Ti-22Al-25Nb合金环形件成形工艺与组织性能关系

Relationship between forming process and microstructure-properties of Ti-22Al-25Nb alloy ring

研究了Ti-22Al-25Nb合金环形件的制备工艺和组织性能关系。结果表明:Ti-22Al-25Nb合金增加棒材改锻的次数可提高组织均匀性,细化晶粒,从而显著提高合金的室温塑性。对棒材在α2+B2+O三相区(970℃)和α2+B2两相区(1050℃)轧制可分别获得双态组织和板条组织的环形件。两种组织的室温抗拉强度均在1100 MPa以上,室温伸长率在6.5%以上。两种组织相比,双态组织具有更高的强度,而板条组织的塑性更好。根据试验结果,Ti-22Al-25Nb合金在生产应用时,棒材的锻造镦拔次数应不低于8次,环形件轧制应选择在α2+B2两相区(1050℃)。

The forming process of Ti-22Al-25 Nb alloy was studied and the process-microstructure-property relationships were investigated.The experimental results indicate that increasing of deformation times of Ti-22Al-25 Nb alloy bars can improve the uniformity of microstructure and refine the grain size,and to enhance ductility of bars at room temperature. The dual-microstructure and lamellar microstructure can be obtained via rolled in α2+ B2+ O region and α2+ B2 region respectively. The tensile strength of the alloy after forming process is higher than 1100 MPa and the elongation is higher than 6. 5% for both two microstructure. The dual-microstructure of the alloy has higher strength,but poor in ductility compared with lamellar microstructure. Based on the experimental results,the Ti-22Al-25 Nb alloy produced for application,the deformation times of bars should be much than 8 and the ring should be rolled in α2+ B2 region.