High Performance Heavy Alloys by Alloying & Process Control.
Final rept. 1 May 90-15 Aug 91,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEE RING
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This report covers research conducted at RPI prior to the PIs relocation to Penn State, where the focus was on processing optimization for novel compositions fabricated by powder metallurgy. Alloys were fabricated with improved strength and hardness using alloying additions of Mo, Ta, and Re. These results were then applied to the fabrication of injection molded heavy alloys to illustrate the combination of high sintered properties within the context of net shaping without post-sintering deformation processing. Because ductility is sensitive to the processing conditions, special attention was given to identification of useful processing atmospheres. A three stage sintering atmosphere cycle was developed to optimize densification and properties, and demonstrated for times up to 10 h. For comparison, long time vacuum sintering was performed to illustrate the importance of hydrogen and dew point control for this system. Microstructural observations include a drop in the contiguity and the flattening of larger grains with long sintering times, indicative of coalescence contributions to coarsening. jg
- Metallurgy and Metallography
- Inorganic Chemistry
- Manufacturing and Industrial Engineering and Control of Production Systems