| Autor: |
Vander Sande, J., Coke, J., Wulff, J. |
| Zdroj: |
Metallurgical and Materials Transactions A; February 1976, Vol. 7 Issue: 2 p389-397, 9p |
| Abstrakt: |
Abstract: Microstructures produced in the Co-Cr-Mo-C alloy H.S.21 were observed by transmission electron microscopy in cast specimens following solutionizing at 1230C and aging at 650C and in low-carbon wrought specimens following solutionizing and aging at 650C and 750C. In all cases, aging was found to promote the formation of fcc stacking faults and to cause an initial martensitic transformation from the fcc phase to a heavily faulted hep structure. Precipitate formation was observed in hcp areas of the cast material after 20 h at 650C and in hcp areas of wrought material after 20 h at 750C. Prolonged aging at 750C produced a transformation in the hcp structure of wrought specimens, with a relatively fault-free structure replacing the heavily faulted martensitic form. Interruption of fcc slip by both fcc stacking faults and bands of hcp phase was found to be the principal strengthening mechanism activated by aging. Precipitate formation in the hcp plays an increasingly significant role as aging time is increased. This microstructural information is used to explain the observed tensile properties of these alloys after the heat treatments mentioned. |
| Databáze: |
Supplemental Index |
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