The fatigue performance of remanufactured titanium alloy blade components has garnered significant attention in recent years. The repaired titanium alloy components using the direct energy deposition (DED) method exhibit structural differences, leading to an inhomogeneous microstructure that directly impacts the service life of the remanufactured component. The work presented here aimed to investigate novel approaches for enhancing the resistance to crack propagation and to gain a deeper insight into the fatigue crack propagation characteristics of the Ti6Al4V remanufactured interface with an inhomogeneous microstructure. The research focused on analyzing the microstructure evolution and fracture properties of remanufactured components using in-situ cooling. The results indicate that in-situ cooling has the potential to decrease the anisotropy of the repaired zone (RZ) and enhance the resistance to crack propagation in the heat-affected zone (HAZ) and base metal (BM). The high cooling rate associated with the in-situ cooling can elevate the presence of high-angle grain boundaries (HAGBs) in the RZ, diminish the phase transformation between the HAZ and BM, and decrease the size of the secondary α phase. The research contributes to a deeper comprehension of fatigue crack propagation in remanufactured components and provides a pathway for the improvement of fatigue performance of remanufactured titanium alloy.

中文翻译：

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通过激光再制造过程中的原位冷却开发具有高抗疲劳裂纹扩展能力的再制造 Ti6Al4V 合金


近年来，再制造钛合金叶片部件的疲劳性能引起了人们的广泛关注。使用直接能量沉积（DED）方法修复的钛合金部件表现出结构差异，导致显微组织不均匀，直接影响再制造部件的使用寿命。本文介绍的工作旨在研究增强裂纹扩展阻力的新方法，并更深入地了解具有不均匀微观结构的 Ti6Al4V 再制造界面的疲劳裂纹扩展特性。该研究的重点是利用原位冷却分析再制造部件的微观结构演变和断裂特性。结果表明，原位冷却有可能降低修复区（RZ）的各向异性并增强热影响区（HAZ）和母材（BM）的裂纹扩展阻力。与原位冷却相关的高冷却速率可以提高 RZ 中大角度晶界 (HAGB) 的存在，减少 HAZ 和 BM 之间的相变，并减小二次 α 相的尺寸。该研究有助于更深入地理解再制造部件中的疲劳裂纹扩展，并为再制造钛合金疲劳性能的提高提供途径。