Effect of Strain Rate on the Hot Tensile Behavior of Invar Alloy

The effect of strain rate on the hot tensile behavior of Invar alloy was studied and determination of fundamental equations by hot tensile tests over temperature range of 850- 1150 °C and at strain rates of 0.01, 0.1, 1 s-1 were carried out. The stress-strain curves and structure of sample after fracture was investigated. It was found that grain boundary sliding was the major mode of intergranular failure in the Invar alloy. In this alloy, increasing the strain rate is found to improve ductility. The experimental data of flow stress were constitutively analyzed and the apparent activation energy of deformation was estimated to be 411.5 kJ/mol.