Hot deformation behavior of spray forming LSHR alloy using constitutive equation and processing map
(School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China)
Abstract: Flow behaviors of spray forming low solvus high refractory (LSHR) alloy were investigated using hot compression tests performed on a Gleeble-3500 thermal mechanical simulator at temperatures of 1020-1150 °C and strain rates of 0.0003-1.0 s-1. The constitutive equation was established, power dissipation (η) maps and hot processing maps were plotted. The microstructure evolution and dislocation distribution of domains with different values of η in power dissipation maps were also observed. The results show that the flow stress increases with decreasing temperature and increasing strain rate. The activation energy of the spray forming LSHR alloy is 1243.86 kJ/mol. When the value of η is 0.36 at the strain of 0.5, the domain in the processing map shows characteristics of typical dynamic recrystallization (DRX) and low dislocation density. According to the microstructure evolution and processing maps, the optimum processing condition for good hot workability of spray forming LSHR alloy can be summed up as: temperature range 1110-1150 °C; strain rate range 0.01-0.3 s-1.
Key words: low solvus high refractory alloy; flow behavior; workability; power dissipation map; processing map; dynamic recrystallization