Microstructure and mechanical properties of ZrO2 particle dispersion strengthened 16MnV steel

The dispersion strengthened 16MnV steels with 0.5 wt% and 1.2 wt% ZrO2 particles were prepared using medium frequency induction melting furnace. The ZrO2 particles mixed with iron powder were added into the 16MnV steel through cored-wire injection process. Optical metallographic microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to observe and analyze the microstructure, fracture morphology, dislocation configuration and strengthening mechanism of ZrO2 particle dispersion strengthened 16MnV steel under as-cast, normalizing and quenching states. Results showed that the strength of 16MnV steel under various states increased significantly after the addition of dispersed ZrO2 particles. Analysis indicates that the dislocation cell formed by high density dislocation around ZrO2 particles and attractive interaction between those particles are the main strengthening mechanism of dispersion strengthened 16MnV steel. The tensile test results showed that remarkable strengthening effect of ZrO2 particle on 16MnV steel has been observed. As the addition of 1.2 wt% ZrO2, the improvement of strength in ZrO2/16MnV is approximately 37.69% for as-casting, 24.2% after normalization and 29.96% after quenching, respectively. The normalized ZrO2/16MnV with 1.2 wt% ZrO2 has the highest strength of 1453 MPa.