Accession Number : AD0664887

Title :   STABILITY OF TUNGSTEN AND THORIA DISPERSIONS IN BERYLLIUM,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Watts,C. R.

Report Date : DEC 1967

Pagination or Media Count : 18

Abstract : Two candidate refractory materials were selected for a study of the feasibility of producing fine stable dispersions in beryllium. The dispersants used, tungsten and thoria, were introduced by means of powder metallurgical methods. Mixtures of tungsten or thoria with beryllium powder were prepared by the decomposition of ammonium metatungstate or thorium nitrate under hydrogen after precipitation from an aqueous solution containing the powder. As the hot-pressing or sintering temperature for the compositions containing tungsten was raised above 750C, the tungsten reacted to produce WBe12. As the temperature was raised above 850C, WBe22 began to form. Above 1100C, WBe22 was the only beryllide present. The reactions were apparently irreversible. The dispersions of thoria reacted above 750C to produce ThBe13 as the dispersed phase. No other thorium beryllides were produced or expected at higher consolidation temperatures. The temperature at which the starting materials react to produce a beryllide is sufficiently above the 700C usual maximum use temperature for beryllium so that composites may be used containing elemental tungsten or thoria or their respective beryllides. (Author)

Descriptors :   (*BERYLLIUM, *DISPERSION HARDENING), REINFORCING MATERIALS, REFRACTORY MATERIALS, TUNGSTEN, THORIUM COMPOUNDS, DIOXIDES, POWDER METALLURGY, HOT PRESSING, SINTERING, INTERMETALLIC COMPOUNDS, TUNGSTEN COMPOUNDS, BERYLLIUM COMPOUNDS, PHASE STUDIES

Subject Categories : Laminates and Composite Materials
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE