STP725

    Irradiation-Induced Precipitation in Binary Palladium-Refractory Metal Alloys

    Published: Jan 1981


      Format Pages Price  
    PDF Version (460K) 17 $25   ADD TO CART
    Complete Source PDF (13M) 17 $66   ADD TO CART


    Abstract

    A study of irradiation-induced precipitation (IIP) has been carried out on a series of palladium-based alloys containing tungsten, molybdenum, tantalum, and niobium, irradiated with 400-keV protons over the temperature range 65 to 750°C. IIP has been observed in the palladium-tungsten (Pd-W) alloy containing 10 and 18 atomic percent tungsten and in a Pd-10 atomic percent molybdenum alloy. In the Pd-W system, irradiation at temperatures of 300°C and above gives rise to a second phase tungsten precipitate associated with interstitial dislocation loops, while temperatures in excess of 200°C induce the formation of a tetragonal-ordered phase of the type Pd8W. IIP has been observed in the Pd-10Mo alloy, but only in specimens irradiated at 65°C. The irradiation gives rise to a molybdenum precipitate associated with interstitial dislocation loops, analogous to the occurrence of tungsten in the Pd-W alloy. IIP has not been observed in the palladium-tantalum and palladium-niobium systems at interstitial dislocation loops which form in the 200 to 400°C temperature range. The microstructures observed are described in detail and discussed in the light of recently proposed mechanisms of IIP. It is concluded that the IIP of tungsten and molybdenum at interstitial dislocation loops must occur as a consequence of strong interstitial solute atom binding, and that the observation of this phenomenon in the percent tungsten alloy represents the first clear-cut example of such binding in an alloy containing an oversized solute.

    Keywords:

    irradiation-induced precipitation, palladium-tungsten, palladium-molybdenum, palladium-niobium, palladium-tantalum, solute-size misfit, dislocation loops


    Author Information:

    Weaver, L
    Post-doctoral researcher and professor, School of Engineering and Applied Science, University of CaliforniaRank Xerox Lte. Engineering Group, Los AngelesWelwyn Garden City, Calif.Herts.

    Ardell, AJ
    Post-doctoral researcher and professor, School of Engineering and Applied Science, University of CaliforniaRank Xerox Lte. Engineering Group, Los AngelesWelwyn Garden City, Calif.Herts.


    Paper ID: STP28239S

    Committee/Subcommittee: E10.02

    DOI: 10.1520/STP28239S


    CrossRef ASTM International is a member of CrossRef.