Synthesis of high strength bulk nanocrystalline alloys containing remaining amorphous phase

A. Inoue, C. Fan, A. Takeuchi

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Partial crystallization of cast bulk amorphous alloys in Zr-Al-Cu-Pd and Zr-Al-Cu-Pd-Fe systems was found to cause bulk nanocrystalline alloys with high tensile strength (σf). The nanostructure alloys consist of nanoscale bct-Zr2(Cu, Pd) surrounded by the remaining amorphous phase. The particle size and interparticle spacing of the compound are less than 10 and 1 nm, respectively. The crystallization of a ternary Zr60Al10Cu30 amorphous alloy occurs by the simultaneous precipitation of Zr2Cu and Zr2Al phases with large particle sizes of 400 to 500 nm and hence the addition of Pd is essential for formation of the nanostructure. The Pd has much larger negative heats of mixing against Zr and the resulting Zr-Pd atomic pair seems to act as preferential nucleation sites leading to the precipitation of Zr2(Cu, Pd). The nanostructure alloys in the cast cylinder of 4 to 5 mm in diameter keep good ductility in the volume fraction (Vf) range of the compound below 30 to 40%. The σf, Young's modulus (E) and fracture elongation (εf) increase from 1760 MPa, 81.5 GPa and 2.10%, respectively, at Vf=0% to 1880 MPa, 89.5 GPa and 2.17%, respectively, at Vf=40% for the Zr60Al10Cu20Pd10 alloy and from 1750 MPa, 81.1 GPa and 2.21%, respectively, at Vf=0% to 1850 MPa, 85.6 GPa and 2.28%, respectively, at Vf=28% for the Zr60Al10Cu15Pd10Fe5 alloy. The formation of the high-strength bulk nanostructure alloys in coexistence with the compound is presumably due to the reentrance of free volumes into the remaining amorphous phase caused by quenching from the supercooled liquid region.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalMaterials Science Forum
Volume307
Publication statusPublished - 1999 Jan 1

ASJC Scopus subject areas

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

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