Material Specification for Y:123; [Y-Ba-Cu-O:Ag]
Process: Solid State Reaction
Notes: "Material preparation required the blending of four compositions of 1-2-3 constituents with Ag2O powder, corresponding to 0, 9.5, 19 and 28 wt.% silver metal in the microstructure. The commercially available stoichiometric 1-2-3 powder ("123" Hi-Tc powder, SSC, Inc. Bothell, WA 98011) has an average particle size of 3 µm, with 90% of all particles smaller than 8 µm in diameter... The blended powders were pressed into beams at 53 MPa, followed by sintering according to the following thermal cycle. Specimens were heated to 350 °C in flowing oxygen at a rate of 180 °C/h, then to 900 °C at 60 °C/h. They were then held for 4 h at 900 °C before further heating to the sintering temperature of 940 °C at 10 °C/h. After a 40 h hold at 940 °C, the specimens were cooled to 550 °C at 10 °C/h. A 6 h hold at 550 °C was followed by cooling to 350 °C at 60 °C/h, then finally to room temperature at 180 °C/h."
Formula: YBa2Cu3O7•xAg
Informal Name: Y:123
Chemical Family: Y-Ba-Cu-O:Ag
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Fracture Toughness for Y:123; [Y-Ba-Cu-O:Ag]
| Mass Fraction of Ag (%) |
Fracture Toughness (MPa·m1/2) |
| 0.0 |
1.3 ± 0.1 |
| 9.3 |
1.9 ± 0.1 |
| 18.6 |
3.6 ± 0.5 |
| 27.5 |
2.9 ± 0.1 |
Measurement Method: Single edge notch beam
"The specimen blanks were then sliced to nominal dimensions of 50 mm x 7 mm x 7mm for notching, in conformance with the geometric requirements of the single edge notch beam... specimen... The chevron notches were dry cut to a dimensionless notch depth a/W, of 0.36 to 0.44, using a 0.254 mm thick diamond saw blade mounted to a numerically controlled slicing machine. A span-to-width ratio of 6 to 8 was maintained for the three-point flexure specimens, loaded over a span of 40 mm. Instantaneous stress intensity factors for the chevron notch specimens are calculated from the relationship:
K
Ii = (P
i/B_W)Y
i where P
i is the load, B the specimen thickness, W the specimen width, and Y
i is the corresponding geometry correction factor. The instantaneous stress intensity factor, K
Ii, becomes the critical fracture toughness, K
IC, at P
i = P
max."
Cautions: Evaluated Data
Digitized data were obtained from Figure 3 of the paper.
