Microstructural Evolution of Nb-V-Mo and V Containing TRIP-assisted Steels during Thermomechanical Processing

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2017,（4）
• 页码范围: 311-320
• 页数: 10页
• 语种: 英文

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 significant number of Nb(V,Mo)(C,N) precipitates were formed in the microstructure down to the finishing stage in Nb-V-Mo steel (i.e.830 ℃).it was also found that the V(C,N) precipitation primarily occurred in both ferrite and deformed austenite below the finishing 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 significant precipitation strengthening in both Nb-V-Mo and V steels at room temperature.