Optimization of annealing treatment parameters in a twin roll cast and warm rolled ZK60 alloy sheet

The microstructure of twin roll cast and warm rolled ZK60 alloy sheet was investigated using OM and TEM technique after annealing treatment at the temperature ranging from 300 °C to 400 °C. Tensile test at room temperature was performed to show the influence of annealing treatment on mechanical properties. Static recrystallization (SRX) was observed during annealing treatment of ZK60 alloy sheet at and above 300 °C. Shear bands, dislocations and twins play an important role during static recrystallization and serve as nucleation sites. Disc-shaped precipitates could be found in annealed ZK60 alloy sheet. Higher temperature annealing treatment resulted in higher density precipitates, and at this condition the dispersion strengthening particles improved the ability of resistance to softening at elevated temperature. Annealing treatment at 375 °C for 103 s can be considered to be the optimum annealing treatment, and under this condition the tensile strength, yield strength and elongation are 388 MPa, 301 MPa and 22.9%, respectively.