The effect of niobium element on the tensile behavior in GH3535 alloy at room temperature and 750 °C

The microstructure and tensile behavior of GH3535 and 2 wt% niobium (Nb) modified GH3535 alloys at room temperature (RT) and 750 °C were systematically investigated. It is found that Nb element is distributed in both matrix and M6C carbide, while the type and content of carbide in GH3535 alloy are barely affected by Nb element. The tensile properties at RT and 750 °C are improved by adding Nb element, which can be ascribed to the synergistic effect of the solid solution strengthening, and nano twins strengthening. Additionally, they will be improved by grain refinement at RT. The strengths of both alloys at 750 °C are lower than that of RT, which is related to the softening caused by dislocations climbing and softening of grain boundaries at high temperature.