In this study, we investigated the effects of precipitates and oxide dispersoids on the high-temperature mechanical properties of oxide dispersion-strengthened (ODS) Ni-based super alloys. Two ODS Ni-based super alloy rods with different chemical compositions were fabricated by high-energy milling and hot extrusion process at 1150 °C to investigate the effects of precipitates on high-temperature mechanical properties. Further, the MA6000N alloy is an improvement over the commercial MA6000 alloy, and the KS6000 alloy has the same chemical composition as the MA6000 alloy. The phase and microstructure of Ni-based super alloys were investigated by X-ray diffraction and scanning electron microscopy. It was found that MC carbide precipitates and oxide dispersoids in the ODS Ni-based super alloys developed in this study may effectively improve high-temperature hardness and creep resistance.
Citations
A precipitation behavior of nano-oxide particle in Fe-5Y2O3 alloy powders is studied. The mechanically alloyed Fe-5Y2O3 powders are pressed at 750°C for 1h, 850°C for 1h and 1150°C for 1h, respectively. The results of Xray diffraction pattern analysis indicate that the Y2O3 diffraction peak disappear after mechanically alloying process, but Y2O3 and YFe2O4 complex oxide precipitates peak are observed in the powders pressed at 1150°C. The differential scanning calorimetry study results reveal that the formation of precipitates occur at around 1054°C. Based on the transmission electron microscopy analysis result, the oxide particles with a composition of Y-Fe-O are found in the Fe-5Y2O3 alloy powders pressed at 1150°C. It is thus conclude that the mechanically alloyed Fe-5Y2O3 powders have no precipitates and the oxide particles in the powders are formed by a high temperature heat-treatment.
Citations