Randomization of Ferrite/austenite Orientation Relationship and Resultant Hardness Increment by Nitrogen Addition in Vanadium-microalloyed Low Carbon Steels Strengthened by Interphase Precipitation
Randomization of Ferrite/austenite Orientation Relationship and Resultant Hardness Increment by Nitrogen Addition in Vanadium-microalloyed Low Carbon Steels Strengthened by Interphase Precipitation
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DOI：
10.2355/isijinternational.isijint-2017-537
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发表时间：
2018-03
影响因子：
1.8
通讯作者：
Yongjie Zhang;Kunio Shinbo;T. Ohmura;Takuya Suzuki;K. Tsuzaki;G. Miyamoto;T. Furuhara
中科院分区：
文献类型：
--
作者：
Yongjie Zhang;Kunio Shinbo;T. Ohmura;Takuya Suzuki;K. Tsuzaki;G. Miyamoto;T. Furuhara
在工业应用中，铁素体钢的强化通常是通过微细析出来实现的。当合金碳化物从铁素体中析出时，通过减小颗粒间距可以获得更大的析出强化量，即在相同的体积分数下具有更高的数密度和更小的尺寸。1）特别地，通过相间析出形成的纳米合金碳化物在强化铁素体基体方面具有很大的潜力（~ 300 MPa），并伴随着对延展性和成形性的合理贡献。2 -5）当钢与强碳化物形成元素（例如铌（Nb）、钛（Ti）或钒（V））微合金化时，不同于通过过饱和基体的时效的一般沉淀，相变过程中，合金碳化物在迁移的铁素体/奥氏体（α/γ）界面上周期性形核析出，形成片状析出; 6）当α/γ界面前移时，新生成的合金碳化物留在α中，强化了α基体。结果表明，在钒微合金化的低碳钢中，通过直接冷却可以生产出高强度钢，而不需要添加氮使铁素体/奥氏体取向关系进一步随机化和由此产生的硬度增加
Strengthening of ferritic steels are usually realized by fine precipitation for industrial application. When alloy carbides are precipitated from ferrite, larger amount of precipitation strengthening can be obtained by decreasing the inter-particle spacing, i.e. with higher number density and smaller size under the same volume fraction.1) In particular, nano-sized alloy carbides formed through interphase precipitation were found to have great potential in strengthening ferritic matrix (~ 300 MPa) accompanied by reasonable contribution in ductility and thus formability.2–5) When steels are microalloyed with strong carbide-forming element, e.g. niobium (Nb), titanium (Ti) or vanadium (V), different from general precipitation by aging of supersaturated matrix, interphase precipitation occurs as the phenomenon that alloy carbides are precipitated in sheets by periodic nucleation at migrating ferrite/austenite (α/γ ) interface during transformation.6) When α/γ interface moves forward, newly formed alloy carbides will be left in α and thus strengthen α matrix. As a result, steels with high strength can be produced through direct cooling without any further Randomization of Ferrite/austenite Orientation Relationship and Resultant Hardness Increment by Nitrogen Addition in Vanadium-microalloyed Low Carbon Steels Strengthened by Interphase Precipitation