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对Ti-50Al-6Nb(at%)合金进行不同生长速度下的定向凝固实验,研究了生长速度对微观组织演变、相变路径、微观偏析和硬度值的影响。结果表明,在较低的生长速度下(≤10μm/s),凝固过程为完全β相凝固,固液界面随生长速度的增加发生平胞枝转变,最终得到α2/γ层片组织(在10μm/s时为α2/γ+B2相的组织),其中层片结构与生长方向呈45°或0°夹角。在较高速度(≥15μm/s)时,初生相为α相,固液界面为规则枝晶生长。最终组织为α2/γ层片组织,并与生长方向呈90°夹角。该成分合金的硬度值随着生长速度的增加而增加。与其它合金相比,该成分合金的硬度值较小。
Directional solidification experiments of Ti-50Al-6Nb (at%) alloy at different growth rates were carried out to investigate the effect of growth rate on microstructure evolution, phase transition path, microsegregation and hardness. The results showed that at lower growth rate (≤10μm / s), the solidification process was complete β phase solidification. The cell-cell branch was changed with the increase of growth rate at the solid-liquid interface. Finally, α2 / / s when the α2 / γ + B2 phase of the organization), which layer structure and growth direction was 45 ° or 0 ° angle. At higher velocity (≥15μm / s), the primary phase is α phase and the solid-liquid interface is regular dendrite growth. The final tissue was α2 / γ ply tissue and was at an angle of 90 ° to the growth direction. The hardness of this alloy increases with the growth rate. Compared with other alloys, the composition of the alloy hardness value is smaller.