无碳化物贝氏体钢变形时微结构演变、成分和应变配分规律研究

项目名称： 无碳化物贝氏体钢变形时微结构演变、成分和应变配分规律研究

项目编号： No.51471146

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 张福成

作者单位： 燕山大学

项目金额： 85万元

中文摘要： 无碳化物贝氏体钢是一类以贝氏体铁素体相为主残余奥氏体相为辅的双相钢，已被广泛的应用于制造汽车钢板、铁路轨道、车轮曲轴、齿轮和轴承等，成为新一代先进钢铁材料的代表之一。众所周知，贝氏体相变过程因成分配分使碳和一些合金元素在贝氏体铁素体和残余奥氏体两相中含量不同。然而，在变形过程中，两相中的化学成分如何再配分？两相的微结构如何变化？且应变在两相中配分规律如何？这种因变形造成的微结构变化以及成分配分和应变配分是如何相互作用的？其对钢的宏观力学行为，特别是循环变行行为影响规律如何？这些材料科学问题尚不清楚。本项目是以中碳无碳化物贝氏体钢为研究对象，在上、下贝氏体转变温度区间分别对其进行等温相变处理，通过拉伸和循环变形，利用三维原子探针、纳米压痕、EBSD、共聚焦显微镜以及TEM、XRD等研究手段，解答以上疑问，弄清高强度抗疲劳无碳化物贝氏体钢的化学成分和微结构调控机制。

中文关键词： 无碳化物贝氏体钢；变形；配分；微观结构

英文摘要： Carbide-free bainitic steel, is kind of dual phase steel dominated by bainitic ferrite and supplemented by retained austenite. It has attracted extensive interest and attention as one of the representative of a new generation advanced material, which has been widely used in manufacturing automobile steel plate, railway track, wheel, shaft, gear and bearing. As well known, there exist different contents of carbon and some substitutional elements in bainite ferrite and retained austenite phase induced by the chemical composition partitioning during bainitic transformation. However, how do the chemical compositions redistribute in the two phases during the deformation? What is the evolution of microstructures? What are the strain partitioning pattern in the two phases? How do the afore-mentioned behaviors influence the macro-mechanical properties especially for the cyclic deformation behaviors? These materials science problems are not clear. Hence, to answer these questions, understand the controlling mechanism of the chemical composition and the microstructure of the carbide-free bainitic steels with high strength and good fatigue performance, a medium carbon carbide-free bainitic steel is studied and subjected to isothermal transformation at upper and lower bainitic transformation temperature region in this project. The tensile and cyclic deformation behaviors of the steel are analyzed through three-dimensional atom probe, nano-indentation, EBSD, confocal microscope, TEM, SEM and XRD.

英文关键词： Carbide-free Bainitic Steel;Deformation;partitioning