Development of Advanced Oxide Dispersion Strengthened Tungsten Heavy Alloy for Penetrator Application

Abstract

The effects of fabrication process parameters, including conditions for powder preparation, sintering, cyclic heat-treatment, swaging, and annealing processes, on microstructures and static/dynamic mechanical properties of ODS tungsten heavy alloys were investigated. The composition of ODS tungsten heavy alloys was designed as 94W-4.56Ni-1.14Co-0.3Y2O3 which show the highest strength at similar microstructural parameters based on the analysis of microstructures and mechanical properties. The two-stage sintered ODS tungsten heavy alloy showed finer tungsten grain size than those prepared by conventional liquid phase sintering with similar matrix volume fraction and tungsten/tungsten contiguity. Cyclic heat-treatment process was introduced after sintering process to increase the tensile strength and elongation by decreasing the tungsten/tungsten contiguity. The swaging and annealing processes of ODS tungsten heavy alloy increase the tensile strength with decreasing the elongation. High strain rate dynamic compressive tests were performed by Hopkinson pressure bar test equipment. The dynamic compressive strength of ODS tungsten heavy alloys was improved by addition of oxide dispersoids and by modification of composition from W-Ni-Fe to W-Ni-Co. At the same time, the adiabatic shear bands induced by high strain rate dynamic shear tests became narrower by the dispersion of Y2O3 and by the composition modification. The 94W-4.56Ni-1.14Co-0.3Y2O3 alloy, which was two-stage sintered, cyclic heat-treated, swaged, and annealed, shows high ultimate tensile strength of 1350MPa, moderate elongation of 5% and high compressive yield strength of 1800MPa under a high strain rate deformation of 3000/s. The 94W-4.56Ni-1.14Co-0.3Y2O3 ODS tungsten heavy alloy has been suggested as an advanced core material for kinetic energy penetrators and hard target penetrators.

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 2005
Accession Number
ADA474421

Entities

People

  • Chan B. Mo
  • Hee Y. Kim
  • Ho J. Ryu
  • Kyong H. Lee
  • Kyung T. Kim
  • Seung I. Cha
  • Soon H. Hong

Organizations

  • KAIST

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Deformation (Mechanics)
  • Grain Size
  • Heat Treatment
  • High Temperature
  • Kinetic Energy
  • Liquid Phases
  • Materials
  • Materials Engineering
  • Materials Science
  • Mechanical Properties
  • Mechanical Working
  • Phase
  • Strain Rate
  • Stresses
  • Tensile Properties
  • Tensile Strength
  • Yield Strength

Fields of Study

  • Materials science

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Powder metallurgy of Titanium alloys.