High temperature simulation study of the mechanical properties of Y_2O_3/Ni-20 wt% Cr matrix composites prepared by mechanical alloying

摘要

Ni-20 wt% Cr matrix composites reinforced by Y_2O_3 particles (Y_2O_3/Ni-Cr composites) have been separately prepared by mechanical alloying and powder metallurgy. The effects of mechanical alloying on the mechanical properties of the composites at room temperature and high temperature have been studied. It found that nickel and chromium powders become a whole solid solution powder after mechanical alloying for 20 h. The density, hardness and ultimate tensile strength of the composites prepared by mechanical alloying is higher than those prepared by powder metallurgy. High temperature simulation for mechanical properties was carried out based on Larson-Miller function. The simulation results show that the Vickers hardness of the tested materials is approximately proportional to the heat treatment parameter P, which indicates that Larson-Miller function is applicable for the life-span design of Ni-based composites. After heat treatment at high temperature, the 0.8%Y_2O_3/Ni-Cr composite prepared by mechanical alloying still maintains good mechanical properties.