Microstructure – Properties Relationships in Carbide-free Bainitic Steels
Microstructure – Properties Relationships in Carbide-free Bainitic Steels
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DOI：
10.2355/isijinternational.51.1724
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发表时间：
2011-09
影响因子：
1.8
通讯作者：
J. Hell;M. Dehmas;S. Allain;J. M. Prado;A. Hazotte;J. Chateau
中科院分区：
文献类型：
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作者：
J. Hell;M. Dehmas;S. Allain;J. M. Prado;A. Hazotte;J. Chateau
通过特殊的合金设计和等温淬火工艺，制备了两种不同组织的无碳化物贝氏体钢。通过EBSD分析和原位高能同步辐射衍射进行显微组织表征，以评估残余奥氏体中的相分数和碳含量以及显微组织。这些显微组织特征与拉伸性能相关。这两种钢都表现出高强度（1250 MPa以上）、良好的延展性（均匀延伸率高达14%）和高断裂应变（断面收缩率高达46%）之间的优异折衷。MA块（残余奥氏体块在室温下最终冷却期间部分转化为新鲜马氏体）的体积分数是强烈影响加工硬化的关键相关参数，其以高应变下的损伤过程为代价。
We elaborated two carbide-free bainitic steels with different microstructures through specific alloy design and austempering process. Microstructural characterizations were performed by means of EBSD analysis and in-situ high energy synchrotron diffraction in order to evaluate the phase fractions and the carbon content in the retained austenite, as well as the microtextures. These microstructural features were correlated to the tensile properties. Both steels exhibited an excellent compromise between high strength (above 1250 MPa), good ductility (uniform elongation up to 14%) and high fracture strain (reduction of area up to 46%). The volume fraction of MA blocks (blocks of retained austenite partially transformed into fresh martensite during the final cooling at room temperature) was a key relevant parameter that strongly influenced the work-hardening at the expense of the damaging processes at high strain.