Phase evolution and microtwins in the Ni-Al multilayers upon annealing and laser mixing

P. Bhattacharya, K. Chattopadhyay, P. Bellon, K. N. Ishihara

Research output: Contribution to journalArticle

Abstract

Multilayers of Ni and Al of 1:1 ratio, 50nm periodicity, were deposited using sputtering. Progress in phase evolution in these films upon annealing and laser mixing has been studied. Characterization of the as deposited and the treated states were carried out with X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) techniques. As-deposited state reveals the presence of elemental Ni and Al with grain size comparable to the film thickness. Phase evolution upon annealing occurs in several stages determined by the kinetics of nucleation and growth. Al3Ni and Al3Ni2 initially form at 673K and transforms to a mixture of AlNi and Ni3Al at about 873K. Films were also treated with nanosecond laser pulse of 20-200mJ energy with spot size of 1 and 1.5mm. The major phase obtained after laser irradiation is B2 with grain size increasing with increasing imparted pulse energy. In addition to B2, microtwins and tweed microstructures are often observed. The origin and the nature of twins have been analysed in details. Formation of this type of microstuctures in polycrystalline thin films and with Ni content <62at.% has not been reported previously.

Original languageEnglish (US)
Pages (from-to)1277-1284
Number of pages8
JournalMaterials Science and Engineering A
Volume375-377
Issue number1-2 SPEC. ISS.
DOIs
StatePublished - Jul 1 2004

Keywords

  • B2
  • L1
  • Martensite
  • Microtwins
  • Multilayers
  • Ni-Al

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

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