Ti-45Al-5Nb(-0.3Y)合金的连续冷却相变规律

Continuous Cooling Phase Transformation of Ti-45Al-5Nb(-0.3Y) Alloys

摘要:

冷却速度对Ti-45Al-5Nb和Ti-45Al-5Nb-0.3Y合金连续冷却相变有较大的影响。炉冷形成全层片组织，空冷下层片形成被α→γm块状反应抑制，油冷形成了极细小的层片组织，水冷主要发生了α→α2有序化转变。空冷导致了羽毛状组织消失和α2相的增加，水冷导致α2晶界的细小层片晶团尺寸较小、数量较多。Y添加对Ti-45Al-5Nb合金连续冷却相变有较小的影响。

Abstract:

Cooling rate has drastic effects on the continuous cooling transformation of Ti-45Al-5Nb and Ti-45Al-5Nb-0.3Y alloys. Furnace cooling (FC) leads to the fully lamellar microstructure. Air cooling suppresses the lamellar transformation by the α→γm reaction. Oil cooling leads to the extremely fine lamellar microstructure. At a higher cooling rate (such as water cooling), the α2 phases are predominant. By air cooling a feathery structure disappears and the α2 phase increases. By water cooling, the extremely fine lamellar regions located at initial α2 grain boundaries are smaller and increase for the Ti-45Al-5Nb-0.3Y alloy. Y addition has slight effect on the phase transformation of Ti-45Al-Nb alloy.