EBSD Analysis of Hot Deformation Behavior of Oxide-Doped Molybdenum Alloys

Hot compression tests of Mo-1.5 wt% Al2O3/ZrO2 molybdenum alloys were carried out using the Gleeble-1500 simulator at 0.01 s(-1)-5 s(-1) strain rates and 1000-1500 degrees C deformation temperatures. The microstructural changes of the alloy at 1000-1500 degrees C were studied. The changes in the hot deformation process for the Mo-1.5 wt% Al2O3/ZrO2 molybdenum alloys were analyzed by means of EBSD. The ZrO2 particles had a greater effect on improving the thermal deformation resistance of molybdenum alloys than did the Al2O3 particles. The activation energy of the molybdenum alloy doped with ZrO2 (403.917 kJ/mol) was lower than that of the molybdenum alloy doped with Al2O3 (440.314 kJ/mol). Due to the occurrence of recrystallization, the intensity of {100} the texture first increased and, then, dropped down with increase in the temperature, while the change law of {111} texture was the opposite. Above 1200 degrees C, the higher deformation temperature made the texture more random by lowering the texture intensity. The dislocation density was sacrificed to promote recrystallization. When dynamic recrystallization occurred, the sub-grain boundaries absorbed dislocations and transformed them into high-angle grain boundaries, resulting in a decrease in dislocation density and an increase in high-angle grain boundaries at high temperatures and low strain rates. At 0.01 s(-1) strain rate, the average grain size of Mo-1.5 wt% ZrO2 alloy increased from 2.38 mu m to 4.67 mu m, and the proportion of large angle grain boundaries increased from 59.8% to 86.6%.

Automated summary

Hot compression tests were conducted on Mo-1.5 wt% Al2O3/ZrO2 molybdenum alloys at various strain rates (0.01 s(-1)-5 s(-1)) and deformation temperatures (1000-1500 degrees C). The microstructural changes of the alloy were analyzed using EBSD. The presence of ZrO2 particles had a greater impact on improving the thermal deformation resistance compared to Al2O3 particles. The activation energy of the ZrO2-doped molybdenum alloy was lower than that of the Al2O3-doped alloy.