2.3 Uniaxial Tensile Test of MTP and SSFS specimens
Prior to high temperature LCF testing, uniaxial tensile test had been performed on MTP-3 and compared with SSFS testing results at 20 °C and 600 °C, respectively, in order to demonstrate the capability of the testing technique. The miniature uniaxial tensile tests were conducted using the testing rig as introduced in Section 2.2 (see Fig.2c). The applied displacement-rate for the MTP-3 specimen was under a constant of strain-rate of 0.01%s-1 during the tensile testing, which is consistent with the loading process of the SSFS tensile testing1. The applied torque on both screw bolts were keep the same with a value of 0.5Nm to avoid any torsions during testing and provide enough clamping force. Noted that the displacements were measured at the ends of the fillet radius regions since it is difficult to accommodate the extensometers into the very limited region. As can be seen from the testing results in terms of engineering stress-strain curves estimated from the initial cross-section area and displacement shown in Fig.3, the tensile responses from MTP-3 specimen follow the typical temperature-dependent stress-strain behaviors, for example, higher ultimate tensile response and lower ductility at 20 °C compared with these at 600 °C. More importantly, almost identical trend can be achieved, which indicates the possibility to make the comparisons of high temperature LCF and CF tests between MTP and SSFS specimens.