Effect of Zr on behavior of compressive creep in as cast ZA27 alloy
(1. Department of Metal Materials, Sichuan University,
Chengdu 610065, China;
2. Department of Materials Science and Engineering,
Sichuan Institute of Technology, Chengdu 610039,China)
Chengdu 610065, China;
2. Department of Materials Science and Engineering,
Sichuan Institute of Technology, Chengdu 610039,China)
Abstract: The effect of Zr on the behavior of compressive creep in as cast ZA27 alloy was investigated in the temperature range of 20-160℃ and under different compressive stresses in the range of 50-137.5MPa with special apparatus. The results show that the primary compressive creep strains and steady creep rates of ZA27-Zr alloy and ZA27 alloy increase with increasing temperature and stress. However, the primary compressive creep strain and steady creep rate of the ZA27-Zr alloy are lower than that of the ZA27 alloy below 100℃, but higher at 160℃. The compressive creep behaviors in both ZA27-Zr alloy and ZA27 alloy obey an empirical equation lnt=C－nlnσ+QRT, and the exponent stress n is 3.63 for ZA27-Zr alloy and 3.46 for ZA27 alloy, respectively, the activation energy Q is 87.32kJ/mol for ZA27-Zr alloy and 81.09kJ/mol for ZA27 alloy. Different material structural constants are associated with different compressive creep behaviors in the alloy. The compressive creep rate in the alloy is controlled by the lattice diffusion of zinc and dislocation limb.
Key words: as cast ZA27 alloy; Zr; compressive creep; stress exponent; activation energy