Copper precipitation during continuous cooling and isothermal aging of A710-type steels
- Colorado School of Mines, Golden, CO (United States)
Precipitation in copper-containing A710 (also referred to as HSLA-80) and modified-A710 steels was investigated by transmission electron microscopy. Isothermal aging of as-quenched specimens at 675 C produced {var_epsilon}-copper precipitates located primarily at {alpha}-iron matrix dislocations. The precipitates exhibited multiple variants of an orientation relationship (OR) consistent with that reported by Kurdjumov and Sachs, fine fault formation, and associated streaking in electron diffraction patterns. For reaustenitized and continuously cooled specimens, the primary precipitation event was associated with interphase precipitation of copper at ferrite/austenite interfaces. Interphase precipitates frequently displayed ORs other than that reported by Kurdjumov and Sachs, although a unique crystallographic variant was observed within any one region of interphase precipitation, faults were observed infrequently, and streaking was not observed in diffraction patterns. At high temperatures during cooling, precipitate-free ferrite formed, whereas at lower temperatures, nucleation of copper precipitates occurred at ferrite/austenite interfaces for crystals of polygonal ferrite and Widmanstaetten ferrite. This latter feature precludes the formation of Widmanstaetten ferrite via a displacive mechanism. Interphase precipitation was not observed for granular ferrite or acicular ferrite. Less-common precipitation events during continuous cooling included the formation of AlN and CuS.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 264076
- Report Number(s):
- CONF-941016-; ISSN 0360-2133; TRN: IM9633%%10
- Journal Information:
- Metallurgical Transactions, A, Vol. 27, Issue 6; Conference: Materials week `94, Rosemont, IL (United States), 3-7 Oct 1994; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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