Influence of temperature and strain rate on hot deformation behavior of Zr50Ti50 alloy in single β field
(1. State Key Laboratory of Metastable Materials Science and Technology,
Yanshan University, Qinhuangdao 066004, China;
2. College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, China)
Yanshan University, Qinhuangdao 066004, China;
2. College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, China)
Abstract: The deformation behavior and microstructure of the Zr50Ti50 alloy in β phase field were investigated by isothermal compression tests at temperatures ranging from 700 to 850 °C and strain rates ranging from 0.001 to 1 s-1. The flow curves exhibited typical flow softening. The initial discontinuous yielding behavior was observed at higher strain rates, which was not found in other traditional Zr alloys. The apparent deformation activation energy was calculated to be 103 kJ/mol and constitutive equation describing the flow stress as a function of the strain rate and deformation temperature was proposed. The analysis indicated that the hot deformation mechanism was mainly dominated by dynamic recovery. However, dynamic recrystallization was delayed by dynamic recovery. Thereafter, the processing map was calculated to evaluate the efficiency of the forging process at the temperatures and strain rates investigated and to optimize processing parameters of hot deformation. The optimum processing parameters were found to be 830-850 °C and 0.56-1 s-1 for hot the deformation of Zr50Ti50 alloy in the β phase region.
Key words: Zr alloy; hot deformation; apparent activation energy; microstructure; processing map