Material Specification for Y:123; [Y-Ba-Cu-O]
Process: Solid State Reaction
Notes: The authors cite D.L. Kaiser et al., Appl. Phys. Lett., Vol. 51, 1040 (1987) and J. Cryst. Growth, Vol. 85, 593 (1987), and summarize the procedure as follows. "Single crystals were grown from Ba-Y-Cu-O melts in gold crucibles... The as-grown crystals were subsequently annealed in oxygen at 420 °C for 80 h... The crystals were well-formed, rectangular parallelepipeds... with typical dimensions of 100-300 µm in the a/b directions and 80-120 µm in the c direction. As-grown crystals exhibited characteristic {110} twin planes... Selected crystals were detwinned via a thermomechanical process to produce single-domain crystals... Twinned and detwinned crystals were mounted on glass slides with a thin layer of epoxy in preparation for the microindentation studies."
Formula: YBa2Cu3O7-x
Informal Name: Y:123
Chemical Family: Y-Ba-Cu-O
Chemical Class: Oxide
Structure Type: Single Crystal
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Hardness for Y:123; [Y-Ba-Cu-O]
| Crystal Condition () |
Crystal Face () |
Hardness (GPa) |
| detwinned |
a/b |
9.4 ± 1.5 |
| twinned |
a/b |
9.5 ± 0.8 |
| twinned |
a/b |
9.8 ± 0.7 |
Vickers indentation
"Vickers diamond pyramid indentations were used to introduce cracks into the single crystals at applied loads ranging from 0.25 N to 0.5 N for various orientations in air and distilled water... Crack lengths were measured in the optical microscope approximately 3 min after indentation... Values of the fracture toughness or critical stress intensity factor (K
c) and hardness (H) were calculated using the equations set forth in G.R.Anstis et al., J. Am. Ceram. Soc., Vol. 64, 533(1981):
H = P/2d
2, and K
c = 0.016 (E/H)
1/2 P/c
(3/2),
where P is the applied indentation load, 2d is the indentation diagonal, E is the elastic constant, and c is the radial crack length measured from the center of the indent to the crack tip."
Cautions: Evaluated Data
Fracture Toughness for Y:123; [Y-Ba-Cu-O]
| Crystal Condition () |
Crystal Face () |
Measurement Condition () |
Fracture Toughness (MPa·m1/2) |
| detwinned |
c |
//a, air |
0.59 ± 0.09 |
| detwinned |
c |
//b, air |
0.47 ± 0.12 |
| twinned |
c |
air |
0.66 ± 0.08 |
| twinned |
c |
H2O |
0.43 ± 0.04 |
| twinned |
a/b |
//c |
0.80 ± 0.06 |
| twinned |
a/b |
//ab-plane |
0.32 ± 0.07 |
Vickers indentation
"Vickers diamond pyramid indentations were used to introduce cracks into the single crystals at applied loads ranging from 0.25 N to 0.5 N for various orientations in air and distilled water... Crack lengths were measured in the optical microscope approximately 3 min after indentation... Values of the fracture toughness or critical stress intensity factor (K
c) and hardness (H) were calculated using the equations set forth in G.R.Anstis et al., J. Am. Ceram. Soc., Vol. 64, 533(1981):
H = P/2d
2, and K
c = 0.016 (E/H)
1/2 P/c
(3/2),
where P is the applied indentation load, 2d is the indentation diagonal, E is the elastic constant, and c is the radial crack length measured from the center of the indent to the crack tip."
Cautions: Evaluated Data
"... it was necessary to make some assumptions regarding the orientation dependence of the elastic constants. ... using a tetragonally symmetric elastic constant matrix determined by Reichardt et al., Supercond. Sci. Technol. 1 (1988) 173, ...
------ Condition -------- --E(GPa)--
c face, detwinned, air 157
c face, twinned 157
a/b face, twinned, air
perpendicular to basal 157
parallel to basal 89
... The values ... may vary as more precise measurements become available, affecting calculated E values and thus K
c."
