Journal article
Effect of hafnium incorporation on the crystallization and mechanical behavior of a Zr-based bulk amorphous alloy
Materials science & engineering. A, Structural materials : properties, microstructure and processing, Vol.477(1), pp.233-242
2008
Handle:
https://hdl.handle.net/2376/116061
Abstract
The crystallization and mechanical behavior of a hafnium-containing bulk amorphous alloy (Hf
28.35Zr
28.35Cu
15.3Ni
12.5Nb
5.0Al
10.0Y
0.5) was investigated and compared with a Hf-free alloy (Zr
56.7Cu
15.3Ni
12.5Nb
5.0Al
10.0Y
0.5) to understand the role of hafnium. Although the overall behavior of both alloys has similarities both in the as-received and heat-treated states, details of the physical, thermal, and mechanical properties are influenced by the incorporation of hafnium. Differential scanning calorimetry (DSC) results for the hafnium-containing alloy showed a glass transition at 440
°C and three exothermic peaks at 511, 559, 664
°C which correspond to primary and secondary crystallization. The increase in glass transition and the first crystallization temperature, compared to the Hf-free alloy, indicates stabilization of the amorphous state. Samples were heat-treated at various temperatures to examine the crystallization of various intermetallic phases. The phases were identified using X-ray diffraction (XRD) and the sizes varied between 100 and 200
nm, as observed by field emission scanning electron microscopy (FESEM), for samples heat-treated at 700 and 800
°C. The Vickers microhardness increased with heat-treatment from 5.2 to 7.2
GPa. Quasi-static compression tests showed decrease in failure stresses from 1843
MPa (as-received) to 994
MPa (heat-treated at 535
°C). The failure stress increased to 1661
MPa for the sample heat-treated at 800
°C, similar to the Hf-free alloy. Fracture morphologies changed from typical vein-type in as-received samples to smooth facets in heat-treated samples indicating embrittlement. Failure mechanism changes from shear banding in the as-received amorphous samples to void formation and coalescence in the heat-treated samples.
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Details
- Title
- Effect of hafnium incorporation on the crystallization and mechanical behavior of a Zr-based bulk amorphous alloy
- Creators
- F Baldwin - Institute for Shock Physics, Washington State University, Pullman, WA 99164, USAN.V Ravi Kumar - Institute for Shock Physics, Washington State University, Pullman, WA 99164, USAK Das - Institute for Shock Physics, Washington State University, Pullman, WA 99164, USAA Bandyopadhyay - Institute for Shock Physics, Washington State University, Pullman, WA 99164, USAY.M Gupta - Institute for Shock Physics, Washington State University, Pullman, WA 99164, USA
- Publication Details
- Materials science & engineering. A, Structural materials : properties, microstructure and processing, Vol.477(1), pp.233-242
- Academic Unit
- Physics and Astronomy, Department of; Mechanical and Materials Engineering, School of
- Publisher
- Elsevier B.V
- Identifiers
- 99900547605801842
- Language
- English
- Resource Type
- Journal article