In-situ observation of an unusual phase transformation pathway with Guinier-Preston zone-like precipitates in Zr-based bulk metallic glasses

Journal Article · Sat Nov 16 00:00:00 EST 2019 · Journal of Alloys and Compounds

DOI:https://doi.org/10.1016/j.jallcom.2019.153049· OSTI ID:1601430

Dong, Weixia ^[1]; Ge, Jiacheng ^[1]; Ke, Yubin  ^[2]; Ying, Huiqiang ^[1]; Zhu, Li ^[3]; He, Haiyan ^[4]; Liu, Sinan ^[1]; Lu, Chenyu ^[4]; Lan, Si  ^[5]; Almer, Jon ^[6]; Ren, Yang ^[6]; Wang, Xun-Li  ^[4]

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1. Nanjing Univ. of Science and Technology (China). Herbert Gleiter Inst. of Nanoscience, School of Materials Science and Engineering
2. Chinese Academy of Sciences (CAS), Dongguan (China). China Spallation Neutron Source, Branch, Inst. of High Energy Physics
3. Nanjing Univ. of Aeronautics and Astronautics (China). College of Materials Science and Technology
4. City Univ. of Hong Kong (China)
5. Nanjing Univ. of Science and Technology (China). Herbert Gleiter Inst. of Nanoscience, School of Materials Science and Engineering; City Univ. of Hong Kong (China)
6. Argonne National Lab. (ANL), Argonne, IL (United States)

The pathway of amorphous-to-crystalline phase transformation in Zr_52.5Cu_17.9Ni_14.6Al₁₀Ti₅ bulk metallic glasses was studied using a suite of in-situ techniques. Multi-scale structure evidence reveals a five-stage pathway, analogous to the non-equilibrium transformation process with Guinier-Preston zones during aging in precipitation-hardened alloys, by the following sequence upon isothermal annealing the alloy in the supercooled liquid region: polyamorphous phase transition, chemical phase separation, the formation of a poorly-ordered metastable phase, and the formation of a final crystalline product. The changeable incubation periods at different annealing temperatures, and the abrupt multi-scale structure changes, as well as a latent heat release in the calorimetric measurements, support the first-order nature of the phase transformation at early stages. The structure evolution in real-space indicates that the enhancement of cluster connectivity on the medium-range scale plays essential roles in the early stages of the phase transformation, while the interface-limited ordering dominates the later stages. The experimental results suggest the phase transformation pathway with "Guinier-Preston zone-like" precipitates accompanied by the kinematic development of core-shell structures of diffuse interfaces with order parameters gradients, enabling the step-by-step decrease of free energy of the alloy system during phase transformation, which might be a universal behavior for alloys with excellent glass-forming ability.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Contributing Organization: Research Grants Council (RGC) of Hong Kong; National Natural Science Foundation of China; National Natural Science Foundation of Jiangsu Province; Fundamental Research Funds for the Central Universities
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1601430
• Alternate ID(s): OSTI ID: 1702830
• Journal Information: Journal of Alloys and Compounds, Vol. 819, Issue C; ISSN 0925-8388
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Guinier-Preston zone
bulk metallic glasses
electron microscopy
neutron scattering
phase transformations pathway
synchrotron