Alloying and microstructural changes in platinum-titanium milled and annealed powders

Kasonde Maweja, M. J. Phasha, Y. Yamabe-Mitarai

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Equiatomic platinum-titanium powder mixtures were processed by high energy ball milling under argon atmosphere and sintered under vacuum. Evolution of the crystal structures and microstructures of the products formed were investigated by XRD and SEM techniques, respectively. The HCP crystals of Ti were first deformed and then a disordered metastable FCC Pt(Ti) solid solution was formed during milling due to semi-coherency of FCC lattices. A nanostructured Pt(Ti) product was formed after long milling time, which contained 44-47 at.% Ti and 53-56 at.% Pt. An ordered PtTi intermetallic was formed by annealing the metastable Pt(Ti) at temperature above 1300 °C. The crystal structure and microstructure of the TiPt phase depended on the milling time, annealing temperature and the cooling rate. The B19 PtTi plate martensite was formed after annealing at 1500 °C and quenching at a cooling rate of 23 °C/min to 200 °C/min for short time milled products. The width of martensite features was smaller at high cooling rate. In PtTi products milled for longer time, no martensitic transformation was observed on cooling the annealed samples. Small amounts of Pt 5Ti 3 were formed in the powders milled for 16 h or more, followed by annealing at 1500 °C and furnace cooling at ∼2 °C/min.

Original languageEnglish
Pages (from-to)167-175
Number of pages9
JournalJournal of Alloys and Compounds
Volume523
DOIs
Publication statusPublished - 2012 May 15
Externally publishedYes

Keywords

  • Annealing
  • Ball milling
  • Martensite
  • Mechanical alloying
  • Ti-Pt

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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