将C含量(质量分数)分别为0.05%和0.4%的Fe-C-Mn-Si钢进行等温处理得到贝氏体组织,采用EBSD技术对奥氏体共格孪晶界上形成的贝氏体铁素体变体进行分析.结果表明,2种钢中的贝氏体铁素体与母相奥氏体均成近似K-S取向关系.奥氏体孪晶界两侧...将C含量(质量分数)分别为0.05%和0.4%的Fe-C-Mn-Si钢进行等温处理得到贝氏体组织,采用EBSD技术对奥氏体共格孪晶界上形成的贝氏体铁素体变体进行分析.结果表明,2种钢中的贝氏体铁素体与母相奥氏体均成近似K-S取向关系.奥氏体孪晶界两侧形成取向相同的变体对.此变体对形成后,孪晶界基本不再显现.晶体学分析表明,共格孪晶界两侧可能出现的变体对最多不超过3组,且这3组变体对的惯习面均与孪晶界平行,因此,贝氏体铁素体变体都将沿孪晶界生长.含C量为0.05%的Fe-C-Mn-Si钢中奥氏体孪晶界上只观察到一组贝氏体铁素体变体对的形成,这是因为C含量较低,贝氏体铁素体生长速度较快,消除了其它变体对的形核机会,先形核的变体对一旦形核就迅速覆盖整个孪晶面.而在含C量为0.4%的Fe C Mn-Si钢中,由于C含量较高,贝氏体铁素体生长速度较慢,3组变体对均有机会形核,因此,在孪晶界上可以观察到这3组变体对同时出现.展开更多
The thermodynamic database of the Fe C Mn-Si system has been developed in the framework of the CALPHAD approach. The sub-ternary systems have been carefully evaluated and revised based on available experimental data. ...The thermodynamic database of the Fe C Mn-Si system has been developed in the framework of the CALPHAD approach. The sub-ternary systems have been carefully evaluated and revised based on available experimental data. A satisfactory description of the liquid phase in the Fe C-Si system has been obtained. The C Mn Si system was assessed treating the liquid phase as a substitutional solution. Phase equilibria in the C- Mn-Si system, especially those involving the liquid phase, can be well described. Based on the extrapolation of the experimental data in the quaternary system, the Fe Mn Si system has been modified to agree well with experimental data at high temperatures. The comparison between the calculated and measured phase transformation tempera tures confirms the reliability of the present quaternary database. Additionally, the solidification process of Fe-0. 16C-1. 5Mn-1. 5Si （wt. %） alloy was simulated by using the thermodynamic database developed.展开更多
Warm deformation tests were performed using a kind of tubby heater. The microstructures and mechanical properties of an Fe-C-Mn-Si multiphase steel resulting from different warm deformation temperatures were investiga...Warm deformation tests were performed using a kind of tubby heater. The microstructures and mechanical properties of an Fe-C-Mn-Si multiphase steel resulting from different warm deformation temperatures were investiga- ted by using LOM （light optical microscopy）, SEM and XRD. The results indicated that the microstructure contai- ning polygonal ferrite, granular bainite and a significant amount of the stable retained austenite can be obtained through hot deformation and subsequent austempering. Warm deformation temperature affects the mechanical prop- erties of the hot rolled TRIP steels. Ultimate tensile strength balance reached maximum （881 MPa） when the speci- men was deformed at 250 ~C, and the total elongation and strength-ductility reached maximum （38% and 28 614 MPa ~ ~, respectively） at deforming temperature of 100 ~C. Martensite could nucleate when austenite was deformed above M~, because mechanical driving force compensates the decrease of chemical driving force. The TRIP effect occurs in the Fe-C-Mn-Si multiphase steel at deforming temperature ranging from 15 to 350 ~C. The results of the effects of warm deformation on the mechanical properties of the Fe-C-Mn-Si multiphase steel can provide theoretical basis for the ap- plications and the warm working of the hot rolled TRIP sheet steels in industrial manufacturing.展开更多
通过弯曲法测量、热循环训练、扫描电镜、X射线衍射等方法,研究了复合稀土对Fe Mn Si Ni C合金形状记忆效应的影响。研究结果表明,Fe Mn Si Ni C合金中加入复合稀土,能够明显细化合金的金相组织,显著提高合金的形状记忆效应,并使合金表...通过弯曲法测量、热循环训练、扫描电镜、X射线衍射等方法,研究了复合稀土对Fe Mn Si Ni C合金形状记忆效应的影响。研究结果表明,Fe Mn Si Ni C合金中加入复合稀土,能够明显细化合金的金相组织,显著提高合金的形状记忆效应,并使合金表现出微弱的双程记忆效应。试验结果还表明,第一种训练途径以及加入微量复合稀土是降低应力诱发ε马氏体稳定化行之有效的方法,X射线衍射结果表明,该训练方法有助于提高合金中ε→γ转变的ε逆转变率,对提高合金的记忆性能起积极的作用。展开更多
文摘将C含量(质量分数)分别为0.05%和0.4%的Fe-C-Mn-Si钢进行等温处理得到贝氏体组织,采用EBSD技术对奥氏体共格孪晶界上形成的贝氏体铁素体变体进行分析.结果表明,2种钢中的贝氏体铁素体与母相奥氏体均成近似K-S取向关系.奥氏体孪晶界两侧形成取向相同的变体对.此变体对形成后,孪晶界基本不再显现.晶体学分析表明,共格孪晶界两侧可能出现的变体对最多不超过3组,且这3组变体对的惯习面均与孪晶界平行,因此,贝氏体铁素体变体都将沿孪晶界生长.含C量为0.05%的Fe-C-Mn-Si钢中奥氏体孪晶界上只观察到一组贝氏体铁素体变体对的形成,这是因为C含量较低,贝氏体铁素体生长速度较快,消除了其它变体对的形核机会,先形核的变体对一旦形核就迅速覆盖整个孪晶面.而在含C量为0.4%的Fe C Mn-Si钢中,由于C含量较高,贝氏体铁素体生长速度较慢,3组变体对均有机会形核,因此,在孪晶界上可以观察到这3组变体对同时出现.
基金the financial support from the Chinese National Key Project of Science and Technology (Grant No. 2012ZX06004-012)the support from the Chinese Scholarship Council (CSC)the support from the Shanghai Municipal Science and Technology Commission (Grant No. 15DZ2260300,15DZ2260301)
文摘The thermodynamic database of the Fe C Mn-Si system has been developed in the framework of the CALPHAD approach. The sub-ternary systems have been carefully evaluated and revised based on available experimental data. A satisfactory description of the liquid phase in the Fe C-Si system has been obtained. The C Mn Si system was assessed treating the liquid phase as a substitutional solution. Phase equilibria in the C- Mn-Si system, especially those involving the liquid phase, can be well described. Based on the extrapolation of the experimental data in the quaternary system, the Fe Mn Si system has been modified to agree well with experimental data at high temperatures. The comparison between the calculated and measured phase transformation tempera tures confirms the reliability of the present quaternary database. Additionally, the solidification process of Fe-0. 16C-1. 5Mn-1. 5Si （wt. %） alloy was simulated by using the thermodynamic database developed.
基金Sponsored by National Natural Science Foundation of China (50334010)
文摘Warm deformation tests were performed using a kind of tubby heater. The microstructures and mechanical properties of an Fe-C-Mn-Si multiphase steel resulting from different warm deformation temperatures were investiga- ted by using LOM （light optical microscopy）, SEM and XRD. The results indicated that the microstructure contai- ning polygonal ferrite, granular bainite and a significant amount of the stable retained austenite can be obtained through hot deformation and subsequent austempering. Warm deformation temperature affects the mechanical prop- erties of the hot rolled TRIP steels. Ultimate tensile strength balance reached maximum （881 MPa） when the speci- men was deformed at 250 ~C, and the total elongation and strength-ductility reached maximum （38% and 28 614 MPa ~ ~, respectively） at deforming temperature of 100 ~C. Martensite could nucleate when austenite was deformed above M~, because mechanical driving force compensates the decrease of chemical driving force. The TRIP effect occurs in the Fe-C-Mn-Si multiphase steel at deforming temperature ranging from 15 to 350 ~C. The results of the effects of warm deformation on the mechanical properties of the Fe-C-Mn-Si multiphase steel can provide theoretical basis for the ap- plications and the warm working of the hot rolled TRIP sheet steels in industrial manufacturing.
文摘通过弯曲法测量、热循环训练、扫描电镜、X射线衍射等方法,研究了复合稀土对Fe Mn Si Ni C合金形状记忆效应的影响。研究结果表明,Fe Mn Si Ni C合金中加入复合稀土,能够明显细化合金的金相组织,显著提高合金的形状记忆效应,并使合金表现出微弱的双程记忆效应。试验结果还表明,第一种训练途径以及加入微量复合稀土是降低应力诱发ε马氏体稳定化行之有效的方法,X射线衍射结果表明,该训练方法有助于提高合金中ε→γ转变的ε逆转变率,对提高合金的记忆性能起积极的作用。
