mechanical Behavior of Fe- and Co-Based Amorphous Alloys after Thermal Action

“…It is important to keep in mind that loss of plasticity and ductile-brittle transition temperature Effect of heat treatment on the plasticity ε f of AAs: The difference between the alloys with respect to their ε f dependences is associated with different quenching rates upon their preparation: a higher rate of 2.6 × 10 6 K/c (for the Fe 53.3 Ni 26.5 B 20.2 alloy) leads to a one-stage decrease in plasticity, while a lower rate of 1.0 × 10 6 K/c (for the Co 28.2 Fe 38.9 Cr 15.4 Si 0.3 B 17.2 alloy) leads to two stages of decrease in ε f . It is important to keep in mind that loss of plasticity and ductile-brittle transition temperature in AAs depend on alloy composition, quenching rate, and annealing conditions [34][35][36][37]. In turn, the quenching rate is also related to the maximum thickness of the amorphous alloy formed during production on special equipment for melt quenching.…”