Microstructure of Ti2AlNb-based Alloy Processed by Multi-directional Forging in (B2+O) Phase Region [Ti2AlNb基合金(B2+O)相区多向锻造微观组织]

作者：Xue K.; Hu Y.; Shi Y.; Ji X.; Gan G.; Li P.^*

来源：Rare Metal Materials and Engineering, 2019, 48(8): 2556-2561.

• (B2+O) phase region
• Microstructure
• Multi-directional forging
• Ti2AlNb-based alloy

Multi-directional forging (MDF) process with different cycles was conducted on the Ti2AlNb-based alloy under the temperature of 800 °C in the (B2+O) phase region followed by water cooling. The microstructure was characterized by electron backscatter diffraction (EBSD) and X-ray diffraction (XRD), and the effect of MDF process cycles on microstructure evolution of Ti2AlNb-based alloy was analyzed. The results show that the microstructure is significantly refined to submicrometer, the misorientation of grain boundaries has the transformation from low angle to high angle and the equiaxed ultrafine grains with high angle boundaries are obtained after MDF processing. The grain size decreases rapidly after one cycle of MDF and the value keeps nearly constant with the increasing number of MDF cycles. After deformation, the major phases of the alloy are B2+O, as well as some residual α2 phase. The content of α2 phase decreases while the O phase increases compared to the initial sample. In addition, the microstrain and dislocation density increase significantly after deformation. Because of dynamic recovery, the microstrain saturates to a stability level with the number of cycles increasing, while the dislocation density experiences a slight decrease.

• 单位
  合肥工业大学