The Collapse of Defect Cascades to Dislocation Loops in Cu3Au

    Published: Jan 1987

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    We report a systematic experimental study of the conditions leading to vacancy dislocation loop formation at the sites of defect cascades produced by ion irradiations. Transmission electron microscopy (TEM) techniques and the ordered alloy Cu3Au were employed to measure the probability of dislocation loop formation as functions of irradiating ion mass (Ar+, Cu+, and Kr+), ion energy (50 and 100 keV), and sample irradiation temperature (30 and 300 K). Disordered zones in the ordered alloy were produced at every defect cascade site and imaged in dark-field superlattice reflections. Dislocation loops were imaged in fundamental reflections in the same sample areas to produce a very accurate measurement of the probability of the collapse of each cascade to a dislocation loop, within a large set (∼200) of defect cascades for each irradiation condition. The size distributions of dislocation loops and disordered zones were also measured for selected irradiation conditions. A central result was that defect cascades collapse to dislocation loops with significant probability (∼0.5) even at sample irradiation temperatures of 30 K. Other observations include an increasing collapse probability with increasing cascade energy density (increasing ion mass) and with increasing sample irradiation temperature. However no additional collapse was observed upon annealing from 30 to 300 K, and no increase in collapse probability was observed upon increasing the bombarding ion energy from 50 to 100 keV. Disordered zone sizes also increased with increasing ion mass and with increasing sample irradiation temperature (30 to 300 K).


    collision cascades, dislocation loops, Cu, 3, Au, transmission electron microscopy (TEM), ion irradiations

    Author Information:

    Black, TJ
    Graduate student and senior research fellow at Wolfson College, University of Oxford, Oxford,

    Jenkins, ML
    Graduate student and senior research fellow at Wolfson College, University of Oxford, Oxford,

    English, CA
    Irradiation effects group leader, AERE Harwell,

    Kirk, MA
    Metallurgist, Argonne National Laboratory, Argonne, IL

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP33808S

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