Cryo-Casting for Controlled Decomposition of Cu-Zr-Al Bulk Metallic Glass into Nanomaterials: Implications for Design Optimization
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In: ACS Applied Nano Materials, Vol. 4.2021, No. 8, 19.07.2021, p. 7771-7780.
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TY - JOUR
T1 - Cryo-Casting for Controlled Decomposition of Cu-Zr-Al Bulk Metallic Glass into Nanomaterials
T2 - Implications for Design Optimization
AU - Sarac, Baran
AU - Kim, Jeong Tae
AU - Ivanov, Yurii P.
AU - Soprunyuk, Viktor
AU - Ketov, Sergey V.
AU - Schranz, Wilfried
AU - Hong, Sung Hwan
AU - Kim, Ki Buem
AU - Greer, A. Lindsay
AU - Eckert, Jürgen
N1 - Publisher Copyright: © 2021 American Chemical Society.
PY - 2021/7/19
Y1 - 2021/7/19
N2 - Cryo-cooled copper-mold suction casting reveals an unexpected phase separation (PS) in Cu46Zr46Al8 bulk metallic glass (BMG) by controlled atomic diffusion. The decomposed alloy cryo-cast to 193 K exhibits a remarkably lower free volume than the alloy cast to room temperature manifested by dilatometry. An unusual endotherm after the onset of relaxation registered by differential scanning calorimetry and compositional homogenization occurring on long time scales upon post-heat treatment even above the glass-transition temperature confirm the stability of the decomposed state against crystallization. As revealed by scanning transmission electron microscopy and energy-dispersive X-ray analysis, single-stage PS (cryo-cast to 193 K) results in distinct and evenly dispersed nanoscale Cu- and Zr-rich regions, whereas two-stage PS (cast to 298 K) involves further decomposition of existing Cu- and Zr-rich regions on a finer scale. Notably, PS accounts for macroscopic compressive plasticity at no expense of fracture strength. This study opens opportunities for the design optimization of homogeneously dispersed amorphous nanostructures of controllable size and composition in BMGs by single- or multistage decomposition through mold temperature control.
AB - Cryo-cooled copper-mold suction casting reveals an unexpected phase separation (PS) in Cu46Zr46Al8 bulk metallic glass (BMG) by controlled atomic diffusion. The decomposed alloy cryo-cast to 193 K exhibits a remarkably lower free volume than the alloy cast to room temperature manifested by dilatometry. An unusual endotherm after the onset of relaxation registered by differential scanning calorimetry and compositional homogenization occurring on long time scales upon post-heat treatment even above the glass-transition temperature confirm the stability of the decomposed state against crystallization. As revealed by scanning transmission electron microscopy and energy-dispersive X-ray analysis, single-stage PS (cryo-cast to 193 K) results in distinct and evenly dispersed nanoscale Cu- and Zr-rich regions, whereas two-stage PS (cast to 298 K) involves further decomposition of existing Cu- and Zr-rich regions on a finer scale. Notably, PS accounts for macroscopic compressive plasticity at no expense of fracture strength. This study opens opportunities for the design optimization of homogeneously dispersed amorphous nanostructures of controllable size and composition in BMGs by single- or multistage decomposition through mold temperature control.
KW - cryo-casting
KW - electron microscopy
KW - heat treatment
KW - metallic glass
KW - nanostructures
KW - phase separation
KW - structural relaxation
UR - http://www.scopus.com/inward/record.url?scp=85111584696&partnerID=8YFLogxK
U2 - 10.1021/acsanm.1c01055
DO - 10.1021/acsanm.1c01055
M3 - Article
AN - SCOPUS:85111584696
VL - 4.2021
SP - 7771
EP - 7780
JO - ACS Applied Nano Materials
JF - ACS Applied Nano Materials
SN - 2574-0970
IS - 8
ER -
