材料期刊网

Investigation of the solute transportation coupled with heat transfer and fluid flow during twin-roll strip casting process

Yongsheng WANG , Chenxi JI , Jiongming ZHANG , Xinhua WANG , Wanjun WANG

金属学报(英文版) doi:10.1016/S1006-7191(08)60108-8

Mathematical model of solute [C] distribution in twin-roll strip casting process has been setup successfully with Calcosoft for the first time. Simulation result shows that in the center of the molten steel pool between the two rolls there is a vortex flow, which is a solute enriched area. But the highest solute concentration position is at the solidification front of the columnar grain zone near the cooling roll surface. Another solute enriched position is in the back flow above the nip point. Combined with the formation mechanism of microstructure in final as cast strip, analysis shows that solute enriched area is in the transitional area between columnar and equiaxed grain zone.

关键词: Twin-roll strip casting , null , null

Mechanisms of inclusion evolution and intra-granular acicular ferrite formation in steels containing rare earth elements

Xiaoxuan DENG , Min JIANG , Xinhua WANG

金属学报(英文版)

Inclusion characteristic and microstructure of rare earth (RE) elements containing steel were evaluated with scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), element-mapping, optical microscopy (OM), and automated feature analysis (AFA) option equipped with ASPEX PSEM. Factsage was used to calculate the equilibrium inclusion composition. Based on the calculation, an inclusion evolution mechanism was proposed. Furthermore, line scanning analysis was used to elucidate the intra-granular acicular ferrite (IAF) nucleation mechanism. The result showed that two different inclusions exist in sample steel: (Mn-Al-Si-Ti-La-Ce-O) +MnS complex inclusion and isolated MnS inclusion. Almost all nucleation sites for IAF are complex inclusions, while single MnS inclusion cannot induce IAF. A possible formation mechanism of complex inclusion is proposed based on calculated results using Factsage, which agrees well with experimental results. A Mn-depletion zone (MDZ) which exists adjacent to the (Mn-Al-Si-Ti-La-Ce-O) +MnS complex inclusion can account for the IAF formation. However, the low volume fraction (1.49~10^{- 7}) of effective inclusion may result in only 10% (volume fraction) IAF.

关键词: Intra-granular acicular ferrite , null , null , null , null

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua, Zhijin, Guizhou

稀土学报(英文版)

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Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua, Zhijin, Guizhou

稀土学报(英文版)

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Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua, Zhijin, Guizhou

稀土学报(英文版)

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Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua, Zhijin, Guizhou

稀土学报(英文版)

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Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua, Zhijin, Guizhou

稀土学报(英文版)

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Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua, Zhijin, Guizhou

稀土学报(英文版)

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Rare Earth Elements Compositions and Genesis of Xinhua Large-Scale Phosphorite Deposit in Western Guizhou, China

稀土学报(英文版)

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