Dynamic recrystallization behavior of a Mo-2.0%ZrO2 alloy during hot deformation

Abstract

The high-temperature deformation process of molybdenum alloy reinforced by 2.0%ZrO2 was tested in the temperature range of 1100–1400 °C and strain rate range of 0.005–1 s−1 in a vacuum environment, and the microstructure evolution during the high-temperature deformation process was investigated. Based on the Arrhenius model, the transient equation of the Mo-2.0%ZrO2 alloy was established, and the relationship between deformation temperature, strain rate and flow stresses was described. The flow stresses of the Mo-2.0%ZrO2 alloy were characterized by dynamic recovery and recrystallization in the deformation process. Dynamic recrystallization of the Mo-2.0%ZrO2 alloy mostly occurs at high temperatures and low strain rates. At higher strain rates (0.1–1 s−1) and low temperatures (1100–1200 °C), chain-like fine crystals and fine equiaxed grains were found, indicating that partial dynamic recrystallization occurred. At low strain (0.005 s−1) and low temperatures (1100–1200 °C), equiaxed grains were found to demonstrate continuous dynamic recrystallization. Coarse equiaxed grains were found at low strain (0.005–0.1 s−1) and high temperature (1300–1400 °C), indicating a dominance of grain growth. The Mo-2.0%ZrO2 alloy have low activation energy compared with Mo-Al2O3 alloy, which is beneficial to hot working. The Mo-2.0%ZrO2 alloy has two typical textures, 〈100〉//ND and 〈111〉//ND, after high temperature deformation. As the strain decreases, there is enough kinetic energy to reduce the basal plane deviation in TD and RD directions, and the texture of Mo-2.0%ZrO2 alloy is dominated by 〈100〉//ND.