热变形高铌TiAl合金室温塑性研究

Effect of Hot-Forging on the Room Temperature Ductility of High Nb Containing TiAl Alloy

研究了包套锻造对大尺寸高铌TiAl合金室温塑性的影响。结果表明,经过多步包套锻造后,合金室温塑性大大改善,延伸率可达2.29%。这主要归于:多步包套锻造有效地破碎了粗大的铸态组织以及在锻造过程发生了动态再结晶,这样不仅使合金平均晶粒尺寸降低,而且使合金晶粒分布均匀化,得到均匀细小的双态组织。此外,高铌TiAl合金经多步锻造后,有效消除了晶界偏析的脆性β相,从而使合金的室温塑性得到改善。

The effect of canned forging on room temperature ductility of high Nb containing TiAl alloy was studied. The results show that the RT ductility of this alloy greatly increases by the multi-step canned forging. The reasons are that the multi-step canned forging can heavily break down the coarse lamellar solidification microstructure and the dynamic recrystallization occurred during forging, so not only the mean grain size decreases but also homogeneity of the grain size increases and the β phase is successfully eliminated by the multi-step canned forging. The final microstructure after multi-step canned forging is fine and uniform and duplex, so the ductility of this alloy greatly increases.