Effect of Crystallization on the Mechanical Properties of Zr{sub 56.7}Cu{sub 15.3}Ni{sub 12.5}Nb{sub 5.0}Al{sub 10.0}Y{sub 0.5} Bulk Amorphous Alloy

Journal Article · Tue Mar 15 00:00:00 EST 2005 · Materials Science and Engineering. A. Structural Materials: Properties, Microstructure and Processing

DOI:https://doi.org/10.1016/j.msea.2004.11.045· OSTI ID:15011429

Das, Kakoli; Bandyopadhyay, Amit; Gupta, Yogendra M

Effects of crystallization behavior on the mechanical properties of Zr{sub 56.7}Cu{sub 15.3}Ni{sub 12.5}Nb{sub 5.0}Al{sub 10.0}Y{sub 0.5} based bulk amorphous alloy (BAA) were studied. Differential scanning calorimetry (DSC) in Ar environment showed three-exothermic peaks at 395, 472 and 659.5 C and one-endothermic peak at 852 C. Following DSC study, as received BAA samples were heat-treated in vacuum at six different temperatures 300, 450, 600, 700, 800 and 850 C. Heat-treated samples were characterized using Vickers microhardness, X-ray diffraction (XRD), differential scanning calorimetry and field emission scanning electron microscopy (FESEM) to study crystallization behavior. It is found that samples heat-treated above the second (472 C) and third (659.5 C) exothermic peaks show high microhardness values compared to the as processed samples, and brittle cracking along the indent diagonal. As processed samples show clear evidence of shear banding. FESEM examination revealed existence of nano-scale precipitates for samples heat-treated at 600 and 700 C, while micro-scale precipitates for 850 C samples. Quasi-static compression tests showed compressive strain to failure decrease with heat-treated samples compared to as received ones. Fracture morphology of the compression test samples changes from vein pattern for as received to flat facets with multiple cracks for heat-treated samples. Indentation fracture toughness values decrease almost an order of magnitude for heat-treated samples compared to as received samples.

• Research Organization: Pacific Northwest National Lab., Richland, WA (US), Environmental Molecular Sciences Laboratory (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15011429
• Journal Information: Materials Science and Engineering. A. Structural Materials: Properties, Microstructure and Processing, Vol. 394, Issue 1-2; Other Information: PBD: 15 Mar 2005
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
CALORIMETRY
COMPRESSION
CRYSTALLIZATION
FIELD EMISSION
FRACTURE PROPERTIES
FRACTURES
MECHANICAL PROPERTIES
MICROHARDNESS
MORPHOLOGY
SCANNING ELECTRON MICROSCOPY
SHEAR
STRAINS
X-RAY DIFFRACTION
ENVIRONMENTAL MOLECULAR SCIENCES LABORATORY
BULK AMORPHOUS ALLOYS
CRYSTALLIZATION BEHAVIOR
PHASE TRANSFORMATION