Solid state reactions and microstructural evolution of Al-Ni powders during high-energy ball milling

F. Cardellini, G. Mazzone, M. Vittori Antisari

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Abstract

The solid state reactions and the microstructural evolution during high-energy ball milling of Al-Ni powder mixtures in the composition range 25-75 at.% Al have been investigated. Experimental observations have shown that the microscopic mechanism underlying the alloying process in this system is the diffusion of Ni atoms in the Al-rich layers and that an important role is played by the oxygen contamination. An amorphous Al-rich phase containing a few at.% oxygen and with a Ni content not exceeding approximately 50 at.% has been detected in the equiatomic and Ni-rich samples milled for a few hours. This phase upon further milling transforms to a Ni-rich fee solid solution thus allowing one to by-pass the nucleation of Al3Ni in these samples. The self-sustaining high-temperature synthesis of the AlNi B2 phase has been found to occur over the 40-60 at.% range of Al concentration after about 3 h of milling. The same reaction has been observed in the Differential Scanning Calorimeter if equiatomic samples premilled for about 3 h (unreacted) are heated at a sufficiently high heating rate.
Original languageEnglish
Pages (from-to)1511 - 1517
Number of pages7
JournalActa Materialia
Volume44
Issue number4
DOIs
Publication statusPublished - 1996
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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