(西北工业大学 凝固技术国家重点实验室，西安 710072)
摘 要: 通过热模拟压缩实验研究了TA15钛合金多火次等温局部锻造微观组织演化行为，并采用图形分析软件对实验所得金相照片进行分析，揭示了两相区锻造阶段的火次、近β锻的变形量、各加载工步之间以及终锻后坯料的冷却方式等变形历程对TA15钛合金等温局部近β锻微观组织演化的影响。结果表明：先变形区等轴α晶粒尺寸和含量均大于后变形区的；随着变形道次的增加，初生α晶粒的方向性逐步减弱；当总变形道次(常规锻+近β锻)达到3次时，有粗大的次生α相析出；近β锻阶段变形量达到40%时，后变形区等轴α晶粒消失，在原来等轴α晶粒存在的位置有粗大、成簇的次生α相析出；工序间和锻后水冷，较采取空冷方式时，等轴α晶粒更少、更小，次生α相更为混乱交织。研究结果可为合理制定TA15钛合金大型复杂整体构件等温条件下的多火次局部锻造成形工艺提供依据。
关键字: TA15钛合金；变形历史；局部近β锻造；微观组织
during isothermal local loading near β forging
（State Key Laboratory of Solidification Processing, Northwestern Ploytechnical University, Xi’an 710072, China）
Abstract:The microstructure of TA15 titanium alloy during isothermal local loading near β forging through isothermal compression was studied, and then the effects of forging fires, deformation of near β forging and cooling method on microstructure transform were investigated through metallograhs analysis by using image analysis software. The results show that the content of equiaxed α grains in the first deformation region is more than that in the second deformation region, and the size of equiaxed α grains is larger. The orientation of prime alpha grains decreases gradually with the increase of forging fires. When the total number of forging fires (ordinary forging + near β forging) reaches three, coarse secondary α-phase precipitates. When the deformation of near β forging reaches 40%, the equiaxed α grains are almost instead of cluster coarse secondary α-phase grains in the second deformation region. When water cool method is adopted between the forging step and after deformation, the size of equiaxed α grains is fewer and smaller, besides, the secondary α-phase grains are more disordered. The results obtained can provide a guide for isothermal local loading of large-scale complex integral components of TA15 titanium alloy.
Key words: TA15 titanium alloy; processing history; near β local forging; microstructure
