Crystallization kinetics of Zr65Ag5Cu12.5Ni10Al7.5 glassy powders produced by ball milling of pre-alloyed ingots

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 513; pp. 279 - 285
• Main Authors: Prashanth, K.G., Scudino, S., Surreddi, K.B., Sakaliyska, M., Murty, B.S., Eckert, J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-07-2009; Elsevier
• Subjects: Annealing; Applied sciences; Calorimetry; Elasticity. Plasticity; Exact sciences and technology; Heat treatment; Kinetics; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metallic glasses; Metals. Metallurgy; Powder metallurgy; Powder metallurgy. Composite materials; Production techniques; Technology; Metallic glasses; Calorimetry; Kinetics; Powder metallurgy; Viscosity; Differential scanning calorimetry; Annealing; Ball mill; Crystallization; Compression test; Thermal stability; Transition metal alloy; Activation energy; Zirconium base alloys
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2009.01.075

Ball milling was employed to produce Zr65Ag5Cu12.5Ni10Al7.5 glassy powder from pre-alloyed mixtures of crystalline intermetallic compounds. Differential scanning calorimetry (DSC) in isochronal as well as in isothermal modes was used to study the thermal stability and the crystallization kinetics of the glassy powder. The activation energy for crystallization was calculated using isothermal and isochronal DSC data as well as from viscosity measurements, which lead to values of the activation energy ranging between 298 and 314
kJ/mol. Johnson–Mehl–Avrami analysis shows that the transformation is a diffusion controlled three-dimensional process and the crystallization proceeds with increasing nucleation rate at annealing temperatures within the super-cooled liquid region. To test the effectiveness of the glassy powder as reinforcement in Al-based metal matrix composites, bulk specimens consisting of pure Al powder blended with 50
vol.% of Zr65Ag5Cu12.5Ni10Al7.5 glassy powder were synthesized by powder metallurgy. Room temperature compression tests reveal that the strength increases from 155
MPa for pure Al to 235
MPa for the composite with 50
vol.% of glass reinforcement.