Solid Solution Softening Rhenium Ductilizing Effect And Bubble Strengthening In Tungsten Rhenium Alloys

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.

Auger electron spectroscopy is rapidly developing into the single most powerful analytical technique in basic and applied science.for investigating the chemical and structural properties of solids. Its ex plosive growth beginning in 1967 was triggered by the development of Auger analyzers capable of de tecting one atom layer of material in a fraction of a second. Continued growth was guaranteed firstly by the commercial availability of apparatus which combined the capabilities of scanning electron mi croscopy and ion-mill depth profiling with Auger analysis, and secondly by the increasing need to know the atomistics of many processes in fundamental research and engineering applications. The expanding use of Auger analysis was accompanied by an increase in the number of publications dealing with it. Because of the developing nature of Auger spectroscopy, the articles have appeared in many different sources covering diverse disciplines, so that it is extremely difficult to discover just what has or has not been subjected to Auger analysis. In this situation, a comprehensive bibliography is obviou-sly useful to those both inside and outside the field. For those in the field, this bibliography should be a wonderful time saver for locating certain references, in researching a particular topic, or when considering various aspects of instrumentation or data analysis. This bibliography not only provides the most complete listing of references pertinent to surface Auger analysis available today, but it is also a basis for extrapolating from past trends to future expectations.