超伝導YBCO酸化物におけるファセット型123結晶の包晶凝固シミュレーション

• 森 信幸

  九州大学大学院工学研究科材料物性工学専攻

• 大城 桂作

  九州大学大学院工学研究科物質プロセス工学専攻

書誌事項

タイトル別名

• Numerical Simulation of Peritectic Growth of Faceted 123 Crystals in Superconductive YBCO Oxides
• チョウデンドウ YBCO サンカブツ ニ オケル ファセットガタ 123 ケッショウ ノ ホウショウギョウコ シミュレーション

抄録

To clarify the solidification mechanism of the faceted 123(YBa₂Cu₃O_7−x) crystals from liquid+primary 211(Y₂BaCuO₅) phases of the superconductive Y-Ba-Cu-oxides (YBCO), new 2-dimensional numerical simulation method of the growth process of the faceted peritectic crystal is proposed and appreciated with the experimental results. The basic model of peritectic solidification of the 123 phase consists of three sequential primitive processes: (a) growth of faceted peritectic crystals, (b) melting of primary particles in the liquid, and (c) solute diffusion in the liquid. Two-dimensional numerical calculations for peritectic growth of the faceted 123 phase with solute diffusion in the liquid are carried out by the explicit control volume finite difference method (FDM) to calculate distribution of 211 particles in the 123 phase and solute distribution in the liquid from the initial distribution of 211 particles in the liquid. The normal growth rate (R) of a facet plane is given by the following relation, which suggests the screw dislocation mechanism: R=a_g·ΔT_k², where a_g is a kinetic growth constant, and ΔT_k is the kinetic undercooling on the faceted interface. The melting rate of superheated 211-particles in the liquid is also assumed to be given by the above equation with a kinetic melting constant (a_m). The effects of the ratio (a_g⁄a_m), the diffusion coefficient in the bulk liquid, the interface energy of 211 particles, and the local undercooling caused by non-uniform distribution of 211 particles on the growth process are examined in the calculations. The distributions of residual 211 particles and liquid pools in the faceted 123 crystals are calculated form the experimentally obtained log-normal distributions of 211 particles in the liquid of YBCO quenched during unidirectional solidification, and the calculated distributions agree well with the experimental results.

収録刊行物

• 日本金属学会誌

  日本金属学会誌 62 (12), 1109-1116, 1998

  公益社団法人 日本金属学会

キーワード

• superconductor
• numerical simulation
• YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7−<I>x</I></SUB>
• peritectic, oxide
• facet
• solidification
• yttrium-barium-copper-oxides; YBCO
• Y<SUB>2</SUB>BaCuO<SUB>5</SUB>

詳細情報

• CRID: 1390001206491534976
• NII論文ID: 130007342144
• NII論文ID: 10002548104
• NII書誌ID: AN00187860
• DOI: 10.2320/jinstmet1952.62.12_1109
• ISSN: 18806880
• ISSN: 24337501
• ISSN: 00214876
• ISSN: http://id.crossref.org/issn/00214426
• NDL書誌ID: 971208
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I971208
• Web Site: https://www.jstage.jst.go.jp/article/jinstmet1952/62/12/62_12_1109/_pdf
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可