SOLIDIFICATION OF IRON BASE ALLOYS AT LARGE DEGREES OF UNDERCOOLING

Abstract

Results are presented of isothermal holding experiments on Fe-50% Cu alloy with silica inclusions present. In addition to rapid dendrite coarsening, the inclusions are 'pushed' by the growing dendrites; they collide, join and coalesce, and they coarsen by diffusion (Ostwald ripening). It is probable that similar effects occur during solidification of usual castings and ingots. A levitation melting, undercooling, and splat cooling device was modified to permit greater flexibility of operation and to incorporate ability to make chill plate castings (for study of mechanical properties as well as for structure). Dendrite arm spacing of commercial steel alloy castings made in this apparatus varies from about 50 microns for gas cooled specimens to less than 1 micron for splat cooled specimens. In work on Fe-Si-O alloy, no optically visible inclusions were found in splat cooled samples.

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Document Details

Document Type
Technical Report
Publication Date
Jul 15, 1968
Accession Number
AD0676865

Entities

People

  • M. Myers
  • Merton C. Flemings
  • W. E. Brower Jr.

Organizations

  • Massachusetts Institute of Technology

Tags

DTIC Thesaurus Topics

  • Compressive Strength
  • Cooling
  • Curing
  • Diffusion
  • Inclusions
  • Mechanical Properties
  • Physical Properties
  • Resilience
  • Solidification
  • Strength (Mechanics)
  • Supercooling

Fields of Study

  • Materials science

Readers

  • Powder metallurgy of Titanium alloys.

Technology Areas

  • Space