Title :
An evaluation of mechanical properties of YBaCuO and (Sm,Gd)BaCuO bulk superconductors using Vickers hardness test at cryogenic temperatures
Author :
Yoshino, Y. ; Iwabuchi, A. ; Katagiri, K. ; Noto, K. ; Sakai, N. ; Murakami, M.
Author_Institution :
Japan Soc. of the Promotion of Sci., Iwate Univ., Morioka, Japan
fDate :
3/1/2002 12:00:00 AM
Abstract :
Vickers hardness properties of bulk superconductors have been investigated to estimate the mechanical properties of bulk materials. However, the test at cryogenic temperatures had not been conducted at all. Then we conducted Vickers hardness test on (001) plane of YBaCuO and (Sm,Gd)BaCuO bulk superconductors from 40 to 293 K. The hardness of YBaCuO and (Sm,Gd)BaCuO increased with decreasing temperature up to 19 000 MPa and 10 000 MPa, respectively. Furthermore, the cracks caused by the indentation were observed with SEM, and the fracture toughness KIC at cryogenic temperatures was calculated. The KIC of YBaCuO and (Sm,Gd)BaCuO decreased with decreasing temperature to 0.6 MPa√m and 0.8 MPa√m, respectively.
Keywords :
Vickers hardness; barium compounds; fracture toughness; gadolinium compounds; high-temperature superconductors; indentation; microcracks; plastic deformation; samarium compounds; twinning; yttrium compounds; (SmGd)BaCuO; 40 to 293 K; SEM images; Vickers hardness properties; YBaCuO; bulk superconductors; crack propagation; cryogenic temperatures; deformation mechanism; fracture toughness; high temperature superconductors; indentation; intrinsic brittleness; mechanical properties; microcracks; temperature dependence; twinning deformation; voids; Conducting materials; Cryogenics; Magnetic fields; Magnetic materials; Materials testing; Mechanical factors; Superconducting materials; Superconductivity; Temperature; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2002.1018747
