热处理对锻造-增材混合制造TC4钛合金结合区组织与性能的影响

Effect of Heat Treatment on Microstructure and Properties of Forging-Additive Hybrid-Manufactured Bonding Zone of TC4 Titanium Alloy

摘要:

通过电弧熔丝增材制造技术在TC4钛合金锻造基体上沉积试样，研究了不同热处理制度对混合制造试样结合区的微观组织及性能的影响，同时对热处理后试样不同区域耐蚀性进行了研究。结果表明，随着退火温度的升高，结合区内部的α相有一定程度的粗化，并在结合区底部出现了部分等轴α相，结合区顶部的针状马氏体α′相分解。经过950 ℃/1 h/AC+600 ℃/4 h/AC固溶时效处理后，结合区力学性能的非均匀性有所改善，在具有最高的948 MPa屈服强度的同时保持了10.5%的断后伸长率，综合性能优于600和850 ℃退火处理试样。另一方面，经950 ℃/1 h/AC+600 ℃/4 h/AC固溶时效处理后，不同区域之间微观组织非均匀性的改善使混合制造TC4钛合金构件不同区域的耐蚀性差异有一定程度的减小，同时试样整体耐蚀性提高。

Abstract:

Samples were deposited on TC4 titanium alloy forged matrix by arc fuse additive manufacturing technique. The effects of different heat treatment on the microstructure and properties of the bonding zone of hybrid-manufactured samples were studied. Meanwhile, the corrosion resistance of different regions of the samples after heat treatment was also investigated. The results indicate that with the increase in annealing temperature, the α phase in the binding zone has a certain degree of coarsening, and some equiaxed α phase appear at the bottom of the bonding zone, while the acicular martensite α′ phase at the top of the bonding zone decomposes. After solution aging treatment at 950 ℃/1 h/air cooling(AC)+600 ℃/4 h/AC, the non-uniformity of mechanical properties in the bonding zone is improved, maintaining a fracture elongation of 10.5% while having the highest yield strength of 948 MPa. The comprehensive performance is better than that of samples annealed at 600 and 850 ℃. On the other hand, after 950 ℃/1 h/AC+600 ℃/4 h/AC solution aging treatment, the improvement of microstructure heterogeneity between different regions reduces the difference in corrosion resistance between different regions of hybrid-manufactured TC4 titanium alloy components to a certain extent, while the overall corrosion resistance of the sample is improved.