单晶高温合金DD6真空热处理表面完整性研究

Study of the Surface Integrity of the Crystal High-temperature Alloys DD6 in Vacuum Heat Treatment

采用扫描电子显微镜的能谱分析仪对单晶高温合金(DD6)不同真空热处理状态试样表面的氧化、合金元素的贫化及表面的污染进行了测试。结果表明:1315℃真空加热4h,试样表面的氧化均很微弱,高(~5×10-3Pa)、中(~5×10-2Pa)真空度下,Al,Cr,Ni,W,Co,Ta,Re等元素的含量均显著减少,深度可达7~12μm,而低真空度(~1×10-2Pa)下元素减少不明显。真空充氩气保护下,除充氩气压力为1~10Pa外,其它各充氩气压力下均有氧化和Cr,Ni,Co,W,Ta,Re等元素的贫化现象,而且存在Al元素含量增加现象。充氩气压力为1~10 Pa和高、中真空度下,试样表面的Mo,B含量显著增加,这是真空炉加热体与隔热体蒸发的Mo,B沉积在试样表面的结果。加热体为Mo带的真空炉在高温、高真空度下使用时会成为Mo,B元素的污染源。

The surface oxidation,the poverty of alloying elements and surface pollution of DD6 single crystal alloy in different vacuum heat treatment state were investigated by means of SEM and EDAX.The results show that the surface oxidation of the sample at 1315℃ vacuum heating 4h,are very weak,under high vacuum(~ 5×10-3Pa)and medium vacuum(~ 5×10-2Pa),content of Al,Cr,Ni,W,Co,Ta,Re and other elements were decreased in depth up to 7-12μm,the reduction of element content was not obvious under low vacuum(~ 1×10-2Pa);that when the vacuum and the protection of filling argon,with the exception of filling argon pressure for 1-10Pa,under the other the pressure of argon,the surface of the sample have oxidation phenomenon and the phenomenon of poverty of Cr,Ni,Co,W,Ta,Re and other elements,but Al elements of the sample surface were increased;that under the pressure of argon for 1-10 Pa and in the high and medium vacuum,the surface of Mo,B were markedly increased,which is duty to Mo,B elements of evaporation from vacuum furnace heating body were deposited on the surface of the sample.