Modifications in the grain boundary character distribution in FCC materials through thermomechanical processing
- LLNL
Recently, a body of work has emerged that indicates the potential to improve certain materials' properties through thermomechanical processing (TMP) solely by controlling grain misorientations. The grain boundary character distribution (GBCD) is defined as a microstructural property that describes the proportions of ''special'' and ''random'' boundaries with reference to the coincident site lattice model. Most of the ''optimization'' treatments reported in the literature have been performed on f.c.c. metals and alloys with medium to low stacking fault energies and have resulted in microstructures with high fractions of {Sigma}3, {Sigma}9, and {Sigma}27 boundaries, or {Sigma}3{sup n} type boundaries. It could be interpreted that only an increased incidence of annealing twinning is required to improve the GBCD. However, it also appears imperative that the formation of annealing twins disrupt the connectivity of the random boundary network, thus implying that {Sigma}3{sup n} reactions and resultant triple junctions are critical. Experiments to modify the GBCD in model materials like oxygen-free electronic Cu and Inconel 600 are presented and the efficacy of the processing routes is assessed in terms of the random boundary network and evolution of texture in the processed microstructures.
- Research Organization:
- Lawrence Livermore National Lab., CA (US)
- Sponsoring Organization:
- USDOE Office of Defense Programs (DP) (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 14660
- Report Number(s):
- UCRL-JC-133852; YN0100000; 99-ERD-001; YN0100000; 99-ERD-001
- Country of Publication:
- United States
- Language:
- English
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