电弧离子镀Cr-CrN-Cr-CrAlN多层膜热冲击性能研究

Study on Thermal Shock Properties of Cr-CrN-Cr-CrAlN Multilayers Prepared by Arc Ion Plating

摘要:

为进一步提升航空发动机压气机钛合金部件的服役性能，采用电弧离子镀技术在TC4钛合金表面制备抗砂粒冲蚀Cr-CrN-Cr-CrAlN多层膜。经不同温度热冲击试验后，利用扫描电镜（SEM）、X射线衍射仪（XRD）、显微硬度计、洛氏硬度计及砂粒冲蚀试验仪分析检测了多层膜的表截面形貌、硬度、结合强度和抗砂粒冲蚀性能等。结果表明：随热冲击温度的升高，多层膜的氧化程度逐级增加，当热冲击温度升至900 ℃后，多层膜已明显氧化和出现分层剥落；同样地，多层膜的显微硬度和结合强也随着热冲击温度的升高而降低，硬度由热冲击前的3658 HV降低至经900 ℃冲击后的1930 HV，结合强度则由热冲击前的HF1级降低至经900 ℃热冲击后的HF4级；在700 ℃以内，随着热冲击温度的升高多层膜的冲蚀速率上升缓慢，表明膜层的防护作用显著；而经900 ℃热冲击后，多层膜样品30和90 °攻角下的冲蚀速率由冲击前的0.28、0.65 μm?g^-1分别增大至4.05、5.00 μm?g^-1，表明膜层已失去防护作用。因此，Cr-CrN-Cr-CrAlN多层膜在700 ℃以内具有冲蚀防护效果，而900 ℃热冲击后已无抗冲蚀防护性能。

Abstract:

In order to further improve the service performance of titanium alloy components for aero-engine compressor. The sand erosion resistant Cr-CrN-Cr-CrAlN multilayers were prepared on TC4 titanium alloy by arc ion plating. After thermal shock test at different temperatures， surface cross-sectional morphology， hardness， bonding strength and sand erosion resistance of the multilayer films were analyzed by scanning electron microscopy （SEM）， X-ray diffraction （XRD）， microhardness tester， Rockwell hardness tester and sand erosion tester. The results showed that the oxidation of the multilayer films increased with the increase of thermal shock temperature. When the temperature increased to 900 ℃， the multilayer films were obviously oxidized and delaminated spalling. Similarly， the microhardness and bonding strength of the multilayer films also decreased with the increase of the thermal shock temperature. The hardness decreased from 3658 HV before thermal shock to 1930 HV after thermal shock at 900 ℃， and the bonding strength decreased from grade HF1 before thermal shock to grade HF4 after thermal shock at 900 ℃. Within 700 ℃， with the increase of thermal shock temperature， the erosion rate of multilayer films increased slowly， and the protective effect of multilayer films was significant. After thermal shock at 900 ℃， the erosion rate of multilayer films under impact at 30°and 90 ° increased from 0.28 and 0.65 μm?g^-1 to 4.05 and 5.00 μm?g^-1， which has lost its protective effect. Thus， the Cr-CrN-Cr-CrAlN multilayer films exhibit significant protect effect from sand erosion under 700 ℃， which lost its protective effect above 900 ℃.