Control of deformation and annealing process to produce incoherent Σ3 boundaries in Hastelloy C-276 alloy

Hastelloy C-276 samples were cold-rolled with their thickness reduction of 7.5% and 15%, and then annealed at 1100 degrees C for 5-60 min in solid solution. The grain boundary character distributions (GBCDs) were characterized by a technique of electron back scatter diffraction (EBSD). Results indicated that, more convoluted Sigma 3 boundaries (i.e. incoherent 13 boundaries) are generated by reasonable annealing time in low strain (7.5%) sample during strain-induced boundary migration (SIBM) processing. They can induce higher Sigma 3(n) fraction and activate more interactions between special boundaries for GBE. Instead, more coherent Sigma 3 boundaries were produced by moderate strain (15%) and annealing treatment with the occurrence of static recrystallization (SRX). The recrystallized fine grains possess fewer incoherent Sigma 3 boundaries cannot promote to get more multiple twinning for optimization of GBCD. Therefore, reasonable deformation and annealing treatment parameters lead to more incoherent Sigma 3 boundaries would play an important role in the optimization of GBE.

Automated summary

Reasonable deformation and annealing treatment parameters lead to more incoherent Sigma 3 boundaries playing an important role in the optimization of GBE.