Mechanical Properties and Recrystallization Behavior of Electron-Beam-Melted Tungsten Compared with Arc-Melted Tungsten

Abstract

A study has been conducted of the properties of tungsten fabricated from three ingots consolidated by electron-beam melting. The study included purity as a function of number of melts, recrystallization a d grain growth behavior, low-temperature ductility, and high-temperature tensile and creep strength. The level of most metallic impurities in tungsten decreased with increasing number of electron-beam melts, the reduction being greatest for aluminum, iron, nickel, and silicon. The levels of interstitial impurities generally were not affected by remelting. Resistivity ratios for single crystals machined from ingot slices tended to increase on remelting. The recrystallization rates for worked, electron-beam- melted (EB-melted) tungsten were significantly higher than those observed earlier for arc-melted tungsten. The grain growth rates of EB-melted tungsten were higher than those reported previously for arc-melted tungsten, further reflecting the higher purity of the EB-melted materials. The activation energies for both recrystallization and grain growth in EB-melted tungsten were consistent with expected values assuming grain boundary self-diffusion to be the rate-controlling reaction. The ductile-brittle bend transition temperature for EB-melted tungsten is slightly higher in the worked condition than that reported for arc-melted tungsten. In the recrystallized conditions, the transition temperatures for EB- and arc-melted tungsten are similar. The tensile strength of EB-melted tungsten at 2500 to 4000 F is less than that of arc-melted tungsten. This is partly associated with the large grain size of EB-melted tungsten. However, when compared at the same grain size,

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1966
Accession Number
ADA400044

Entities

People

  • Walter R. Witzke
  • William D. Klopp

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Arc Melting
  • Chemical Analysis
  • Creep Strength
  • Ductile Brittle Transition
  • Electron Beam Melting
  • Geometry
  • Grain Growth
  • Grain Size
  • High Temperature
  • Low Temperature
  • Materials
  • Mechanical Properties
  • Tensile Properties
  • Tensile Strength
  • Transition Temperature
  • Transitions
  • Yield Strength

Fields of Study

  • Materials science

Readers

  • Materials Science and Engineering.
  • Metallurgy

Technology Areas

  • Directed Energy
  • Directed Energy - Pulsed-Laser Deposition
  • Microelectronics