Microstructural Evolution of Nb–V–Mo and V Containing TRIP-assisted Steels during Thermomechanical Processing
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2017年第4期
论文作者：Erfan Abbasi William Mark Rainforth
文章页码：311 - 320
摘 要：The microstructural evolution and precipitation behaviour of Nb–V–Mo and single V containing transformation induced plasticity assisted steels were investigated during thermomechanical processing. A plane strain compression testing machine was used to simulate the thermomechanical processing. Microstructures were characterised by optical microscopy, scanning-transmission electron microscopy and microanalysis, and X-ray diffraction analysis, and Vickers hardness was obtained from the deformed specimens. The resulting microstructure of both Nb–V–Mo and V steels at room temperature primarily consisted of an acicular/bainitic ferrite, retained austenite and martensite surrounded by allotriomorphic ferrite.The TEM analysis showed that a signi?cant number of Nb（V,Mo）（C,N） precipitates were formed in the microstructure down to the ?nishing stage in Nb–V–Mo steel（i.e. 830 °C）. It was also found that the V（C,N）precipitation primarily occurred in both ferrite and deformed austenite below the ?nishing stage. The results suggested that Nb–Mo additions considerably increased the temperature stability of microalloy precipitates and controlled the microstructural evolution of austenite. However, the microalloy precipitation did not cause a signi?cant precipitation strengthening in both Nb–V–Mo and V steels at room temperature.
Erfan Abbasi，William Mark Rainforth
Department of Materials Science and Engineering, The University of Sheffield
摘 要：The microstructural evolution and precipitation behaviour of Nb–V–Mo and single V containing transformation induced plasticity assisted steels were investigated during thermomechanical processing. A plane strain compression testing machine was used to simulate the thermomechanical processing. Microstructures were characterised by optical microscopy, scanning-transmission electron microscopy and microanalysis, and X-ray diffraction analysis, and Vickers hardness was obtained from the deformed specimens. The resulting microstructure of both Nb–V–Mo and V steels at room temperature primarily consisted of an acicular/bainitic ferrite, retained austenite and martensite surrounded by allotriomorphic ferrite.The TEM analysis showed that a signi?cant number of Nb（V,Mo）（C,N） precipitates were formed in the microstructure down to the ?nishing stage in Nb–V–Mo steel（i.e. 830 °C）. It was also found that the V（C,N）precipitation primarily occurred in both ferrite and deformed austenite below the ?nishing stage. The results suggested that Nb–Mo additions considerably increased the temperature stability of microalloy precipitates and controlled the microstructural evolution of austenite. However, the microalloy precipitation did not cause a signi?cant precipitation strengthening in both Nb–V–Mo and V steels at room temperature.
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