Hot deformation behavior of KFC copper alloy during compression at elevated temperatures
(1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. School of Materials Science and Engineering, University of Science and Technology Beijing,Beijing 100083, China)
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. School of Materials Science and Engineering, University of Science and Technology Beijing,Beijing 100083, China)
Abstract: The hot deformation behavior of a KFC copper alloy was studied by compression deformation tests on Gleeble 1500 machine at strain rates ranging between 0.01−10 s−1 and deformation temperature of 650−850 ℃, and associated structural changes were studied by observations of metallography and TEM. The results show that the true stress–true strain curves for a KFC copper alloy are characterized by multiple peaks or a single peak flow, and tend to a steady state at high strains. The peak stress can be represented by a Zener-Hollomon parameter in the hyperbolic-sine-type equation with the hot deformation activation energy Q of 289 kJ/mol. The dynamic recrystallization(DRX) occurs by bulging out of part serrated grain-boundary, and the dynamic recrystallization grain size is dependent sensitively on deformation temperature T and strain rate , also a function of Z. The dynamic spherical Fe-rich precipitates and successive dynamic particles coarsening has been assumed to be responsible for flow softening at high strains, and this is more effective when samples deformed at low temperatures and higher strain rates.
Key words: KFC copper alloy; hot compression deformation; flow softening; dynamic recrystallization; dynamic precipitation