Role of twinning in the optimization of the grain boundary character distribution

Conference · Fri Jan 08 00:00:00 EST 1999

OSTI ID:6136

King, W E; Kumar, M; Schwartz, A J

The grain boundary character distribution (GBCD) is a microstructural property that describes the proportions of "special" and "random" boundaries as defined by the coincident site lattice model. Recently, there has been increased attention on determination of the GBCD and manipulation of the relative fractions in the microstructure through thermomechanical processing in order to improve material's properties like corrosion and creep resistance. Most of the "optimization" treatments reported in the literature have been performed on fee materials with relatively low stacking fault energies and have resulted in microstructures with high fractions of Σ3, Σ9, and Σ27 boundaries. It could be interpreted that annealing twins are solely required to improve the GBCD. However, in order to optimize the properties, it appears imperative that the formation of annealing twins disrupt the connectivity of the random boundary network, thus implying that Σ3ⁿ reactions and resultant triple lines are critical. Experiments to modify the GBCD of oxygen-free electronic Cu and Inconel 600 through thermomechanical processing are presented and discussed in light of observations of the deformed and recrystallized microstructures.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE Office of Defense Programs (DP)
• DOE Contract Number: W-7405-Eng-48
• OSTI ID: 6136
• Report Number(s): UCRL-JC-131664; YN0100000; 99-ERD-001; ON: DE00006136
• Resource Relation: Conference: Proceedings of the International Symposium on Advances in Twinning, Annual Meeting, San Diego, CA, February 28-March 4, 1999
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Grain Boundaries
Twinning
Optimization