Solid-state phase separation in Zr–Y–Al–Co metallic glass

Abstract

The present study shows that the as-melt-spun Zr28Y28Al22Co22 amorphous ribbon undergoes solid-state phase separation into Zr- and Y-rich regions when heated below the glass transition temperature (Tg). Dynamic mechanical measurements show that two types of low-temperature relaxation occur below Tg, and transmission electron microscopy observation confirms the solid-state phase-separated microstructure. The diffusion coefficient of solid-state phase separation is calculated by the measured separation distance.

Passivation of native defects of ZnO by doping Mg detected through various spectroscopic techniques

“…34 The observed modes are compared with both theoretically and experimentally reported values and are found to be in between the limit of theoretically and experimentally reported values. 8,35 A prominent band at 908 cm À1 observed in ZnO corresponds to the bending vibration of V Zn -H ABOk . 8 Besides the above common modes, a few additional modes are also observed at 856, 1512 and 3690 cm À1 in Mg doped ZnO.…”

Multiscale structures and phase transitions in metallic glasses: A scattering perspective

“…People support that the phase separation is possible for alloys with atomic pairs of the positive heat of mixing. [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] The strong positive heat of mixing among their constituent elements dramatically reduces the GFA, so the alloys in Table 1 are mainly ribbon size or limited bulk size. As listed in Table 2, the alloys of the strong negative heat of mixing could form bulk-size MGs.…”

“…Sample size Atomic pairs and heat of mixing/kJ•mol −1 Zr 60−x Y x Al 15 Ni 25 , 15 ≤ x ≤ 35 [41] ribbon and bulk (≤ 3 mm) Z-Y (+9) Zr 33 Y 27 Al 15 Ni 25 [42] La 27.5 Zr 27.5 Al 25 Cu 10 Ni 10 [43] ribbon Zr-La (+13) Y 28 Ti 28 Al 24 Co 20 [44] ribbon Y-Ti (+15) Ti-Y-Al-Co [45] ribbon Ti-Y (+15) Zr 28 Y 28 Al 22 Co 22 [45] Zr-Y (+9) Ni-Nb-Y [46] ribbon Nb-Y (+30) Cu-Zr-Y-Al [47] ribbon Zr-Y (+35) Cu-(Zr, Hf)-(Gd,Y)-Al [48] ribbon Zr-Y (+35) Hf-Y (+11) Zr-Gd (+9) Hf-Gd (+11) Nd-Zr-Al-Co [49] ribbon Nd-Zr (+10) Zr-Y-Al-Co [50] ribbon Zr-Y (+35) Zr-(Ce, Pr, Nd)-Al-Ni [51] ribbon Zr-RE (+) Gd-Ti-Al-Co/Cu [52] ribbon Gd-Ti (+15) Gd-Hf-Co-Al [53] ribbon Gd-Hf (+11) Gd-(Hf, Ti, Y)-Co-Al [54] Gd-Ti (+15) Gd-Y (0) Zr-Gd-Al-Ni [55] ribbon and bulk (1 mm) Zr-Gd (+9) Zr-Cu-Co-Al [56] bulk (1 mm) Co-Cu (+9) Zr-Cu-Ni-Al-Fe [57] bulk (≤ 2 mm) Fe-Cu (+13) which are responsible for the occurrence of amorphous phase separation before crystallization. Since the 1990s, Johnson et al [65] also observed amorphous phase separation when annealing Zr-based multicomponent MGs in the supercooled liquid region.…”