Melt structure of NiCrW superalloy near liquidus studied by experiment and molecular dynamics simulation

Abstract

The effects of different isothermal temperature treatments near the liquidus on the solidification structure and melt structure of NiCrW superalloy were studied by high temperature X-ray diffraction and molecular dynamics. The results of X-ray diffraction experiments show that there is a pre-peak exists prior to the main peak at 1400 °C, which indicates that the melt is composed of clusters with medium-range order (MRO) structure. The simulation results show that the number of clusters increases as the temperature decreases, and the dominant clusters are <0 3 6 4>, <0 2 8 4>, and <0 1 10 2>. Finally, the experimental results show that the grain size distribution is relatively uniform and the degree of grain spheroidization is better at the temperature near the liquidus, which attribute to the exists of pre-peak and medium-range order in the melt.