GH4169合金气体渗氮工艺研究

Study on gas nitriding process of GH4169 alloy

利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、能谱仪(EDS)、显微硬度仪等分析手段,对GH4169合金的渗氮机理及长时间气体渗氮后渗氮层和基体组织、成分、性能进行了分析。结果表明,GH4169合金渗氮层深度和渗氮时间符合抛物线规律,长时间气体渗氮后渗层中会析出均匀细小的CrN(尺寸在纳米级)、Cr7C3相。渗氮层硬度达到1 268 HV0.05,渗氮层较脆,裂纹易沿原始γ相晶界萌生并扩展。

The mechanism of gas nitriding, microstructure, composition and properties of substrate and nitride layer of GH4169 alloy were analyzed with optical microscopy （ OM ） , scanning electron microscopy （ SEM ）, transmission electron microscopy （ TEM ）, X-ray diffractometer （XRD） ,energy disperse spectroscopy（EDS） and microhardometer after long time gas nitriding. The results show that relationship of the nitriding layer depth and nitriding time obeys parabolic law. After long time gas nitriding,fine and uniformly distributed CrN（ in the range of nano-size） and Cry C3 precipitate in the nitride layer;the microhardness reaches 1 268 HV0.05, the nitride layer is relatively brittle, and the cracks are initiated and propagated easily along the boundaries of original γ-phase.