The relationship between microstructure and mechanical properties of Ti-Mo microalloyed steels composed of ferrite and bainite with nanometer-sized carbides and isothermally transformed at different temperatures and t...The relationship between microstructure and mechanical properties of Ti-Mo microalloyed steels composed of ferrite and bainite with nanometer-sized carbides and isothermally transformed at different temperatures and time was systematically investigated by tensile test, hardness test, and transmission electron microscopy. Ferrite formed at high temperatures exhibited both planar/curved sheet-like dispersions of interphase precipitates and random dispersion precipitates, with the interphase precipitates being the dominant morphology. In contrast, bainite formed at low temperatures exhibited only random dispersion precipitates. Furthermore, random dispersion precipitates and interphase precipitates were observed within the same ferrite grains. The mechanical properties of the ferrite specimen were superior to those of the bainite specimen. The stress-strain curves of both specimens indicated continuous yielding, high strength, and sufficient tensile elongation. The strengthening of the ferrite specimen was attributed to grain size strengthening, dislocation strengthening, and precipitation hardening, and the degree of precipitation strengthening was approximately 300 MPa.展开更多
基金The authors gratefully appreciate the financial support by National Natural Science Foundation of China (51674079)China Postdoctoral Science Foundation (2016M600211).
文摘The relationship between microstructure and mechanical properties of Ti-Mo microalloyed steels composed of ferrite and bainite with nanometer-sized carbides and isothermally transformed at different temperatures and time was systematically investigated by tensile test, hardness test, and transmission electron microscopy. Ferrite formed at high temperatures exhibited both planar/curved sheet-like dispersions of interphase precipitates and random dispersion precipitates, with the interphase precipitates being the dominant morphology. In contrast, bainite formed at low temperatures exhibited only random dispersion precipitates. Furthermore, random dispersion precipitates and interphase precipitates were observed within the same ferrite grains. The mechanical properties of the ferrite specimen were superior to those of the bainite specimen. The stress-strain curves of both specimens indicated continuous yielding, high strength, and sufficient tensile elongation. The strengthening of the ferrite specimen was attributed to grain size strengthening, dislocation strengthening, and precipitation hardening, and the degree of precipitation strengthening was approximately 300 MPa.
