STRUCTURAL CONSIDERATIONS IN DEVELOPING REFRACTORY METAL ALLOYS

Abstract

Progress made in applying advanced techniques and structural concepts to the problem of strengthening the Group VI-A metals, Cr, Mo, and W, is examined. At low temperatures, T/Tm<0.2, dislocations and grain boundaries play an important role. High strength values and the marked temperature and strain-rate dependence of the yield stress exhibited by the Group VI-A metals in this range are consistent with the idea that dislocation movement is rate controlling and thermally activated. Dislocation mobility considerations also point to the existence of high stresses in advance of a moving crack, and, consequently, a low level of crack propagation resistance. A second factor contributing to the brittleness of Group VI-A metals is grain-boundary weakness caused by interstitial atom impurities. Studies of rhenium additions to the Group VI-A metals suggest that the brittleness tendency can be inhibited by alloying. The origin of this effect has not been decided.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jan 31, 1963
Accession Number
AD0407394

Entities

People

  • G. T. Hahn
  • Robert Isaac Jaffee

Organizations

  • Battelle Memorial Institute

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Chemistry
  • Chromium
  • High Temperature
  • Low Temperature
  • Materials
  • Materials Engineering
  • Materials Processing
  • Materials Science
  • Mechanical Properties
  • Mechanical Working
  • Metallurgy
  • Refractory Metals
  • Sheet Metal
  • Solid Solutions
  • Tensile Properties
  • Transition Temperature
  • Yield Strength

Readers

  • Materials Science (Mechanical Engineering).
  • Materials Science and Engineering.
  • Mycotoxin ecology in Amazonian ecosystems.