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系统研究了存在纳米尺寸碳化钒析出的铁素体和贝氏体相低碳钢的应力-应变行为。通过奥氏体/铁素体转变并结合相间析出制取组织为铁素体相的试样,通过奥氏体/贝氏体转变,随后进行时效制取贝氏体相试样。两种试样的应力-应变曲线具有几个共同特征:高屈服应力、相对低的加工硬化特性以及足够高的伸长率。根据组织参数计算了溶质原子、晶界、位错和析出物对强度的贡献,并将计算结果与试验测定的应力结果进行对比。溶质原子和晶界强化贡献可以简单地相加,而位错和析出物对强度的贡献大小应表示为两者平方和的平方根。纳米尺寸碳化物在拉伸变形早期阶段可能充当位错增生源的作用,而在变形后期则加速位错湮灭。这种增加型动态回复可能造成铁素体相和贝氏体相这两种钢都具有相当高的伸长率。
The stress-strain behavior of ferrite and bainite-phase low carbon steels with nano-sized vanadium carbide precipitated was investigated systematically. By austenite / ferrite transformation combined with the phase separation of the preparation of the microstructure of the sample ferrite phase, by austenitic / bainitic transformation, followed by aging bainite sample preparation. The stress-strain curves of the two samples have several common characteristics: high yield stress, relatively low work-hardening properties, and sufficiently high elongation. The contributions of solute atoms, grain boundaries, dislocations and precipitates to the strength were calculated according to the tissue parameters, and the calculated results were compared with those of the test. Solute atoms and grain boundary strengthening contributions can be simply summed, while the contribution of dislocations and precipitates to the magnitude of the magnitude should be expressed as the square root of the sum of the squares. Nanocrystalline carbides may act as dislocation source in the early stages of tensile deformation and accelerate dislocation annihilation in the late deformation stage. This increased dynamic response may result in relatively high elongation of both the ferritic and bainitic phases.