纳米贝氏体的热力学分析及强韧化研究

发布时间：2018-07-17 05:15

【摘要】：针对目前高碳高硅低温贝氏体(纳米结构贝氏体)相变速度缓慢的现状,采用贝氏体相变热力学理论分析主要合金元素对低温贝氏体相变驱动力的影响,设计了新型纳米结构贝氏体钢成分0.83C-2.44Si-0.43Mn-0.73Al.利用膨胀仪研究该成分贝氏体钢在不同温度下的相变整体动力学,综合使用扫描电子显微镜、X射线衍射、电子背散射衍射等方法研究热处理工艺对实验钢组织和力学性能的影响.结果表明,350℃等温转变贝氏体的抗拉强度为1401 MPa,延伸率为42.21%,强塑积可达59136 MPa·%,在室温拉伸过程中发生明显的相变诱导塑性效应;230℃等温转变组织中贝氏体铁素体片层厚度小于100 nm,抗拉强度达2169 MPa.
[Abstract]:In view of the slow transformation rate of low temperature bainite (nanostructure bainite) with high carbon and high silicon content at present, the influence of main alloy elements on the driving force of low temperature bainite transformation is analyzed by using the thermodynamic theory of bainite transformation. A new type of nanostructured bainitic steel, 0.83C-2.44Si-0.43Mn-0.73Al, was designed. The integral kinetics of phase transformation of bainitic steel was studied by means of an expander at different temperatures, and the scanning electron microscope (SEM) was used for X-ray diffraction. The effect of heat treatment on the microstructure and mechanical properties of experimental steel was studied by means of electron backscattering diffraction. The results show that the tensile strength of bainite isothermal transformation at 350C is 1401 MPA, the elongation is 42.21 and the strong plastic product is 59136 MPA. During the tensile process at room temperature, the obvious transformation induced plastic effect occurs in the bainite ferrite sheet in the isothermal transformation microstructure. The thickness of the layer is less than 100nm and the tensile strength is up to 2169 MPA.
【作者单位】：北京科技大学冶金工程研究院;北京科技大学现代交通金属材料与加工技术北京实验室;北京科技大学钢铁共性技术协同创新中心;
【基金】：国家自然科学基金资助项目(51271035)
【分类号】：TG142.1

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