Journal article
Strain, stress and stress relaxation in oxidized ZrCuAl-based bulk metallic glass
Surface engineering of Zr 51.3 Al 8.5 Cu 31.3 Ni 4 Ti 4.9 bulk metallic glass (BMG) by gaseous oxidizing below the glass-transition temperature is investigated as a means to introduce compressive residual stress in the surface region. The ZrCuAl-based BMG was exposed to an extremely low oxygen partial pressure of 10−41 bar at 600 K for 60 h.
The oxidizing treatment led to the formation of an internal oxidation zone, consisting of finely dispersed nano-crystalline cubic ZrO 2 (c-ZrO2 ), metallic regions inclined with the surface and Cu-hillocks at the surface. The stresses introduced by the volume expansion associated with oxidation were evaluated from i) the lattice strains within c-ZrO2 , as determined with an X-ray diffraction (XRD) based method, and ii) strain-relaxation as a response to annular focused ion beam (FIB) milling, as monitored with digital image correlation (DIC).
XRD analysis yielded -1.5 GPa (compressive stress) in the nano-crystalline c-ZrO2 , while the strain relaxation monitored with FIB-DIC analysis indicated compressive residual stresses of −1.4 GPa in the internal oxidation zone. The strains and stresses determined with the independent measurement methods are discussed.
The quantitative macro-strains are discussed in relation to the microstructural features and stress relaxation mechanisms during evolution of the internal oxidation zone.
Language: | English |
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Year: | 2020 |
Pages: | 674-685 |
ISSN: | 13596454 and 18732453 |
Types: | Journal article |
DOI: | 10.1016/j.actamat.2020.09.049 |
ORCIDs: | Haratian, Saber , Nießen, Frank , Grumsen, Flemming Bjerg , Villa, Matteo , Christiansen, Thomas L. and Somers, Marcel A. J. |
FIB-DIC method Gaseous Oxidizing Residual stress Self-healing mechanism X-ray diffraction sin 2 ψ method ZrCuAl-based bulk metallic glass