TY - JOUR
T1 - Tensile testing method for rare earth based bulk superconductors at liquid nitrogen temperature
AU - Kasaba, K.
AU - Katagiri, K.
AU - Murakami, A.
AU - Sato, G.
AU - Sato, T.
AU - Murakami, M.
AU - Sakai, N.
AU - Teshima, H.
AU - Sawamura, M.
PY - 2005/10/1
Y1 - 2005/10/1
N2 - Bending tests have been commonly carried out to investigate the mechanical properties of melt-processed rare earth based bulk superconductors. Tensile tests by using small specimen, however, are preferable to evaluate the detailed distribution of the mechanical properties and the intrinsic elastic modulus because no stress distributions exist in the cross-section. In this study, the tensile test method at low temperature by using specimens with the dimensions of 3 × 3 × 4 mm from Y123 and Gd123 bulks was examined. They were glued to Al alloy rods at 400 K by using epoxy resin. Tests were carried out at liquid nitrogen temperature (LNT) by using the immersion type jig. Although the bending strength in the direction perpendicular to the c-axis of the bulks at LNT is higher than that at room temperature (RT), the tensile strength at LNT was lower than that at RT. Many of specimens fractured near the interface between the specimen and the Al alloy rod at LNT. According to the finite element method analysis, it was shown that there was a peak thermal stress in the loading direction near the interface and it was significantly higher at LNT than that at RT. It was also shown that the replacement of the Al alloy rod to Ti rod of which the coefficient of thermal expansion is close to that of bulks significantly increased the tensile strength.
AB - Bending tests have been commonly carried out to investigate the mechanical properties of melt-processed rare earth based bulk superconductors. Tensile tests by using small specimen, however, are preferable to evaluate the detailed distribution of the mechanical properties and the intrinsic elastic modulus because no stress distributions exist in the cross-section. In this study, the tensile test method at low temperature by using specimens with the dimensions of 3 × 3 × 4 mm from Y123 and Gd123 bulks was examined. They were glued to Al alloy rods at 400 K by using epoxy resin. Tests were carried out at liquid nitrogen temperature (LNT) by using the immersion type jig. Although the bending strength in the direction perpendicular to the c-axis of the bulks at LNT is higher than that at room temperature (RT), the tensile strength at LNT was lower than that at RT. Many of specimens fractured near the interface between the specimen and the Al alloy rod at LNT. According to the finite element method analysis, it was shown that there was a peak thermal stress in the loading direction near the interface and it was significantly higher at LNT than that at RT. It was also shown that the replacement of the Al alloy rod to Ti rod of which the coefficient of thermal expansion is close to that of bulks significantly increased the tensile strength.
KW - FEM analysis
KW - Liquid nitrogen temperature
KW - Rare earth based bulk
KW - Tensile test
KW - Thermal stress
UR - http://www.scopus.com/inward/record.url?scp=25644436329&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=25644436329&partnerID=8YFLogxK
U2 - 10.1016/j.physc.2005.02.067
DO - 10.1016/j.physc.2005.02.067
M3 - Conference article
AN - SCOPUS:25644436329
VL - 426-431
SP - 639
EP - 643
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - I
T2 - Proceedings of the 17th International Symposium on Superconductivity (ISS 2004) Advances in Supeconductivity
Y2 - 23 November 2004 through 25 November 2004
ER -