Luhan Hao Namin Xiao Chengwu Zheng Dianzhong Li
材料科学技术（英文）
The microstructures and mechanical properties of deformation induced ferrite (DIF) in the low carbon steel Q235 under different deformation temperatures have been investigated systematically. Through deformation induced ferrite transformation (DIFT), ferrite grain can be refined to 3 μm and accounts for above 85% of the overall fraction. Yield strength of DIF (>500 MPa) is increased by up to 100% compared with the conventional low carbon steel. Comparison of microstructure and mechanical properties in the Q235 steel with DIF and tempered DIF microstructure illustrates that the strengthening mechanism of DIF microstructure is the com- bination of grain boundary strengthening and carbon supersaturated strengthening. Electron back-scattered diffraction (EBSD) analysis and high magnification scanning electron microscopy (SEM) observation denote that high-angle grain boundary among ultrafine ferrite grain and the transformation product of retain austenite membrane along ferrite boundaries are responsible for the stability of ferrite grain size during tempering
process. Transmission electron microscopy (TEM) analysis demonstrates that the transformation product of retained austenite membrane between ferrite grain boundaries is cementite.
关键词:
Low carbon steel
,
DIFT
,
Grain size
,
Mechanical properties
,
Temper resistance
Minghui CAI
,
Hua DING
,
Jiansu ZHANG
,
Long LI
金属学报(英文版)
doi:10.1016/S1006-7191(08)60076-9
Isothermal transformation (TTT) behavior of the low carbon steels with two Si contents (0.50 wt pct and 1.3 wt pct) was investigated with and without the prior deformation. The results show that Si and the prior deformation of the austenite have significant effects on the transformation of the ferrite and bainite. The addition of Si refines the ferrite grains, accelerates the polygonal ferrite transformation and the formation of M/A constituents, leading to the improvement of the strength. The ferrite grains formed under the prior deformation of the austenite become more homogeneous and refined. However, the influence of deformation on the tensile strength of both steels is dependent on the isothermal temperatures. Thermodynamic calculation indicates that Si and prior deformation reduce the incubation time of both ferrite and bainite transformation, but the effect is weakened by the decrease of the isothermal temperatures.
关键词:
Low carbon steel
,
null
,
null
,
null
,
null
Na LI
,
Zhenyu LIU
,
Yiqing QIU
,
Zhaosen LIN
,
Xianghua LIU
,
Guodong WANG
,
null
,
null
,
null
,
null
,
null
,
null
材料科学技术（英文）
In the present paper, low carbon steel strips with different phosphorus contents were produced using a twin roll strip casting process. The solidification structure was studied and its features were analyzed in detail. It was found that the strips possessed a fine microstructure compared with the mould cast steels. With increasing phosphorus content more ferrite has been formed with finer grains.
关键词:
hosphorus
,
Solidification
,
structure
,
Stri
雷淑梅
,
匡同春
,
成晓玲
,
尹诗衡
,
朱红梅
新型炭材料
doi:10.3969/j.issn.1007-8827.2007.01.013
低碳钢经浓硝酸浸蚀预处理后,调节氧乙炔火焰成碳化焰,预处理过的低碳钢基体表面火焰沉积获得纳米炭纤维涂层.采用扫描电镜、X射线衍射和显微激光拉曼光谱等先进分析手段对其形态和结构进行了表征.研究发现纳米炭纤维相互缠绕弯曲,石墨化程度高,直径为80 nm～100 nm、长度为4 μm～5 μm,形态短而粗.纳米炭纤维相互排列紧密但与基体结合力弱易从低碳钢表面脱落,浓硝酸浸蚀预处理的低碳钢表面在火焰中形成大量氧化铁颗粒,催化纳米炭纤维成核生长.
关键词:
低碳钢
,
纳米炭纤维
,
X射线衍射
,
拉曼光谱
,
氧乙炔火焰
杨王玥
,
齐俊杰
,
孙祖庆
,
杨平
金属学报
介绍了低碳钢形变强化相变的基本概念及主要特征系统的研究工作证实了变形显著地加速了低碳钢过冷奥氏体向铁素体的相变过程. 形变强化相变是一
个以形核为主导的过程. 直到相变完成以前, 形核始终存在于新相与原奥氏体相界面的高应变区. 由于几何空间与成分条件上受到一定的限制, 长大及各向异性都不太明显, 铁素体晶粒超细化. 实验工作还证实了转变动力学呈现明显的3个阶段, 它们分别与相变铁素体在原奥氏体晶界上的形核, 在铁素体/奥氏体相界前沿高畸变区的形核, 及被铁素体晶粒所包围的残存奥氏体上的相变形核等过程相对应.
关键词:
低碳钢
,
deformation enhanced
,
transformation
