Beijing Laboratory of Metallic Materials and Processing for Modern Transportation

Beijing, China

Beijing Laboratory of Metallic Materials and Processing for Modern Transportation

Beijing, China

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Ding R.,University of Science and Technology Beijing | Tang D.,University of Science and Technology Beijing | Tang D.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Zhao A.,University of Science and Technology Beijing | Zhao A.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation
Scripta Materialia | Year: 2014

A new method is proposed to increase the volume fraction of retained austenite and enhance the mechanical performance of low-alloyed steels. By deliberately preserving a small amount of interlath-retained austenite before annealing at a relatively high temperature, new intercritical austenite was thus encouraged to adopt an acicular morphology between laths. Therefore, the formation of blocky austenite, which usually exists during intercritical annealing of martensitic microstructure, was suppressed, which led to enhancement of retained austenite content and mechanical properties. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Ding R.,University of Science and Technology Beijing | Tang D.,University of Science and Technology Beijing | Tang D.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Zhao A.,University of Science and Technology Beijing | And 4 more authors.
Materials and Design | Year: 2015

In this study, ultrafine grained (UFG) quenching and partitioning steels was achieved by using tempered and deformed martensite as the pre-microstructure of the quenching and partitioning treatment. Compared with those manufactured through the conventional routine, superior mechanical properties were realized in UFG steels by using tempered and deformed martensite as the pre-microstructure of the quenching and partitioning treatment. The grain subdivision mechanism during deformation and the microstructure evolution during heating were investigated. Effect of carbide on the grain subdivision and its pinning effect against grain growth is highlighted. The proposed method produced UFG steels with considerable amount of retained austenite, which contributed to the enhanced mechanical properties of investigated steels. © 2015 Elsevier Ltd.


Liu J.-L.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Liu J.-L.,Wuhan University of Technology | Huang H.-Y.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Xie J.-X.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation
International Journal of Minerals, Metallurgy and Materials | Year: 2016

The effect of aging treatment on the superelasticity and martensitic transformation critical stress in columnar-grained Cu71Al18Mn11 shape memory alloy (SMA) at the temperature ranging from 250°C to 400°C was investigated. The microstructure evolution during the aging treatment was characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results show that the plate-like bainite precipitates distribute homogeneously within austenitic grains and at grain boundaries. The volume fraction of bainite increases with the increase in aging temperature and aging time, which substantially improves the martensitic transformation critical stress of the alloy, whereas the bainite only slightly affects the superelasticity. This behavior is attributed to a coherent relationship between the bainite and the austenite, as well as to the bainite and the martensite exhibiting the same crystal structure. The variations of the martensitic transformation critical stress and the superelasticity of columnar-grained Cu71Al18Mn11 SMA with aging temperature and aging time are described by the Austin–Rickett equation, where the activation energy of bainite precipitation is 77.2 kJ·mol−1. Finally, a columnar-grained Cu71Al18Mn11 SMA with both excellent superelasticity (5%–9%) and high martensitic transformation critical stress (443–677 MPa) is obtained through the application of the appropriate aging treatments. © 2016, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.


Jiang Y.B.,University of Science and Technology Beijing | Jiang Y.B.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Zhang Z.H.,University of Science and Technology Beijing | Zhang Z.H.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | And 2 more authors.
Materials Science Forum | Year: 2014

Effect of isothermal annealing on the microstructure evolution of the cold-rolled Mg-9Al-1Zn alloy strip was investigated. It is found that the competition between the precipitation of β-Mg17Al12 phase and recrystallization of α-Mg matrix occur under the conditions of various annealing temperature and time. At a low annealing temperature (523K), the β-Mg17Al12 particles precipitate preferentially at locally high deformation area and grow into the lamellar-cluster with an increase in the annealing time, retarding the recrystallization of α-Mg matrix. With raising the annealing temperature (573 ~ 623K), both the precipitation of β-Mg17Al12 particles and recrystallization of α-Mg matrix take place. Both recrystallization and grain growth are prone to proceed without precipitation of β-Mg17Al12 particles when the annealing temperature is 673K. A mechanism for the competitive behavior between the precipitation of β-Mg17Al12 phase and recrystallization of α-Mg matrix at various annealing conditions is discussed. © (2014) Trans Tech Publications, Switzerland.


Jiang Y.B.,University of Science and Technology Beijing | Jiang Y.B.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Guan L.,Beijing Institute of Technology | Tang G.Y.,Tsinghua University
Materials Science Forum | Year: 2014

The effect of electropulsing treatment (EPT) on the microstructure and mechanical properties of the cold-rolled Mg-6Al-1Zn alloy strip was investigated. It is found that EPT accelerated the recrystallization behaviour of the cold-rolled Mg-6Al-1Zn alloy strip at a relatively low temperature within a short time of 14 seconds. When the temperature of EPT was 423 K, recovery of Mg matrix happened and few β-Mg17Al12 phaseprecipitated in the Mg matrix. With increasing the temperature to 463 K, recrystallization occurred, accompanying dissolution of β-Mg17Al12 phase. When the temperature was increased to 483 K, complete recrystallization took place and obtained fine microstructure of quasi-single-phase-recrystallized grains. The elongation to failurewas increased from the 6.3% of the rolled strip to 23.5%, while the tensile strength was decreased from 368 MPa to 300 MPa. Further increasing the temperature of EPT, the apparent grain growth occurred and both the tensile strength and elongation to failure reduced. A mechanism for rapid recrystallization process during EPT was discussed. © (2014) Trans Tech Publications, Switzerland.


Xie J.-X.,University of Science and Technology Beijing | Xie J.-X.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Liu J.-L.,University of Science and Technology Beijing | Huang H.-Y.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation
Rare Metals | Year: 2015

The effects of various structure factors on the properties (superelasticity mainly) of Cu-based shape memory alloys (SMAs) were systematically evaluated in this review article through literatures combining with our work. It is concluded that besides the decisive role of grain orientation, the grain boundary (GB) characteristics also play important roles in the superelasticity, which include GB area, GB type, GB morphology and GB direction in descending order of the effect significance. According to the above results, the prior principles of structure design are proposed for high-performance Cu-based SMAs from most to least important: (1) obtaining grain orientation with high phase transformation strain; (2) increasing grain size or reducing GB area; (3) obtaining straight low-energy GBs, especially low-angle GBs; (4) trying to make GB direction parallel to external stress. Consistent with the main or all principles, the bamboo-like-grained and columnar-grained (CG) Cu-based SMAs show excellent comprehensive properties. © 2015, The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg.


He J.,University of Science and Technology Beijing | He J.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Zhao A.,University of Science and Technology Beijing | Zhao A.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | And 5 more authors.
Materials Today: Proceedings | Year: 2015

In this paper, the acceleration effect of warm rolling process on bainite transformation at 230°C for a high-carbon, silicon-rich steel with nanostructured bainite was studied. The warm rolling temperature was determined by simulation experiments using a Gleeble 3500 thermal and mechanical testing system. It is found that the bainite transformation will take more than 50hours to complete at the same isothermal temperature without warm rolling, while the incubation time can be shortened from 6hours to 0.5hours when warm rolling was conducted within a temperature range 300-600°C. In addition, the quantitative X-ray analysis indicated that the volume fraction of retained austenite after warm rolling (total strain 0.20) and isothermal transformation for 20hours was about 33.8%, keeping a same level compared with the austempering bainite transformation process (no strain) which austenite volume fraction was about 32%. Low temperature bainite transformation can be accelerated by warm rolling effectively without compromising strength. And the ultimate tensile strength of warm rolling nanostructured bainite steel is 2127MPa. © 2015 The Authors.


Huang H.-Y.,University of Science and Technology Beijing | Huang H.-Y.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Wang Y.,University of Science and Technology Beijing | Xie J.-X.,University of Science and Technology Beijing | Xie J.-X.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation
Materials Science and Engineering A | Year: 2014

The microstructure evolution and stress-induced phase transformation (SIPT) characteristics of continuous columnar-grained (CCG) polycrystalline Cu-12wt%Al alloy during the tensile deformation process were investigated to understand the ductility enhancement mechanism, which shows a tensile elongation of 28%, nine times as high as that of the conventional as-cast polycrystalline counterpart. The results show that the CCG alloy has highly-oriented 〈001〉β texture and straight low-energy grain boundaries (GBs) along solidification direction, which significantly promote grains compatibility during plastic deformation. Additionally, besides β1'→α1' transformation, β1'→γ1'→α1' SIPT was also observed simultaneously in the CCG polycrystalline Cu-12wt%Al alloy, which is different from single crystalline and conventional polycrystalline counterparts. As a consequence of the special phase transformations, high phase transformation plasticity (15-20%) and prominent subsequent plastic deformation (8-13%) of the phase transformation product α1' martensite can be obtained. © 2013 Elsevier B.V.


Liu J.-L.,University of Science and Technology Beijing | Huang H.-Y.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Xie J.-X.,University of Science and Technology Beijing | Xie J.-X.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation
Materials and Design | Year: 2015

The columnar-grained (CG) Cu-Al-Mn shape memory alloy samples possess a strong <. 001>-oriented texture along the solidification direction (SD) and straight low-energy grain boundaries fabricated by unidirectional solidification technique. When the angle between tensile direction and the SD ranged from 0° to 90° at the tensile tests, the superelasticity of samples changed in a "V" shape and showed a large anisotropy. Meanwhile, the martensite transformation critical stress of the CG Cu-Al-Mn samples increased from 258.5 MPa for 0° to 521.9 MPa for 45°, and then decreased to 324.3 MPa. The large anisotropy of the superelasticity was attributed to the combined effects of grain orientation and grain boundaries, wherein the influence of the grain boundaries had an obvious dependence on orientation. The potential applications of CG Cu-Al-Mn alloys as anisotropic shock isolators and dampers in high rise buildings and precision instruments were also proposed. © 2015 Elsevier B.V.


Liu J.-L.,University of Science and Technology Beijing | Huang H.-Y.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation | Xie J.-X.,University of Science and Technology Beijing | Xie J.-X.,Beijing Laboratory of Metallic Materials and Processing for Modern Transportation
Materials and Design | Year: 2014

Through texture and grain boundary control by continuous unidirectional solidification, the continuous columnar-grained polycrystalline Cu71.8Al17.8Mn10.4 shape memory alloys were prepared and possess a strong 〈001Y texture along the solidification direction and straight low-energy grain boundary. The alloys show excellent superelasticity of 10.1% improved from 3% for ordinary polycrystalline counterpart and with a tiny residual strain of less than 0.3% after unloading. There are some reasons for the enhanced superelasticity: (1) The martensitic transformation of all grains with strong 〈001Y-oriented texture occur at the same time under the tensile loading, which can avoid the significant stress concentration problem and transformation strain incompatibility at the grain boundaries due to the high elastic anisotropy in ordinary polycrystalline alloy. (2) High phase transformation strain can be obtained along 〈001Y grain orientation. (3) Straight low-energy grain boundary and the absence of grain boundary triple junctions of continuous columnar-grained polycrystals can significantly reduce the blockage of martensitic transformation at the grain boundaries. These results provide a reference to structure design of high-performance polycrystalline Cu-based shape memory alloys. © 2014 Elsevier Ltd.

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