摘要
研究了三个Fe-Ni-C合金及三个工业用铜的奥氏体强化对M_s及B_s温度的影响,M_s温度随着奥氏体屈服强度的增加而线性下降,而B_s温度和奥氏体强度之间无任何直接关系。统计了70多个铜种的TTT和CCT曲线,发现在其他合金元素含量及其他条件基本不变的前提下,奥氏体中的碳含量和贝氏体相变开始点B_s之间无任何直接关系,和马氏体相变开始点M_s之间存在着单调的反比关系,发现三个Fe-Ni-C合金的B_s温度与D_c~γ和D_(Fe)~γ成正比线性关系,求出这三个合金TTT图上鼻部温度的△G_v及D_(Fe)~γ,则它们的孕育期正比于Feder等对扩散型相变孕育期公式,说明鼻部温度时贝氏体孕育期受化学自由能差及铁原子扩散的控制。
Effect of austenite strengthening on Ms and Bs temperatures in three Fe-Ni-C alloys and three commercial steels arc studied. Ms temperature lowers linearly with the increase of the yield strength of the austenite, while Bs seems independent of the austenite strengthening. Statistics of TTT and CCT diagrams of more than seventy steels shows that,as alloying element contents and austenitization are nearly identical, Bs temperatures of various steels arc independent of the carbon contents in austenite, but Ms decrease monotonically with the increase of the earbon contents. By plotting Bs temperature of the three Fe-Ni-C alloys versus D~γ(C) and D~γ(Fe), a linear relation is obtained. The ΔGv and D~γ(Fe) of the alloys were calculated at the nose temperatures in TTT diagrams, and the incubation periods are directly proportional to the values deduced from Feder's equation for diffusional transformations, implying that the incubation period at the nose temperature of bainitic transformationis is governed by the change in free energy and the diffusion of iron atoms in austenite.
出处
《上海金属》
CAS
1990年第4期3-10,共8页
Shanghai Metals
