Investigating the impression creep behavior of AZ31B alloy in a wide range of temperature and stress
摘要
This research aims to explore the creep behavior of the AZ31B alloy under various temperature and stress conditions using the impression technique. The experimental studies were carried out at temperatures ranging from 150 °C to 250 °C and stress levels ranging from 121 to 401 MPa. The results showed that the stress exponent and activation energy of this alloy varied depending on the test conditions, resulting in different creep mechanisms. The stress exponents obtained at high-stress values were 7.2, 4.44, 9.59, and 11.35 at 150, 175, 200, and 250 °C, respectively. In low-stress regimes, the values were 1.12, 3.25, 4.77, and 4.91, respectively. Results highlighted that at lower stress levels, grain boundary diffusion, dislocation viscous glide, and dislocation climb were the dominant creep mechanisms, while at high stress levels, dislocation climb and a combination of dislocation climb, glide, and cross-slip mechanisms governed the material’s deformation behavior. The activation energy was determined to be 87.61 kJ/mol at low-stress conditions, indicating grain boundary diffusion and pipe diffusion as the rate-controlling mechanisms. Under high-stress conditions, it reached 103.7 kJ/mol, suggesting pipe diffusion or Mg lattice self-diffusion. The upper-bound analysis results were also used to establish the correlation between creep properties obtained from impression (