Application of equal channel angular extrusion to consolidate aluminum 6061 powder /
alloy, Al 6061, was investigated to characterize
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: |
| Summary: | alloy, Al 6061, was investigated to characterize compacts processed by Equal Channel Angular Extrusion. ECAE is a new material processing method whereby high levels of strain can be applied to bulk material. Full versification and excellent bonding of particles can be achieved in powder compacts. The main objective of this investigation is to characterize the effects of temperature, number of passes and route on aluminum 6061 powder consolidated through ECAE. Copper 101 containers filled with loose powder (62% of theoretical density) were extruded 1, 2 or 4 times following two different extrusion routes. Extrusion temperatures included 77[]K, 293[]K, 423[]K and 623[]K. Microstructure analysis, hardness and density measurements were performed. Dog bone specimens were prepared to determine tensile properties of the compacts before and after a post extrusion heat treatment. SEM analysis was conducted on some of the fractured tensile specimens. Above 98% of theoretical density is obtained after one extrusion pass for all temperatures examined and 111 consolidation is attained after two passes. Variations in processing temperature and route did not have a significant effect in the versification of the powder. Tensile testing reveals that extrusions at 77[]K and 295[] produce brittle as-extruded compacts even though the porosity is of less than 2%. At 423[]K, the strength of the alloy is enhanced with increasing number of passes. Extrusions at 423[]K following route A to develop lamellar microstructures and without heat treatment after four passes rendered an increase of 23% in tensile strength and 24% in yield strength over the properties of wrought material. Route C to develop equipped microstructural produces no increase in tensile strength and only 6% in yield strength respectively. The application of a standard solution heat treatment, quenching and aging treatment augmented the strength of the compacts, but decreased the percentage elongation and percentage of reduction in area. The tensile strength of heat treated compacts falls within the range of 40 and 43 Ksi in all cases. The results demonstrate the benefits of consolidating Al 6061 powder through ECAE. |
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| Item Description: | Vita. "Major subject: Mechanical Engineering". |
| Physical Description: | xiii, 161 leaves : illustrations ; 28 cm. Issued also on microfiche from Lange Micrographics. |
| Bibliography: | Includes bibliographical references (leaves 126-129). |