Effect of the repeated melting of mother ingot on the stability of icosahedral phase precipitated from Zr-Al-Ni-Cu-Ag glass

Yan, Zhijie; Li, Jin-Fu; Wang, Honghua; He, Shunrong; Zhou, Yaohe

doi:10.1360/02ye0394

Cited by 4 publications

(3 citation statements)

References 17 publications

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“…The detailed preparation procedure was described elsewhere [16] . The glassy nature of specimens was verified by X-ray diffraction (XRD) using monochromatic CuKα radiation.…”

Section: Methodsmentioning

confidence: 99%

Phase transition in the Zr60Al15Ni25 bulk metallic glass subjected to rolling at room temperature

Yan

Zhou

et al. 2006

SCI CHINA SER E

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The microstructure evolution of the Zr 60 Al 15 Ni 25 metallic glass during rolling at room temperature is investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and high-resolution transmission electron microscopy (HREM). The results show that the values of full width at half maximum (FWHM) of the XRD patterns and exothermic enthalpy ∆H of DSC plots do not monotonically change with the variation of deformation degrees ε. As ε is not larger than 20%, the values of FWHM and ∆H are lower than that of the as-cast state. When ε reaches 30%, the values of FWHM and ∆H become larger than that of the as-cast state, while their values begin to decrease again as ε reaches about 85%. These results indicate that the reversible transitions between ordered and disordered atomic configurations occur during rolling, which is further verified by the HREM images. The reversible phase transition can be explained by the competition between the diffusion controlled reordering and shear-induced disordering during rolling.

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“…The detailed preparation procedure was described elsewhere [16] . The glassy nature of specimens was verified by X-ray diffraction (XRD) using monochromatic CuKα radiation.…”

Section: Methodsmentioning

confidence: 99%

Phase transition in the Zr60Al15Ni25 bulk metallic glass subjected to rolling at room temperature

Yan

Zhou

et al. 2006

SCI CHINA SER E

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“…High metallic luster indicates that the solidified surface is composed of glass phase, while a smoky surface indicates that the solidified surface is crystallized due to low glass-forming ability. As stated by Yan et al [10] , GFA strongly depends on the structure of the original master alloy buttons -microstructure characteristics are a critical factor in the first step of BMG fabrication. Accordingly, we observed the changes in solidification morphology and structure at different areas in the master alloy buttons before and after melt hydrogenation to elucidate the effect of hydrogen addition on the GFA of Zr 55 Cu 30 Ni 5 Al 10 alloys.…”

Section: Resultsmentioning

confidence: 99%

Hydrogen-induced amorphization of Zr-Cu-Ni-Al alloy

Dong

Zhang

et al. 2017

China Foundry

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Male, born in 1984, Doctor. He has been working in the field of advanced metallic materials with amorphous/glassy structure and their composites. In particular, his research focuses on developing new bulk metallic glasses used as hydrogen penetrating materials and hydrogen storage materials. T he limited glass-forming ability (GFA) of metallic glass restricts its application as a structural material. Although many laboratories have reported the development of large-sized (in many cases, centimeterplus) bulk metallic glasses (BMGs), the actual number of alloys suitable for commercial production is quite low [1] . It is of considerable practical significance to enhance the GFA of existing BMG-forming alloys. For these alloy systems, the nature and number of components and purity of elements are critical factors in terms of GFA and mechanical properties [2] . The GFA and properties of BMGs are also quite sensitive to the material's composition. Therefore, minor alloying additions play an important role in the glass formation, thermal stability, and comprehensive properties of BMGs [3] .Various elements have been employed to change the Abstract: Arc melting was utilized in this study to produce Zr 55 Cu 30 Ni 5 Al 10 alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidification structure and glass-forming ability of Zr 55 Cu 30 Ni 5 Al 10 alloy were determined by examining microstructures in different parts of the cast ingots. The results showed that different degrees of crystallization structures were obtained in the ascast button ingots after arc melting in high-purity Ar, and the cross-sectional solidification morphology of arcmelted ingots was found to consist of crystals with varying from the bottom up. By contrast, there were completely amorphous structures in the middle and upper areas of the as-cast button ingots fabricated by adding 10% H 2 to the high-purity Ar atmosphere. A clear solidification interface was found between the crystal and glass in the ascast button ingots, which indicates that hydrogen addition can enhance the Zr 55 Cu 30 Ni 5 Al 10 alloy's glass-forming ability. The precise mechanism responsible for this was also investigated.

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“…Namely, the thermal stability of the amorphous sample G12 against formation of I-phase is higher than that of the sample G0, which agrees with the change of T x12 . The effective activation energies for AI phase transformation are much smaller than that for the transformation from amorphous to the stable CuZr 2 -and NiZr 2 -like phases (about 356 kJ/mol [23]). This indicates that the structure of I-phase is more similar to the amorphous matrix.…”

Section: Transformation Kinetics Under Isochronal Conditionsmentioning

confidence: 84%