Accession Number:

ADA159886

Title:

The Densification of Molybdenum and Molybdenum Alloy Powders Using Hot Isostatic Pressing.

Descriptive Note:

Final technical rept.,

Corporate Author:

ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER WATERVLIET NY LARGE CALIBER WEAPON SYSTEMS LAB

Report Date:

1985-08-01

Pagination or Media Count:

66.0

Abstract:

This study was conducted to determine a superior erosion resistant gun barrel liner material with improved properties at higher temperatures. Four categories of powders were examined 1. TZM spherical containing 0.5 titanium, 0.08 zirconium, and 0.02 carbon wt. nominally, balance molybdenum Mo, produced by REP Rotating Electrode Process, PREP Plasma Rotating Electrode Process, and PMRS Plasma Melted and Rapidly Solidified 2. Mo reduced 2 and 5 microns 3. Mo-0.1 cobalt, co-reduced 4. Mo-5 wt. alumina A12O3, dispersion strengthened. Hot Isostatic Pressing HIP densification occurred at 15-30 Ksi, 1300-1600 C, for 1.5 to 3.0 hours. The TZM REPPREP powders 22074 microns were not fully densified even at 1600 C, 30 Ksi, 3 hours. Point particle contact prevented complete void elimination. TZM PMRS powder 24.7 microns achieved 99 percent of theoretical density while maintaining a small grain size 10.4 ASTM eq. Bend deflection and fracture energies were approximately three times those for PREP powder at a bend rupture strength of about 120 Ksi. Mo reduced and Mo-0.1 Co powders showed less or the same ductility with increasing HIP temperatures. Fractures were intergranular with decreased bend rupture and compression strength. The Mo-5A12O3 powder maintained a fine grain size 13 ASTM eq., but with fracture energies usually less than 0.6 in.-lbs. Included are results from bending and compression testing with metallographic and fracture mode interpretation.

Subject Categories:

  • Metallurgy and Metallography
  • Fabrication Metallurgy
  • Guns

Distribution Statement:

APPROVED FOR PUBLIC RELEASE