QPQ工艺温度对GH901合金渗氮层组织性能的影响

Influence of QPQ treatment temperature on microstructure and properties of nitrided layer for GH901 alloy

采用QPQ盐浴复合处理技术,对GH901合金分别在600、620、650℃温度下渗氮5 h,然后均在400℃盐浴氧化30 min。利用XRD衍射仪、金相显微镜、极化测试和显微维氏硬度计和扫描电镜研究了不同渗氮温度条件下GH901合金渗层组织以及性能。结果表明,随着处理温度的升高,试样的渗层厚度呈线性增加,表面显微硬度显著增加,几乎是未处理试样表面显微硬度的3倍。然而由于Cr N的形成造成了表面渗氮层饱和固溶体中Cr含量的减少,导致GH901耐腐蚀性能下降,并且随着工艺温度的升高,耐腐蚀性能下降严重。

Nitriding treatment of GH901 was carried out at 600 ℃,630 ℃ and 650 ℃ for 5 h respectively by Quench-Polish-Quench comlex salt bath heat treatment process,followed by the same oxidation process with heating at 400 ℃ for 30 min.X-ray diffraction（ XRD）,optical microscopy（ OM）,polarization test,microhardness tester and scanning electron microscopy（ SEM） were used to study the microstructure and properties of the nitrided layer.The results indicate that the nitrided depth,microhardness and nitrogen concentration of the nitrided samples increase with the increase of nitriding temperature.However,due to the formation of Cr N and depletion of Cr in the solid solution of the nitrided layer,the corrosion resistance of treated samples get reduced.And with the increase of treatment temperature,the corrosion resistance decreases seriously.