低塑性加工对定向凝固镍基合金DZ125高温氧化性能的影响

In this work, the low-plasticity burnishing (LPB) was employed to study the high temperature oxidation properties of the directionally solidified nickel-based superalloy DZ125. Microstructure analysis revealed that after the LPB process the microstructure of the surface layer changed from pristine columnar crystal to nanocrystalline, with an average grain size of about 10 nm. The surface oxide of LPB samples after high-tempe-rature oxidation at 950℃ was mainly alumina (Al₂O₃), which has better oxidation resistance than chromium oxide (Cr₂O₃). The oxide film obtained by LPB is relatively dense and uniform. Furthermore, analysis of the cross section of the specimen by EDS reveals that the LPB sample shows obvious internal-oxidation, with thicker oxide layer.