Hydrogen Isotope Research Center - Toyama Univ.


Data Base for Tritium Solid Breeding Materials (Li2O, Li2TiO3, Li2ZrO3 and Li4SiO4) of Fusion Reactor Blankets --- Yoshiaki FUTAMURA

4. Database for Li2O

4.2 Mechanical properties

4.2.1 Young's modulus

No. Data and remark Fig. Refs.
1 E=141exp(–3.5p)[1–2.3×10-4(T–293)], (GPa)
0.07≦p≦0.20 : T=293K		 - 16, 10
2 70.0MPa (T=293K) - 10
3 60.7MPa (T=600°C) - 10
Notes1 Young's Modulus values for Li2O, Li4SiO4, Be, PCA and HT9. 4.5 6, 10
Notes2 Porosity dependence of Young's Modulus values for Li2O, Li2ZrO3 and Li4SiO4. 4.6 6, 17

4.2.2 Poisson's ratio

No. Data and remark Fig. Refs.
1 ν=0.19 (93% dense pellet) : T=293K - 18, 16
2 ν=0.16 (single crystal) : 298≦T≦1603K - 18
3 ν=0.19 (80%TD, 90% 6Li enrichment, 10 μm grain size) - 18, 11

4.2.3 Tensile strength (MPa)

No. Data and remark Fig. Refs.
1 Tensile failure strength, (MPa)
σft=195 dg-0.5exp(–4.3p)·ln(2000/T)
dg=10 μm, p=0.2, T=293K, p : porosity		 - 16
2 21MPa (T=600°C) - 16
Notes1 Calculated tensile failure strength of 80%TD Li2O, and 80%TD Li4SiO4. (PCA and HT9 curves are shown for reference purpose.) 4.7 16

4.2.4 Compressive strength (MPa)

No. Data and remark Fig. Refs.
1 σc=800dg-0.5exp(–10p)·ln(2000/T)
dg=grain diameter in μm, p : porosity		 - 16
2 28.4MPa (T=600°C) - 16
Notes1 Calculated compressive failure strength of 80%TD Li2O, 80%TD Li4SiO4. (PCA and HT9 curves are shown for reference purpose.) 4.8 16
Notes2 Porosity dependence of compressive strengths for Li2O, Li2ZrO3 and Li4SiO4 are shown for reference purpose. 4.9 6, 17

4.2.5 Bending strength (MPa)

No. Data and remark Fig. Refs.
1 σb=195dg-0.5exp(–4.3p)·ln(2000/T)
dg=10μm, p=0.2, T=293K, p : porosity		 - 16
2 50.1MPa (T=293K, 80%TD, dg=10μm) - 11
3 21.6MPa (T=600°C, 80%TD, dg=10μm) - 16
Notes1 Bending failure strength of 80%TD, (dg=10μm) Li2O. (PCA and HT9 tensile failure strengths are shown for reference purpose.) 4.10 11, 12, 16

4.2.6 Rupture strength --- No data

4.2.7 Crush strength --- No data

4.2.8 Thermal creep rate (1/s)

No. Data and remark Fig. Refs.
1 εc=8.8×102(1–p2/3) -nexp(–4.04×104/T)σn
n=5.9 : T<973K
n=5.9[1–1.1×10-3(T–973)] : 973≦T≦1123K
n=4.9 : T>1123K
0.07≦p≦0.21, 973≦T≦1223K, 4≦σ≦45 MPa 		- 16
2 4.0 μm/(m-s), (T=800°C, 20MPa) - 10
Notes1 Secondary thermal creep rate of 80%TD Li2O at 700°C. (PCA and HT9 curves are shown for reference purspose.) Secondary thermal creep rate of 80%TD Li2O at 800°C. 4.11
4.12		 16
Notes2 Compressive creep rates (10MPa, 100hr) for 80%TD Li2O and 80%TD Li4SiO4. 4.13 6

4.2.9 Vickers hardness (MPa) --- No data

4.2.10 Thermal shock resistance

No. Data and remark Fig. Refs.
1 Crack generation due to the thermal strain is determined by using the following thermal shock parameters.
R'=σf·κ·(1–ν)/Eα
  σf : tensile strength          κ : thermal conductivity
  υ : Poisson's ratio          E : Young's modulus
  α : thermal expansion coefficient
Thermal shock resistance is actually estimated by the value of κ/Eα. The value of κ/Eα at 600°C for ceramic breeder materials are shown in the following Appendix 4.2.10. 		- 6

Appendix 4.2.10 Material properties related to the generation of thermal crack in ceramic breeder materials.6)

Material κ (600°C)
(W/m-K)		 α (600°C)
(10-3K)		 E (R.T.)
(GPa)		 κ/Eα
(10-6m2/s)
Li2O 3.5 3.3 70 1.5
Li2ZrO3 1.4 1.1 70 1.8
Li4SiO4 1.9 3.6 50 1.1

4.2.11 Thermal cyclic loading properties

No. Data and remark Fig. Refs.
1 Effects of thermal cyclic loading on strength. Performed extremely well. Pebble dia. 1 mm, 92%TD, 42 μm grain size, 400~800°C heating-cooling rate of 20°C/s, up to 2000 cycles. - 27

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