| Y-Co二元系的研究 | |
| 苏旭平 | |
| Subtype | 硕士 |
| Thesis Advisor | 庄育智 |
| 1989-09-14 | |
| Degree Grantor | 中国科学院金属研究所 |
| Place of Conferral | 中国科学院金属研究所 |
| Keyword | 相关系 化合物 相图 |
| Abstract | 本文用金相、差热分析、X射线衍射分析、电子摆针微区成分分析等手段对Y-Co系相图及化合物进行了全面研究。Y-Co系包含11个稳定化合物，其中Y_3Co、YgCo_5、YCo、Y_2Co_3、YCo_2、YCo_3和Y_2Co_7为包晶反应生成；YCo_5和Y_2Co_(17)为同成分熔化生成，同成分熔化温度分别为：1345 ℃、1357 ℃；Y_9Co_7和Y_6Co_7为包析反应生成，Y_6Co_7为新发现的化合物，是由YCo与Y_2Co_3在775 ℃包析反应生成。另外该系还存在三个共晶反应，它们的成分及反应温度分别为：37at%Co、738 ℃，87at%Co、1134 ℃，93at%Co、1340 ℃。测定了钇在钴中的固溶度。在高温Y_2Co_(17)和YCo_5化合物有一定的均匀化范围，其余金属化合物都是化学计量的或几乎是化学计量的。YCo_5化合物在830 ℃左右局部Spinodal分解成Y_2Co_7和Y_2Co_(17)化合物。铸态存在一个亚稳相Y_3Co_2，在约700 ℃保温短时间即分解成Y_8Co_5和 Y_9Co_7两化合物。 |
| Other Abstract | A constitutional diagram of the yttrium-cobalt system was determined by optical microscopy, differential thermal analysis, X-ray diffraction and electron microprobe techniques. This system exhibits (i) seven peritectic reactions forming following intermetallic compounds: Y_3Co, Y_8Co_5, YCo, Y_2Co_3, YCo_2, YCo_3 and Y_2Co_7 respectively; (ii) two peritectoid reactions forming Y_9Co_7 and Y_6Co_7 respectively, the Y_6Co_7 is a new phase which had not been reported before; (iii) two congruently melting phases Y_2Co_(17), YCo_5; (iv) three eutectic reactions occurring isothermally at 738 ℃, 1334 ℃ and 1340 ℃ with eutectic containing 37at%Co, 87at%Co and 93at%Co respectively. The solid solubility of yttrium in cobalt is about 0.04wt% (0.03at%)Co at 1200 ℃ and negligible at the room temperature. Both Y_2Co_(17) phase and YCo_5 phase have a large homogeneity region at the high temperature. There is one metastable phase Y_3Co_2 in as-cast alloy containing 40at% Co. The Y_3Co_2 decomposes into Y_8Co_5 and Y_9Co_7 at 700 ℃. |
| Pages | 50 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/17407 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 苏旭平. Y-Co二元系的研究[D]. 中国科学院金属研究所. 中国科学院金属研究所,1989. |
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