Abstract
Abstract : The effect of carbon additions to tungsten and tungsten-rhenium alloys was determined by anelastic relaxation, stress relaxation and mechanical property studies. Rhenium alone, rather than a combination of rhenium and interstitials, lowers the lattice friction stress (Peierls stress) and is responsible for the ductilizing effect in tungsten. Bubbles were identified at grain boundaries of recrystallized, doped tungsten and tungsten-rhenium alloys from scanning electron microscopy studies of intergranular fracture surfaces. Auger electron spectroscopy demonstrated that these bubbles are coated with potassium which is highly localized at grain boundaries. Varying concentrations of rhenium had no noticeable effect on fracture behavior, bubble size or distribution, or potassium segregation. The bubbles dramatically raise recrystallization temperature and control grain growth texture and are, therefore, responsible for the high temperature creep properties of 'doped' tungsten and tungsten-rhenium alloys.
Published Version
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