TA15钛合金筒－锥复合曲母线构件旋压成形工艺研究

摘要

TA15钛合金作为一种高比强度结构材料具有良好的室温和高温强度、热稳定性能，广泛应用于飞机、导弹和发动机等飞行器，实现关键受力构件的减重要求。本文针对钛合金筒－锥复合曲母线构件的特点，重点开展了TA15钛合金薄壁曲母线构件热旋压成形技术的研究，采用剪切旋压预成形，强力旋压／普通旋压多道次复合旋压终成形的工艺方案，获得了成形质量较好的TA15钛合金筒－锥复合曲母线旋压件。建立了多道次曲母线构件的有限元模型，结合旋压实验解释了强旋／普旋复合成形过程中出现的典型缺陷产生机制。对热旋压过程坯料的显微组织观察分析发现，剪切旋压对显微组织具有一定程度的晶粒破碎作用，多道次强旋／普旋复合旋压成形后显微组织沿构件轴向和切向都发生伸长。经历剪切旋压和多道次强旋普旋复合旋压成形后，坯料的微观组织更加细化，且均匀性得到改善。 TA15钛合金旋压成形工件的单向拉伸实验结果表明，相对于原始坯料旋压件强度明显提高，塑性略有下降。%As a high specific strength structural material with excellent room and elevated temperature strength and thermal stability, TA15 titanium alloy is widely used in the field of aircraft, missiles and engine for the purpose of lightweight. According to the characteristic of cylinder⁃conical composite curved generatrix workpiece, the forming of thin⁃wall curved generatrix workpiece of TA15 titanium alloy was studied using hot spinning method. Shear spinning preforming was adopted, and multi⁃pass power spinning and conventional spinning were used to form the final workpiece. A multi⁃pass spinning process of curved generatrix workpiece from the plate blank was investigated through FEM simulation and process experiment. The forming process was analyzed and the mechanisms of spinning defects were revealed. The microstructural evolution results show that the grains are crushed after shear spinning and then elongated along the axial direction and circumferential direction during multi⁃pass composite power spinning and conventional spinning. The microstructure was refined and the uniformity was improved after shear spinning preforming and multi⁃pass composite spinning process. The uniaxial tensile test results of the as⁃spun workpiece showed that the strength increased significantly while the peak strain decreased slightly compared with those of the initial material.