Effect of annealing temperature on microstructure and mechanical properties of a high Al-low Si TRIP steel

By using optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), electron back scattered diffraction (EBSD) and tensile test, the effect of annealing temperature on microstructure and mechanical properties of a high Al-low Si TRIP steel was investigated. The results show that TRIP effect can be obtained when annealing temperature is above Ac3 due to the existence of δ-ferrite in this high Al-low Si TRIP steel. That is to say, the microstructure consisting of ferrite, bainite and retained austenite can be obtained when annealing temperature is above Ac3. Furthermore, the tensile strength and the product of strength and elongation decrease with increasing annealing temperature when annealing temperature is above Ac3.