Relation between icosahedral short-range ordering and plastic deformation in Zr–Nb–Cu–Ni–Al bulk metallic glasses

Enhanced plasticity by introducing icosahedral medium-range order in ZrCuNiAl metallic glass

“…It is worthy to mention that Setyawan et al [22] and Zhu et al [19] also found good compressive plasticity in the Zr 65 Cu 12.5-Ni 10 Al 7.5 Pd 5 and Zr 66 Nb 4 Cu 13.5 Ni 8.5 Al 8 BMGs, which exhibit the similar crystallization behavior as in the present work, i.e twostep of crystallization with initial formation of QCs. It is argued that the significant plasticity is attributed to the occurrence of nano-crystallization during deformation.…”

“…Zhu et al [19] recently reported that the room temperature plasticity of a ZrCuNiAl BMG could be significantly enhanced by the introduction of icosahedral short-range ordering in the as-cast alloy with the addition of Nb. Similar phenomena were also found in other BMG systems, such as ZrCuNiAlTa [20,21] and ZrCuNiAlPd [22].…”

“…These BMGs usually follow a multi-step crystallization with the initial formation of quasicrystals (QCs), implying the existence of strong icosahedral short/medium-range order clusters in amorphous phase [23,24]. It is suggested that this structural heterogeneity at atomic scale could influence the free volume distribution and therefore the shear band formation and propagation, and finally the plasticity of the BMGs [19,21]. However, in a recent work, Zhang et al [25,26] reported that the icosahedral clusters play a negative role in plasticity of BMGs, as the decrease in the number of icosahedral clusters could enhance the plasticity of Zr-based BMGs.…”

Enhanced plasticity in Zr-based bulk metallic glasses by hydrogen

“…Very recently, plastic BMGs in some special systems were also developed [7e9]. Several mechanisms have been proposed to explain the plastic deformation of BMGs, i.e., large Poisson's ratio [7,9], nanocrystallization induced before deformation [10,11] or during deformation [12], free volume [13] and short-or medium-range order [14,15]. Hydrogen is usually a harmful element in a wide range of crystalline metals.…”

Crystallization and compressive behaviors of Ti40Zr25Ni8Cu9Be18 BMG cast from different liquid states

“…The icosahedral cluster will lead to the precipitation of fcc Zr 2 Ni phase during deformation and the Zr 2 Ni phase will cause the multi-shear bands. Moreover, icosahedrial SRO-mediated free volume is concentrated in certain zones, where the activation of shear transformations is facilitated so as to form multiple shear bands [19]. Actually, besides the activation energy of shear transition zone (STZ), the sliding velocity of shear band would also influence the plasticity of metallic glass.…”