高温退火对合金衬底上PtW薄膜应变计性能影响研究

Effect of high temperature annealing on the properties of PtW thin film strain gauge on alloy substrate

为实现航空发动机热端部件健康监测,采用磁控溅射技术在GH4169高温合金基板上制备了一种耐高温的PtW薄膜应变计。该应变计由NiCrAlY过渡层、热氧化生成TGO层、YSZ/Al_(2)O_(3)复合绝缘层和PtW功能层构成。采用SEM和EDS分析了退火前后PtW薄膜的微结构。研究结果表明,退火后PtW薄膜晶粒长大,电阻率下降,W元素含量减少且在晶界处发生富集。通过悬臂梁施加应变,研究了退火前后PtW薄膜应变计在室温~600℃下的应变敏感性能。结果表明,其应变灵敏系数均随温度升高而逐渐降低,且退火后薄膜应变计的应变灵敏系数随温度变化更为显著。该PtW薄膜应变计应变测量量程超过1400με且重复性良好,在航空航天高温部件表面应变测试领域具有广阔的应用前景。

In order to realize the health monitoring of the aero-engine hot components,a high temperature PtW thin film strain gauge was fabricated on GH4169 alloy substrate.The strain gauge consists of NiCrAlY transition layer,thermally grown oxide layer,YSZ/Al_(2)O_(3) composite insulating layer and PtW sensitive layer.The microstructure of PtW films before and after annealing was investigated.After annealing,the grain size of PtW films increased,resulting in decreasing electrical resistivity.Meanwhile,the content of W decreased and the segregation of W at the grain boundary was observed.The strain-sensitive properties of PtW thin film strain gauge from room temperature to 600℃were characterized with high temperature cantilever beam test.The results show that the gauge factor decreases with increasing temperature.Furthermore,the variation of the gauge factor becomes more severe after high temperature annealing.The upper limit of this PtW thin film strain gauge is as high as 1400μεwith good repeatability,which demonstrates great potential for surface strain measurement of hot components in aerospace field.