李建国
主要从事凝固理论与凝固控制技术、金属功能材料制备方面的研究。
个性化签名
- 姓名:李建国
- 目前身份:
- 担任导师情况:
- 学位:
-
学术头衔:
博士生导师, “973”、“863”首席科学家, 国家杰出青年科学基金获得者
- 职称:-
-
学科领域:
材料合成与加工工艺
- 研究兴趣:主要从事凝固理论与凝固控制技术、金属功能材料制备方面的研究。
李建国教授,国家有突出贡献的中青年专家和国家杰出青年基金获得者,入选“新世纪百千万人才工程”。1958年生。1982年毕业于西北工业大学,分别在西北工业大学和上海交通大学获硕士和博士学位。1982-1999年在西北工业大学材料系任教,1994年被聘为教授。1995-1996年在美国加州大学从事访问教授研究。1997-1999任西北工业大学凝固技术国家重点实验室主任。2000年后任上海交通大学材料科学与工程学院教授。主要从事凝固理论与凝固控制技术、金属功能材料制备方面的研究。发明了ZMLMC超高梯度定向凝固方法,使定向凝固的温度梯度达到1000K/cm量级,被称为第四代定向凝固方法。提出并实现了电磁成形定向凝固和气膜成形定向凝固新方法,形成了可适用多种合金、连续定向凝固和单晶制备的实用技术体系。首次获得了金属系亚快速凝固树枝状向胞状的转变及其液淬界面,建立了亚快速凝固枝胞转变的理论模型。系统研究并揭示了高温合金和金属功能材料凝固组织和晶体取向形成和控制规律,实现了宽结晶温度间隔合金体系单晶和定向凝固取向的控制。承担和完成包括国家重大基础研究项目“973”、国家杰出青年基金和国家自然科学基金重大、面上项目等课题三十多项。获国家科技进步二等奖1项,省部级一等奖2项,二等奖2项、三等奖1项;在国内外刊物发表论文150篇。1994年获政府特殊津贴和光华科技奖励基金一等奖,1997年被评为中国航空工业总公司作出突出成绩的博士硕士学位获得者。曾任陕西省铸造学会副理事长,西安市铸造学会理事,中国材料研究学会青年工作委员会理事,中国航空学会材料工程专业委员会理事,<铸造技术>杂志编委,中国科学院金属研究所“快速凝固与非平衡合金国家重点实验室”学术委员会委员等。
-
主页访问
2461
-
关注数
0
-
成果阅读
432
-
成果数
10
【期刊论文】Phase and Morphological Transformation of Preformed AZ91D Magnesium Alloys in Remelting
李建国, XIA Ming-xu, a, ZHENG Hong-xing, b, YUAN Sen, c and LI Jian-guo, d
Materials Science Forum Vols. 475-479(2005) pp. 473-476,-0001,():
-1年11月30日
The phase and morphological transformation during the remelting process was investigated by isothermal soaking and rapidly quenching of preformed AZ91D magnesium alloys in semisolid state. It was revealed that the morphological transformation of preformed alloys is crucial to obtain homogenously fine spheroidal grains and affect the final forming ability. The transformation is divided into two stages, local remelting of the whole experiment and partial remelting of the respective grains, which behave as liquid bands and liquid cells structures, respectively. In the partial melting, the lower melting point phase, β-Mg17Al12, diffused to the grains boundary and center of the grains and separated to Al2Mg and Mg. The Al2Mg and Mg phases with lower melting points melt into cells structures. The final microstructure of the remelting experiments is composed of cells structures, spheroidal grains and liquid phase.
phase and morphological transformation,, magnesium alloys,, remelting,, semisolid state
-
50浏览
-
0点赞
-
0收藏
-
0分享
-
236下载
-
0评论
-
引用
【期刊论文】Rapid solidification of undercooled monotectic alloy melts
李建国, Hongxing Zheng a, Weizeng Maa, Chunsheng Zheng a, Xuefeng Guo b, Jianguo Li a, *
Materials Science and Engineering A355(2003)7/13,-0001,():
-1年11月30日
Structural evolution of bulk undercooled Ni/11.56 at.% Pb monotectic alloy was investigated systematically by using molten glass denucleating combined with superheating cycling. Within the achieved undercooling range 10/286K, the solidification structures were classified into three categories. When the undercooling was less than 50K, the structures consisted of coarse dendrites and interdendritic lead phase. With the undercooling increasing into the range of 70/232K, the dendrite clusters were refined and fine lead particles separated out from the supersaturated primary dendrite arms because of solute trapping. When the undercooling exceeded 242K, the granular grains formed and fine lead particles homogeneously distributed in the whole sample. The phase selection of high temperature melts was analyzed by adopting steady state nucleation theory. The calculated results shown that undercooled Ni/11.56 at.% Pb monotectic alloy melts solidified in the form of a(Ni) dendrites essentially during the stage of rapid solidification and after recalescence, the interdendritic residual melts solidified in the equilibrium mode. Based on the observation of the solidification structures and the calculated results with BCT dendritic growth model, it was confirmed that the granulation mechanism of the granular grains was owing to the primary dendritic disintegration and subsequent recrystallization.
High undercooling, Ni /, Pb monotectic alloy, Structural evolution, Phase selection, Granulation mechanism
-
45浏览
-
0点赞
-
0收藏
-
0分享
-
326下载
-
0评论
-
引用
【期刊论文】Microstructural Evolution of Undercooled Ni-40wt%Pb Hypermonotectic Alloy
李建国, Zheng Hongxing, a, Yu Yun, b and Li Jianguo, c
Materials Science Forum Vols. 475-479(2005) pp. 2651-2654,-0001,():
-1年11月30日
Microstructural evolution of bulk undercooled Ni-40wt%Pb hypermonotectic alloy was systematically investigated by using molten glass purification and superheating cycling. Within the achieved undercooling range, the microstructures were classified into three categories. When the undercooling was less than 50K, the microstructure consisted of coarse dendritic grain and interdendritic Pb lumps. Increasing undercooling to the range 100 to 198K, macrosegregation was serious. When the undercooling was up to 292K, refined granular grain with homogeneously distributed fine Pb particles on it formed. The granulation mechanism of granular grains was owing to dendritic disintegration and subsequent recrystallization.
Ni-Pb hypermonotectic alloy,, Undercooling,, Granulation mechanism
-
59浏览
-
0点赞
-
0收藏
-
0分享
-
196下载
-
0评论
-
引用
【期刊论文】New approach to preparing unidirectional NiMnFeGa magnetic shape memory alloy
李建国, H. X. ZHENG, W. Z. MA, Y. Y. LU, M. X. XIA, J. G. LI*
JOURNAL OF MATERIALS SCIENCE 39(2004)2557-2559,-0001,():
-1年11月30日
-
50浏览
-
0点赞
-
0收藏
-
0分享
-
149下载
-
0评论
-
引用
李建国, Chengchang Jia, *, Yun Yua, b, Weizeng Maa, Jianguo Lia, Yaohe Zhoua
Journal of Alloys and Compounds 337(2002)309-313,-0001,():
-1年11月30日
Effects of the crystal growth velocity on the crystal orientation and the microstructures of the Tb Dy Fe compound have been 0.27 0.73 1.9 investigated in an optical image zone melting furnace. The results indicate that the crystal growth velocity is very important to prepare oriented crystals of Terfenol-D. Without any seed crystals, when the velocity is lower than 5mm/ h, mainly k111l oriented crystals can be obtained. When the velocity is changed between 5mm/h and 15mm/ h, Terfenol-D crystals with k112l orientation or k110l orientation can be obtained. When the velocity is higher than 15mm/h, k113l oriented crystals can be prepared. The microstructures are in agreement with the X-ray diffraction patterns. The shape of the grains is round or that of a polygon. During the preparation of the Terfenol-D oriented crystal in an optical image zone melting furnace, the length of the molten zone, shape of the molten zone and temperature of the molten zone as well as the crystal growth velocity are important to prepare precisely oriented crystals of Terfenol-D. In the optical image zone melting furnace, a low crystal growth velocity can effectively suppress twin formation in Tb Dy Fe compounds. For the 0.27 0.73 1.9 composition of Tb Dy Fe , k111l oriented twinless single crystals or polycrystals can be possibly prepared in the furnace by well 0.27 0.73 1.9 controlling the solidification conditions.
Rare earth compounds, Crystal growth, Magnetostriction
-
40浏览
-
0点赞
-
0收藏
-
0分享
-
157下载
-
0评论
-
引用
李建国, Chengchang Ji, Jianguo Li*, Weizeng Ma, Yaohe Zhou
Journal of Alloys and Compounds 333(2002)291-295,-0001,():
-1年11月30日
In a super high temperature gradient directional solidification equipment developed by the authors, f7 mm rare earth giant magnetostrictive rods with precise <110> orientations were manufactured successfully without any seed crystal. A dispersion of only 38 exists between the k110l oriented growth direction and the axis of the rod. During the directional solidification process, there exists a certain relationship between the crystal growth morphology and the crystalline orientation degree. The crystallites-orientation degree can be determined conveniently through the observation of the crystal morphology. Under the condition of the temperature gradient of 800K/cm and the withdrawal velocity of 6mm/s|10mm/s, Tb Dy Fe rod with k110l oriented crystals can be obtained when the 0.27 0.73 1.9 solidified part of the rod reaches 20mm. When the length of the solidified part is at least 30mm, the <110> oriented crystallines can grow in a stable way.
Rare earth compounds, Transition metal compounds, Casting, Microstructure, Metallography
-
28浏览
-
0点赞
-
0收藏
-
0分享
-
150下载
-
0评论
-
引用
【期刊论文】Technique of melting and casting of (TbDy)Fe2 matrix alloy bars
李建国, Chengchang Ji, Weizeng Ma, Jianguo Li*, Yaohe Zhou
Journal of Alloys and Compounds 327(2001)220-223,-0001,():
-1年11月30日
The technique of melting and casting rare earth giant magnetostrictive bars was investigated with super high temperature gradient directional solidification equipment developed by the authors. A number of f73120-mm bars with a smooth appearance were manufactured successfully; bars with different dimensions can be obtained by changing the molds. The results reveal that the fabrication process is available and simple. Under normal melting, the losses of Tb and Dy can be controlled to within 1 and 3%, respectively. The mean composition errors of the rare earth elements Tb and Dy are less than 1.5%. Metallographic examinations reveal that the microstructure is notably dependent on the mold temperature. In addition, the full process from melting and casting to directional solidification can be performed in the same equipment, and investment in facilities for melting and casting is not required.
Transition metal alloys, Rare earth compounds, Microstructure, Magnetostriction
-
26浏览
-
0点赞
-
0收藏
-
0分享
-
116下载
-
0评论
-
引用
【期刊论文】Martensitic transformation of Ni-Fe-Ga magnetic shape memory alloys
李建国, H.X. Zheng, M.X. Xia, J. Liu, J.G. Li*
Journal of Alloys and Compounds 385(2004)144-147,-0001,():
-1年11月30日
The effects of the Ni and Ga content on the martensitic transformation of Ni-Fe-Ga alloys with composition close to Ni55Fe17.5Ga27.5 were investigated. The DSC results show that the martensitic transformation temperatures increase with Ni addition or Ga depletion. A complete thermoelastic intermartensitic transformation and retransformation in Ni58Fe17.5Ga27.5 alloy in the vicinity of 370K was observed,the hysterisis of martensitic and intermartensitic ransformation are 10.54 and 5.07 K, respectively.
Ni-Fe-Ga, Magnetic shape memory alloy, Martensitic transformation
-
37浏览
-
0点赞
-
0收藏
-
0分享
-
129下载
-
0评论
-
引用
【期刊论文】High-temperature thermoelectric properties of Ca3Co4O9
李建国, Dongli Wanga, b, Lidong Chena, *, Qin Yaoa, Jianguo Lib
Solid State Communications 129(2004)615-618,-0001,():
-1年11月30日
We have prepared polycrystalline Ca32xEuxCo4O9þd (x=0, 0.15, 0.3 and 0.45) samples using a sol-gel process followed by SPS sintering and investigated the Eu substitution effects on their high-temperature thermoelectric properties. With the Eu substitution, both the electrical resistivity and thermopower increase monotonously. This could be attributed to the decrease of hole concentrations by substitution of trivalent Eu3þ for divalent Ca2þ. The Eu substituted samples (x=0.15; x=0.3) have lower thermal conductivity than Ca3Co4O9þd due to their lower electronic and lattice thermal conductivity. The dimensionless figure of merit ZT reaches 0.3 at 1000 K for the sample of Ca2.7Eu0.3Co4O9+δ.
A., Semiconductors, B., Chemical synthesis, D., Electric transport
-
42浏览
-
0点赞
-
0收藏
-
0分享
-
241下载
-
0评论
-
引用
【期刊论文】Fabrication and thermoelectric properties of Ca3−xDyxCo4O9+δ system
李建国, Dongli Wang a, b, Lidong Chenb, ∗, Qun Wang b, Jianguo Li a
Journal of Alloys and Compounds 376(2004)58-61,-0001,():
-1年11月30日
Ca3−xDyxCo4O9+δ (x=0, 0.15, 0.3 and 0.45) polycrystalline samples have been prepared using a sol-gel process followed by SPS sintering. Their thermoelectric properties have been carefully studied from room temperature to 1000 K. The substitution of Dy for Ca results in increasing of both thermopower and electrical resistivity, which could be attributed to the decreasing of carrier concentrations. The Dy substituted samples (x=0, 0.3) have lower thermal conductivity than Ca3Co4O9+δ due to their lower electronic and lattice thermal conductivities. The dimensionless figure of merit ZT reaches 0.27 at 1000K for the sample of Ca2.7Dy0.3Co4O9+δ.
Oxides, Chemical synthesis, Electric properties, Thermal conductivity
-
55浏览
-
0点赞
-
0收藏
-
0分享
-
130下载
-
0评论
-
引用