| Abstract Scope |
This work focuses on the microstructure and properties of MAR-M247 Ni-based superalloy manufactured via directional solidification at various withdrawal rates (3.4 or 5.0 mm/min) and shell mold temperatures (1510 ˚C or 1566 ˚C) after solution heat treatment (SHT). Observations and analyses of four casting variants were carried out using thermodynamic simulations, differential scanning calorimetry (DSC), X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), X-ray spectroscopy (EDX), and tensile tests at ambient temperature. The solidus and liquidus temperatures were very similar for all variants and ranged between 1263-1264 ˚C and 1356-1359 ˚C, respectively. The presence of the γ, γ’, MC carbides, and M5B3 phases was confirmed. Microstructure differences were observed depending on the manufacturing parameters. The castings’ dendritic regions consisted of γ’ precipitates surrounded by the γ matrix, with a mean size ranging from 0.203 to 0.250 μm, depending on the casting parameters.
The authors gratefully acknowledge the funding by National Centre for Research and Development, Poland, under grant POIR.01.01.01-00-1335/20. |