2 research outputs found
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Equal Channel Angular Extrusion Progress Report for March 1998 - May 1999
Pure copper and Alloy 5083 aluminum were processed by equal channel angular extrusion (ECAE); their microstructural evolution and corresponding mechanical properties were investigated. Work also began on the possible use of ECAE to synthesize advanced materials or to consolidate metal powders or powder mixtures. The die tooling used for ECAE is described and selected microstructural and mechanical property results for ECAE-processed copper and cold-rolled (conventionally-processed) copper in the as-processed and annealed condition are compared. Results thus far show that the āpureā metal is prone to low temperature recrystallization after large strain hardeningāmore beneficial effects are expected in the dispersion-strengthened and precipitation-hardening alloys. The large range of tensile properties and grain sizes from the copper allowed a flow stress analysis to be performed. From this analysis, a new model for flow stress behavior is proposed. An evaluation of ECAE processing of material for spot welding electrodes began. Results to date include electrodes of ECAE-processed commercially pure copper (Alloy 101). Future work involving GlidcopĀ® (Al2O3 oxide dispersionstrengthened copper) and CuCrZr (Cr-Zr precipitation dispersion) materials will be required to fully investigate the benefits of ECAE for electrode life extension. Initial work on Aluminum Alloy 5083 showed that ECAE led to grain refinement as well as broke up and more uniformly dispersed the hardening precipitates. This is desirable for enhancing superplastic behavior. Study of ECAE for consolidating metal powder began. Early results with a Cu-Ag powder indicate that near 100% density was achieved with room temperature consolidation
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Iron-Phosphate Ceramics for Solidification of Mixed Low-Level Waste
A method of immobilizing mixed low-level waste is provided which uses low cost materials and has a relatively long hardening period. The method includes: forming a mixture of iron oxide powders having ratios, in mass %, of FeO: Fe{sub 2}O{sub 3}: Fe{sub 3}O{sub 4} equal to 25-40: 40-10: 35-50, or weighing a definite amount of magnitite powder. Metallurgical cinder can also be used as the source of iron oxides. A solution of the orthophosphoric acid, or a solution of the orthophosphoric acid and ferric oxide, is formed and a powder phase of low-level waste and the mixture of iron oxide powders or cinder (or magnetite powder) is also formed. The acid solution is mixed with the powder phase to form a slurry with the ratio of components (mass %) of waste: iron oxide powders or magnitite: acid solution = 30-60: 15-10: 55-30. The slurry is blended to form a homogeneous mixture which is cured at room temperature to form the final product