The influence of titanium element, strain rate and tested temperatures on the mechanical properties and microstructural characteristics will be investigated in this paper. These cobalt-based superalloys are tested using material testing system (MTS) at strain rates of 10−3, 10−2 and 10−1 s−1 and at temperatures of 700, 500 and 25° C, respectively. It is found that the flow stress increases with increasing strain rate and Ti, but decreases with increasing temperature. Furthermore, the strain rate sensitivity increases with increasing strain rate, but decreases with increasing temperature. The microstructural observations confirm that the mechanical response of the cobalt superalloy specimens is directly related to the effects of the titanium contents, strain rate and temperature on the evolution of the microstructure. It can be observed that the strengthening effect in cobalt-based superalloys is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature.
Strain-controlled bulge test
