The role of retained austenite on tensile properties of steels with bainitic microstructures
The role of retained austenite on tensile properties of steels with bainitic microstructures
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DOI：
10.2320/matertrans.46.1839
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发表时间：
2005-08-01
影响因子：
1.2
通讯作者：
Caballero, FG
中科院分区：
文献类型：
--
作者：
García-Mateo, C;Caballero, FG
在高碳、富硅钢中，可以通过在低温（200-300摄氏度）下的转变获得非常精细的贝氏体显微组织。这种显微组织由细长的铁素体板组成，厚度为几十nm，在残余奥氏体的基质中。尽管强度主要由铁素体板的精细尺度（较强相）提供，但延展性主要由残余奥氏体（较软相）控制。延展性的进一步改善是通过奥氏体向马氏体的应变诱导转变（所谓的TRIP效应）来实现的。为了充分利用这一效应，奥氏体的机械稳定性，即，其在应变下转变为马氏体的能力不能太低，也不能过高。保留的奥氏体的机械稳定性的两个主要方面，形态和化学成分，已被研究，以确定这些发挥的作用，研究贝氏体钢的延展性行为。建议化学成分对这些新型高强度合金的塑性具有最强的影响。
In high-carbon, silicon-rich steels it is possible to obtain a very fine bainitic microstructure by transformation at low temperatures (200-300 degrees C). This microstructure consists of slender ferrite plates, with thicknesses of several tens of nm, in a matrix of retained austenite. Whereas strength is mainly provided by to the fine scale of the ferrite plates (stronger phase), ductility is mostly controlled by the retained austenite (softer phase). Further improvement in ductility is achieved by strain induced transformation of austenite to martensite, the so called TRIP effect. In order to take full advantage of this effect, the mechanical stability of the austenite, i.e., its capability to transform to martensite under strain, must not be too low nor excessively high.Two main aspects of the mechanical stability of the retained augtenite, morphology and chemical composition, have been studied to determine the role that these play on the ductility behaviour of the bainitic steels studied. It is suggested that the chemical composition has the strongest effect on the ductility of these new high strength alloys.