高建荣
主要研究方向为金属材料的电磁悬浮无容器凝固。
个性化签名
- 姓名:高建荣
- 目前身份:
- 担任导师情况:
- 学位:
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学术头衔:
博士生导师
- 职称:-
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学科领域:
材料科学基础学科
- 研究兴趣:主要研究方向为金属材料的电磁悬浮无容器凝固。
1996年12月获西安交通大学金属材料专业博士学位。1999年9月至2003年6月获德国洪堡基金会长期资助,在德国宇航中心空间模拟研究所从事稀土永磁材料深过冷熔体中相选择方面的研究。2003年11月起被聘为教授在东北大学材料电磁过程研究教育部重点实验室工作。主要研究方向为金属材料的电磁悬浮无容器凝固。
所取得的主要研究成果如下:利用电磁悬浮技术和落管技术分别实现了钕铁硼合金大块熔体和微小液滴的深过冷,通过原位观察和显微组织分析绘制了深过冷熔体在快速凝固过程中的相选择和显微组织选择图,并提出了初生相选择的物理机制。另外,在钕铁硼合金HDDR粉末粘结磁体的研究中,发现了磁体的磁各项异性和矫顽力随脱氢阶段真空度的提高呈相反的变化趋势,据此提出了在HDDR工业中需要进行两阶段脱氢的新思路。
代表性论文如下:
1997: Effects of Co and Zr additions on microstructure and anisotropy of HDDR-treated NdFeB alloy powders
1998: Effects of reduced hydrogen pressure on magnetic properties of HDDR-treated NdFeGaB alloy powders
1999: Containerless solidification of undercooled NdFeZrB alloy droplets in a drop tube
2000: A metastable phase crystallized from undercooled NdFeCoZrGaB alloy droplets
2001: Phase formation in undercooled NdFeB alloy droplets
2002: Undercooling-dependent solidification behavior of levitated Nd14Fe79B7 alloy droplets
2003: Solidification of levitated NdFeB alloy droplets at significant bulk undercoolings
2004: Phase selection in undercooled Nd-Fe-Co-B alloy droplets
2005: Characterization of the microstructure of gas-atomized Nd-Fe-B alloy particles of non- peritectic chemical compositions
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【期刊论文】Characterization of the disproportionated NdFeCoZrB alloy by means of electron microscopy
高建荣
,-0001,():
-1年11月30日
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高建荣, J. Gao a, c, *, T. Volkmann a, S. Reutzel b, D.M. Herlach a
Journal of Alloys and Compounds 388 (2005) 235-240,-0001,():
-1年11月30日
Gas-atomized Nd-Fe-B droplets of non-peritectic chemical compositions Nd16Fe76B8, Nd17Fe74.5B8.5, and Nd18Fe73B9 were undercooledand solidified in an 8mdrop tube filled with helium. The microstructure of the received particleswas investigated by means of scanning electronmicroscopy and powder X-ray diffractometry. It was found that in each alloy composition, in excess of 71% of the particle population showsa microstructure comprising primary Nd2Fe17Bx dendrites plus interdendritic Nd2Fe14B grains plus intergranular Nd1.1Fe4B4 and Nd-richgrains, where the metastable Nd2Fe17Bx dendrites are partially or completely decomposed into a mixture of α-Fe plus Nd2Fe14B depending onparticle size. There is often a certain amount of Nd2Fe14B dendrites in these particles, resulting in a dual microstructure. On the other hand, therest of the particle population shows a microstructure consisting of primary Nd2Fe14B grains, either columnar or dendritic, plus intergranularNd1.1Fe4B4 and Nd-rich phase grains. Additionally, a tiny amount of α-Fe dendrites is formed in some of the particles independent of thetype of the microstructure. They are exclusively distributed near the particle surface, and are surrounded either by Nd2Fe14B grains or byNd2Fe17Bx grains in individual particles.
Metals, Liquid quenching, Scanning electron microscopy, X-ray diffraction analysis
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【期刊论文】Phase selection in undercooled Nd-Fe-Co-B alloy droplets
高建荣, J. Gao a, b, *, T. Volkmann a, J. Strohmenger a, D.M. Herlach a
Materials Science and Engineering A 375-377 (2004) 498-501,-0001,():
-1年11月30日
Nd14Fe69Co10B7 alloys were levitated, melted and solidified using the electromagnetic levitation technique for the purpose of studying theeffect of cobalt addition on phase selection in undercooled Nd-Fe-B alloy melts. Bulk undercoolings of up to 80K were achieved in thelevitated melt droplets. Similar to cobalt-free alloys, λ-(Fe, Co) solid solution, χ-Nd2(Fe, Co)14B compound, and the metastable χ-Nd2(Fe,Co)17Bx compound (x∼1) were solidified primarily in sequence of the increasing bulk undercooling. The critical undercoolings for theprimary formation of the ф-phase and of the x-phase were determined to be 50 and 65 K, respectively. Compositional analysis showed thatthe λ-phase has a lower cobalt concentration than that of the bulk alloys, whereas the ф-and λ-phases have a cobalt concentration close tothat of the bulk alloys. However, the cobalt concentrations of all the three phases do not change significantly with the bulk undercooling ofthe samples.
NdFeB, Cobalt addition, Undercooling, Solidification, Phase selection
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【期刊论文】S olidification of levitated Nd-Fe-B alloy droplets at significant bulk undercoolings
高建荣, J. Gao a, b*, T. Volkmann a, c, D.M. Herlach a
Journal of Alloys and Compounds 350 (2003) 344-350,-0001,():
-1年11月30日
Nd–Fe–B alloys with composition of Nd16 Fe76 B8, Nd18 Fe73 B9 and Nd22 Fe67 B11 were melted and solidified using an electromagnetic levitation technique. Two types of solidification behavior were observed depending on the bulk undercooling achieved prior to solidification. The samples with small undercoolings were solidified by the predominant primary formation of the Nd2 Fe14 B compound, whereas those with large undercoolings were solidified by the primary formation of the metastable Nd2 Fe17 Bx compound (x~1) plus the subsequent formation of Nd2 Fe14 B. The critical undercooling for the primary Nd2 Fe17 Bx formation was determined to be 40, 70 and K in the three alloy compositions, respectively. The liquidus temperature of the metastable Nd2 Fe17 Bx compound was estimated to be 1423, 1393 and 1283K, respectively. The Nd Fe B compound was found to decompose into a mixture of Fe plus Nd Fe B due to the slow cooling rates of the samples. It was suggested that the metastable Nd Fe B compound may have a lower interfacial energy than that of the stable Nd Fe B compound, hence being favored in nucleation-controlled phase selection at large undercoolings.
Transition metal alloys, Rare earth alloys, Permanent magnets, Rapid solidification
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【期刊论文】Undercooling-dependent solidification behavior of levitated Nd14Fe79B7 alloy droplets
高建荣, J. Gao ab, *, T. Volkmann ac, D.M. Herlach a
Acta Materialia 50 (2002) 3003-3012,-0001,():
-1年11月30日
Bulk Nd14Fe79B7 alloy droplets were processed using electromagnetic levitation technique for the purpose of studying their metastable solidification behavior at significant melt undercoolings. The results show that γ-Fe solid solution, Nd2Fe14B compound and the metastable Nd2Fe17Bx compound were solidified as primary phase in sequence of increasing bulk undercooling level. The critical undercoolings were determined to be 45 K and 60 K, respectively. Following primary γ-Fe formation, the Nd2Fe17Bx compound was solidified peritectically prior to the Nd2Fe14B compound. However, primary Nd2Fe14B formation was quite predominant over the whole sample volume. In case of primary Nd2Fe17Bx formation, the Nd2Fe14B compound was solidified also in a peritectic manner. The metastable Nd2Fe17Bx compound was found to decompose into α-Fe plus Nd2Fe14B during the post-solidification process. The phase selection mechanisms were discussed in terms of in-situ observations on the solidification process.
Rare earth alloys, Rapid solidification, Microstructure, Nucleation and growth
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【期刊论文】Phase formation in undercooled NdFeB alloydroplets
高建荣, J. Gao a, b, *, T. Volkmann a, c, S. Rothd, W. Loser d, D.M. Herlach a
Journal of Magnetism and Magnetic Materials 234 (2001) 313-319,-0001,():
-1年11月30日
Small droplets of NdxFe100-1.5xB0.5x alloys (x=11.8-15) were undercooled and solidified using the drop tube technique for the purpose of studying metastable phase formation in this technically important alloy system. It was found that primary g-Fe phase has been suppressed in most of the droplets due to significant undercooling levels achieved prior to solidification. Consequently, the primary crystallization either of metastable Nd2Fe17By (yE1) phase or of Nd2Fe14B phase has been favored. The former occurs predominantlyto low Nd alloys (x=11.8-13), while the latter prevails in Nd-rich alloys (x=14-15). Bymeans of thermomagnetic analysis and powder X-ray diffraction analysis, it was determined that the metastable Nd2Fe17By phase has a Curie temperature of about 100℃ and a hexagonal structure with lattice parameters as a=0.496 and c=0.416nm.
NdFeB, Drop tube, Rapid solidification, Metastable phase, Magnetic properties
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【期刊论文】A metastable phase crystallized from undercooled NdFeCoZrGaB alloy droplets
高建荣
,-0001,():
-1年11月30日
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【期刊论文】A metastable phase crystallized from undercooled NdFeCoZrGaB alloy droplets
高建荣, J. Gao a, b*, Th. Volkmann a, c, D.M. Herlach a
Journal of Alloys and Compounds 308 (2000) 296-300,-0001,():
-1年11月30日
Phase formation in rapidly solidified particles of a Nd13 Fe68.4 Co11 Zr0.1 Ga0.5 B7 alloy was investigated using the drop tube technique in order to gain further understanding of the metastable solidification behavior of undercooled Nd Fe B-based alloy melts. The results show that primary iron formation prevails in larger particles (360-1200μm), as expected for a small undercooling achieved prior to solidification. However, a new metastable phase with the TbCu-type structure was found to have crystallized directly from the undercooled liquid phase in smaller particles (80-360μm). Based on the result of compositional analysis, it was assumed that the phase may have the chemical formula Nd2(Fe,Co)17B, where x=0-1. The reasons for the metastable formation of the phase are discussed by taking into account both thermodynamic and kinetic arguments which can explain phase selection in undercooled melts.
Transition metal alloys, Rare earth alloys, Liquid quenching, Scanning electron microscopy, X-ray diffraction
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高建荣, Jian-rong Gao*, Xiao-ping Song, Xiao-tian Wang
Journal of Alloys and Compounds 267 (1998) 270-273,-0001,():
-1年11月30日
The Nd Fe 9Ga B alloy powders were treated by the HDDR process under different reduced hydrogen pressures in the range 0.2-0.8 bar, and the effects of the reduced hydrogen pressure on magnetic properties of the HDDR-treated alloy powders were investigated. It was found that the HDDR-treated alloy powders exhibit a considerable anisotropy in addition to an appropriate coercivity. As the reduced hydrogen pressure is lowered, the degree of anisotropy decreases significantly, whereas the intrinsic coercivity increases. The largest anisotropy of up to 1.62 is achieved in the powders HDDR-treated under a reduced hydrogen pressure of 0.8 bar, and the highest coercivity of 724kA m is attained in the powders HDDR-treated under 0.4 bar.
NdFeB alloys, Gallium, HDDR, Anisotropy, Permanent magnet materials
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高建荣, Jian-rong Gao, Xiao-ping Song, Xiao-tian Wang
Journal of Alloys and Compounds 248 (1997) 176-179,-0001,():
-1年11月30日
The microstructure and orientationaI anisotropy of HDDR-treated NdFeB alloy powders with Co and Zr additions were investigated. Itwas found that Co and Zr additions have significant effects on the microstructure and orientational anisotropy of HDDR-treated powders. Magnetic measurements show that the HDDR-treated NdFeCoZrB alIoy powder is anisotropic, whereas the NdFeZrB alloy powder isbasically isotropic. Microstructural observations reveal that a Zr-rich minor phase exists in the homogenized NdFeZrB alloy due to Zraddition, and remains unchanged during the HDDR process. However, Co addition depresses the formation of the Zr-rich phase, resultingnot only in a reduced volume fraction but also in a decreased Zr content of this phase. The results strongly suggest that the optimization ofthe chemical composition of the starting NdFeB alloys to promote solution of alloying elements such as Zr in Nd2Fe14B is the key to thepreparation of anisotropic HDDR powders.
NdFeB, HDDR, Microstructure, Magnetic anisotropy
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