Determination of Free Energy of δ-Ferrite/γ-Austenite Interphase Boundary of Low Carbon Steels by In-situ Observation
Determination of Free Energy of δ-Ferrite/γ-Austenite Interphase Boundary of Low Carbon Steels by In-situ Observation
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DOI：
10.2355/isijinternational.38.794
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发表时间：
1998-08
影响因子：
1.8
通讯作者：
H. Yin;T. Emi;H. Shibata
中科院分区：
文献类型：
--
作者：
H. Yin;T. Emi;H. Shibata
利用激光共聚焦显微镜和红外成像炉对含0.017mass %磷的低碳钢中δ铁素体/γ奥氏体相变进行了原位观察。通过将样品保持在δ相和γ相以准平衡状态共存的温度下，测量了一个高能δ/δ晶界和两个非相干δ/γ晶界的三相点处的二面角。由观测到的二面角平均值，估算出低硫钢（0.007mass%）的γ/δ非共格界面自由能为0.450J/m2。一千七百公里。讨论了温度和硫含量对非相干δ/γ界面二面角和自由能的影响。
Phase transformations of δ-ferrite/γ-austenite in low carbon steels containing 0.017 mass% phosphorus are observed in-situ by using a combination of confocal scanning laser microscope with infrared image furnace. Dihedral angles at triple points of one high energy δ/δ grain boundary and two incoherent δ/γ interphase boundaries are measured by holding the sample at temperatures where δ- and γ-phases co-exist in quasi-equilibrium. From the average value of observed dihedral angles, free energy of γ/δ incoherent boundary for a steel with low sulfur content (0.007 mass%) is estimated to be 0.450 J/m2 at ca. 1700 K. The effects of temperature and sulfur content on the dihedral angle and free energy of incoherent δ/γ boundary are also discussed.