(北京科技大学 新金属材料国家重点实验室，北京100083)
摘 要: 采用Deform-3D有限元软件模拟β-γ高Nb-TiAl合金Ti-45Al-8.5Nb-0.2W-0.2B- 0.02Y(摩尔分数，%)的高温棒材挤压过程，分析挤压速度、模锥半角、挤压比以及模具圆角对合金的温度场、等效应变场、变形均匀性以及损伤因子的影响规律。结果表明：随挤压速度增加，棒材内部的温度梯度增大，变形均匀性变化不明显；随模锥半角的增加，棒材的损伤因子增加，变形的均匀性降低；随挤压比的增加，棒材的变形均匀性和损伤因子均增加；模具圆角有助于减小棒材的损伤值和抑制裂纹的产生。综合模拟结果，确定适合β-γ高Nb-TiAl合金高温挤压的工艺参数分别为：挤压速度10 mm/s、模锥半角30°、挤压比3。
关键字: β-γ高Nb-TiAl合金；高温挤压；Deform-3D模拟; 挤压速度；模锥半角；挤压比
（State Key Laboratory for Advanced Metals and Materials,
University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The hot extrusion process of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y (mole fraction, %) alloy was investigated by a Deform-3D software. The influences of extrusion speed, die half-angle, extrusion ratio and die fillet on temperature field, strain field, deformation uniformity and the damage factor were analyzed. The results demonstrate that with the increase of extrusion speed, the temperature gradient rises up and deformation uniformity has almost no change. The expanded die half-angle is detrimental to the damage factor and deformation uniformity, while the enhanced extrusion ratio promotes the improvement of the latter. The die fillet contributes to decreasing the damage of bars and restraining the cracks. According to all simulation results, extrusion speed of 10 mm/s, die half-angle of 30° and extrusion ratio of 3 are the optimal extrusion parameters of β-γ TiAl alloy containing high Nb.
Key words: β-γ TiAl alloy containing high Nb; hot extrusion; Deform-3D simulation; extrusion speed; die half-angle; extrusion ratio
