Study on the thermal deformation behavior and microstructure of FGH96 heat extrusion alloy during two-pass hot deformation

• Published in: International journal of minerals, metallurgy and materials metallurgy and materials, 2019-05, Vol.26 (5), p.657-663
• Main Authors: Fang, Bin, Tian, Gao-feng, Ji, Zhen, Wang, Meng-ya, Jia, Cheng-chang, Yang, Shan-wu
• Format: Article
• Language: English
• Subjects: Boundaries; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion and Coatings; Crystallization; Deformation; Dynamic recrystallization; Dynamic response; Glass; Grain boundaries; Grain size; Materials Science; Metallic Materials; Natural Materials; Nickel base alloys; Strain; Strain rate; Stress-strain curves; Superalloys; Surfaces and Interfaces; Temperature; Thermal simulation; Thin Films; Tribology; True strain; True stress
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-019-1774-0

The change rules associated with hot deformation of FGH96 alloy were investigated by isothermal two-pass hot deformation tests in the temperature range 1050–1125°C and at strain rates ranging from 0.001 to 0.1 s −1 on a Gleeble 3500 thermo-simulation machine. The results showed that the softening degree of the alloy between passes decreases with increasing temperature and decreasing strain rates. The critical strain of the first-pass is greater than that of the second-pass. The true stress-true strain curves showed that single-peak dynamic recrystallization, multi- peak dynamic recrystallization, and dynamic response occur when the strain rate is 0.1, 0.01, and 0.001 s −1 , respectively. The alloy contains three different grain structures after hot deformation: partially recrystallized tissue, completely fine recrystallized tissue, coarse-grained grains. The small-angle grain boundaries increase with increasing temperature. Increasing strain rates cause the small-angle grain boundaries to first increase and then decrease.