Further understanding of metadynamic recrystallization through thermomechanical tests and EBSD characterization

Abstract

To further understand metadynamic recrystallization, various measurement techniques were performed with two materials: SUS316 austenitic steel and A5083 aluminum alloy, which were selected to represent materials with low to medium and high stacking fault energies, respectively. Microstructure characterization using electron backscatter diffraction with the grain orientation spread approach was utilized as a direct measurement technique to study metadynamic recrystallization. Additionally, indirect measurement techniques, including double-pass compression, stress relaxation, and microhardness tests, were conducted. A new approach, including its simplified version, is proposed to determine the recrystallized fraction from the stress relaxation test, which is effective even in the case of incomplete recrystallization. A comparison between various approaches for determining the recrystallized fraction shows their advantages and disadvantages. A further understanding of the metadynamic recrystallization is achieved. First, with careful setup of water cooling, unlike the conventional understanding that metadynamic recrystallization does not require an incubation time, the incubation time is approximately 1 s in both materials and can be reduced to 0 s at high temperatures in SUS316. Second, the retardation effect of external stress on recrystallization in both materials is different because on the one hand recovery competes with recrystallization, while on the other hand recovery promotes the nucleation of recrystallization.