Micromechanical Study on High-Temperature Behavior of ZrO₂ Particle-Dispersed Ni Composites

This paper aims to investigate high temperature behavior of ZrO2 particle-dispersed Ni composites. The tension-compression tests under constant stress rates as well as creep tests including stress-dip tests were performed using a high-temperature material testing set up, which consists of an electric-hydraulic fatigue testing machine, electric furnace and extensometer with a laser sensor. ZrO2 particle-dispersed Ni composites were fabricated by using the powder metallurgical methods. The results obtained from the experimental study show that ZrO2 particles remarkably strengthen the composite and there exists a reasonable correlation between the tensioncompression stress-strain relation and the creep behavior. In addition, the creep behavior has been examined based on the micromechanical concept, which takes into account the diffusional mass flow at the interface between the particles and matrix. Some numerical analysis based on this concept demonstrates that even a little amount of ZrO2 particles can effectively increase the creep resistance of the composites