研究論文
Chevrel相PbMo6S8線材の内部応力の解析
—実験結果との対比及びMgB2線材との比較—
キーワード:
PbMo6S8 superconducting wires,
internal stress,
residual strain,
thermal expansion coefficient
2007 年 42 巻 4 号 p. 102-107
詳細
2007 年 42 巻 4 号 p. 102-107
The internal stress and residual strain of Chevrel-phase PbMo6S8 wires were analyzed using an elastic-perfect plastic model. Comparing these results with those previously obtained from our experimental results, it was found that the order of size of the residual pre-strains qualitatively agrees with the experimental results except for part of the wires although the analyzed values were 0.2-0.4% larger than the experimental values. Concerning critical current (Ic) degradation in a small 3-layer PbMo6S8 coil using a mandrel made of alumina, the difference between the experimental result and estimated value was argued. It was concluded that it is insufficient to explain the difference even when considering the effects of hoop's strain due to electromagnetic force and the variation in the cross-sectional area of the compound layer. Moreover, the internal stress and residual strain were analyzed for six kinds of assumed MgB2 wire in which different sheaths were used. As a result, the wire with a Fe sheath had better mechanical characteristic than one with a Cu sheath in the case of using a single sheath. As for adopting composite sheaths, the wire with a Fe-barrier/Cu/Cu-Ni composite sheath had better strain characteristic as compared to the wire using a Nb-barrier/Cu/Cu-Ni sheath.
