Effect of tensile stress on the annealed structure of a metallic glass
The low-temperature (120/sup 0/--245 /sup 0/C) structural relaxation of Metglas/sup R/ 2826B (Ni/sub 49/Fe/sub 29/P/sub 14/B/sub 6/Si/sub 2/) amorphous alloy was investigated for samples subjected to a tensile stress in the range of 20--400 MPa during annealing. The stress-annealed samples demonstrated a much smaller increase of microhardness than was observed in similarly annealed ribbons without a stress. Further heat treatment of the stress-annealed specimens, this time without the stress, was capable of increasing the microhardnesses of only some ribbons to values equal to those of samples similarly heat treated initially without a stress. An additional exothermic peak in the differential scanning calorimetry (DSC) thermograms of the stress-annealed specimens indicated the presence of a more disordered structure at room temperature, which was found to correlate with the lower microhardness values. Otherwise, those artifacts of the DSC thermograms that were characteristic of samples annealed without a stress were still present in the stress-annealed ribbons. No effect on the crystallization temperature was noted but the glass transition temperature was increased in the stress-annealed case with respect to values attained when the stress was absent during heat treatment. A reduction in the degree of embrittlement of those samples annealed with a tensile stress was a further indication of more disorder in the stress-annealed ribbons.
- Research Organization:
- Materials Science Program, Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627
- OSTI ID:
- 6421146
- Journal Information:
- J. Mat. Res.; (United States), Journal Name: J. Mat. Res.; (United States) Vol. 2:4; ISSN JMREE
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101 -- Metals & Alloys-- Preparation & Fabrication
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ANNEALING
BORON ALLOYS
EMBRITTLEMENT
HARDNESS
HEAT TREATMENTS
IRON ALLOYS
MECHANICAL PROPERTIES
METALLIC GLASSES
MICROHARDNESS
NICKEL ALLOYS
NICKEL BASE ALLOYS
PHOSPHORUS COMPOUNDS
RELAXATION
SILICON ALLOYS
STRESS RELAXATION