激光再制造边部减薄Ti-6Al-4V叶片覆层与界面性能控制

Coating and Interface Performance Control of Ti-6Al-4V Blade with Thinned Edge for Laser Remanufacture

摘要:

针对强气流与烟气腐蚀易造成Ti-6Al-4V叶片减薄、再制造覆层与界面性能下降的难题，优选与Ti-6Al-4V叶片匹配度高、成形性良好的同种合金，通过元素匹配对比、能量传散规律分析、金相组织评价、再制造成形试验以及基本力学性能验证等方法，开展该类边部减薄叶片再制造覆层与界面性能控制研究。试验结果表明：覆层Ti元素含量约为80%，Al元素含量为3.9~5.5%，V元素含量为3.0~3.5%，上述主要元素含量与基体基本一致；界面处以初始等轴α相、部分片状β相以及β相晶界上析出的少量针状α′马氏体构成的网篮结构为主，部分细化和分化的β相颗粒呈弥散分布，对网篮组织晶界具有钉扎作用；覆层硬度为315.08~351.76HV0.1，为基体硬度的93%~104%，与基体匹配度良好；覆层摩擦系数在1Hz与3Hz加载频率下分别为0.22~0.35与0.32~0.62，低于TC4叶片基体。该研究在实现边部减薄Ti-6Al-4V叶片再制造良好成形的同时，验证了相关工艺及方法对覆层及界面性能调控的有效性。

Abstract:

Aiming at the problems that the Ti-6Al-4V blade with thinned edge caused by the corrosion of strong airflow and flue gas, the performance degradation of the remanufacture cladding layer and the interface. The same cladding alloy with high matching degree and good formability with Ti-6Al-4V blade substrate was chosen, through the element matching contrast, the analysis of energy dispersion law, the metallographic evaluation, the remanufacture forming experiment and the verification of basic mechanical properties, the research on the performance of remanufacture cladding layer and interface controlling was carried. The experiments results show that, the content of Ti, Al and V are respectively about 80%, 3.9~5.5% and 3.0~3.5%. The contents of the main elements above are basically consistent with the substrate. The interface is composed of initial equiaxed α phase, partially flake β phase and along with a small amount of needle-shaped α" martensite on the β phase grain boundary, all which constitute the initial basket structure. The β phase in the interface is refined and differentiated into granular, dispersing in the basket tissue. Further, the β phase at the interface is of pinning effect to the grain boundary of the staggered baskets, which is beneficial to improve the coating strength. Finally, the micro-hardness of the coating is 315.08~351.76HV0.1, which is lower than the substrate. Through the research above, not only the good forming of Ti-6Al-4V blade with edge thinning was realized, but also the related technology and methods of the cladding layer and the interface performance controlling were validated effectively.