化学热处理改善Ti-6Al-4V钛合金耐空蚀性能的研究

Improving cavitation erosion resistance of Ti-6Al-4V alloy by thermochemical treatments

利用渗氮、渗碳和碳氮共渗3种化学热处理方法对Ti-6Al-4V钛合金表面进行改性,制备出3种不同成分的硬质表面层。利用SEM、XRD和Vickers显微硬度仪分别对3种表面层的微观形貌和结构、化学组成、显微硬度进行了表征,并利用磁致伸缩振动空蚀设备研究了表面层的耐空蚀性能。结果表明通过3种化学热处理均在Ti-6Al-4V钛合金表面形成了致密的硬质陶瓷层。该硬质陶瓷层在空蚀过程中可以抑制裂纹在表面过早的形成和向基体扩展,从而延长了空蚀的孕育期和显著地改善了钛合金的耐空蚀性能。

Thermochemical treatments including gas nitriding,pack carburizing and carbonitriding were per-formed to modify the surface of Ti-6Al-4V alloy and prepare three kinds of surface layers on the surface of the alloy.Microstructure,composition and vickers microhardness were characterized using SEM,XRD and vickers microhardness test.Subsequently,cavitation erosion resistance of the surface layers was evaluated using an ul-trasonic vibratory apparatus.The results showed that a dense and hard ceramic was formed on the surface of Ti-6Al-4V alloy.The strong ceramic layers can suppress the crack initiation at the surface and prohibit the crack propagation to the basic,and resulted in the reduction of the materials damage and increase in the incubation pe-riod and cavitation erosion resistance.