Fractographic analysis of tensile failure in dual phase medium carbon low alloy steels

In this research work, the fracture mode of dual phase medium carbon low alloy steels which was subjected to uniaxial tensile testing, was studied. The dual phase microstructure was developed by adopting intercritical heat treatments at an isothermal temperature of 770°C for holding times of 15, 30 and 60 min. After characterising the tensile properties with the aid of a universal tensile testing machine, a scanning electron microscope (SEM-EDS) was further employed to analyse the microstructure of the developed DPS. From the results, it was observed that despite high strength being induced in the steel, the strain-to-fracture remains near 25%. The presence of dimple fractures and pull-outs, which led to the realisation of the existence of intermetallic compounds, was also obtained from the fractographs. In general, sample B-2 was soaked for 30 min and exhibits the best combination of mechanical properties.