Small-Scale Mechanical Testing on Ion Beam and Neutron Irradiated - - PowerPoint PPT Presentation
Small-Scale Mechanical Testing on Ion Beam and Neutron Irradiated Engineering Materials Peter Hosemann ; D. Frazer, H. Vo, A. Reichardt University of California at Berkeley Nuclear Engineering 1 OUTLINE Introduction/Background Mechanical
Peter Hosemann;
University of California at Berkeley Nuclear Engineering
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Reactor, Fusion,BLIP and Spallation source irradiations Ion beam irradiations
matter. Small scale mechanical testing can be useful for both! Small scale mechanical testing:
uncertainty.
etc.) Small scale mechanical testing:
ion beam irradiated materials.
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G.S.Was and Z. Jiao Univ. Michigan à 1dpa irradiation and 10 dpa irradiation à 2MeV protons at 360°C à Sample material 304SS 304SS is the material studied here Samples were provided by UM G.S.Was and Z. Jiao Univ. Michigan
cBN Ion beam penetration depth
Irradiated property Un-irradiated property
0.5 1 1.5 2 2.5 1000 2000 3000 4000 5000 Irradiated not irradiated not irradiated Nix&Gao fit irradiated Nix and Gao fit
Hardness [GPa] Indentation depth [nm] IR Depth
1 2 3 4 5 6 7 5 10 15 20 25 30 35
Hardness (GPa) Distance from the surface (um)
Irradiated Control 1 2 3 4 5 6 7 5 10 15 20 25 30 35
Hardness (GPa) Distance from the sample surface (um)
1E-22 1E-21 1E-20 1E-19 1E-18 5 10 15 20 25 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
dose rate [displacements/atom/ion]
Depth [um]
H content Atoms/cm3/ions/cm2]
H content displacemtn damage
1dpa irradiated at 360C 304 SS (protons) 10dpa irradiated at 360C 304 SS (protons) At ion beam dose of 10dpa the beam profile cannot be detected any more. à Defect saturation SRIM calculations
Tracing the hardness of the irradiated and unirradiated material
different temperatures using the Micromaterials Indenter.
Control thermocouple Control thermocouple Resistance heater Cement Sample Pendulum assembly Water cooled heat shield AlN tile Insulating base Resistance heater
Indentation size effect is well known and can be fitted with the Nix and Gao model: H.. Hardness at depth H0.. hardness at infinite depth h… depth H*…characteristic depth Macro hardness Convert Berkovich Hardness to HV Hv=0.0947*Hnano Relate HV to YS σy = 2.5 (Hv – 68) Empirical equations. G.R.Odette et al. Step 1) Step 2) Step 3) The size effect over temperature is difficult to assess; Assumption: The relative difference between nanohardness and microhardness does not change with temperature.
100 200 300 400 500 600 700 800 100 200 300 400
STRESS [MPa] Temperature (C)
UTS- Tensile YS-Tensile NI-YS Method 1
Neutron irradiated and tensile tests vs. Nanoindentation RT measurements
0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 100 200 300 h* Temperature (°C)
800H Control RT: h* vs. Temperature
Grain 1 Grain 2
Size effect is less pronounced at higher temperature à Underestimation of YS at higher temeprature
500 1000 1500 2000 Yield, Flow [MPa]
Correlation Comparison for Irradiated Alloys
Calculated vs. Measured Stress
s_Busby_H1000 s_Busby_H0 s_Milot_H1000 s_Milot_H0 s_y s_flow
20 µm Grain size typically ~20µm to ~200µm
3 different sets of pillars are manufactured in the same grain and tested using the Hysitron PI85 in-situ indenter
Penetration depth
Unirradiated Pillars Irradiated Pillars Irradiated Stopping Point Pillars
3 µm
Not irradiated
Many small slip events occurred.
10dpa region Stopping peak region
Very few but large slip events occur
Peierls stress: 𝑋 = 𝜐$%&%'() ∗ 𝑐 ∗ 𝑚 ∗ 𝑢𝑚 + 𝛿 ∗ 𝑐 ∗ 𝑚 Energy to move a dislocation through the pillar: Surface energy Energy to move the dislocation through the pillar 𝜐$%&%'() = 2𝐻 1 − 𝜉 ∗ ex p( −2𝜌 𝑒 1 − 𝜉 𝑐) b=burgers vector, G=shear modulus, γ=surface energy, ν=poison ratio, l=pillar width, tl=length of the slip plane # 𝑒𝑗𝑡𝑚𝑝𝑑𝑏𝑢𝑗𝑝𝑜𝑡 = 𝐹𝑜𝑓𝑠𝑧 𝑠𝑓𝑚𝑓𝑏𝑡𝑓𝑒 𝑒𝑣𝑠𝑗𝑜 𝑏 𝑚𝑝𝑏𝑒 𝑒𝑠𝑝𝑞 𝐹𝑜𝑓𝑠𝑧 𝑢𝑝 𝑒𝑠𝑗𝑤𝑓 𝑝𝑜𝑓 𝑒𝑗𝑡𝑚𝑝𝑑𝑏𝑢𝑗𝑝𝑜 𝒕𝒎𝒋𝒒 𝒕𝒖𝒇𝒒 𝒊𝒇𝒋𝒉𝒊𝒖 =# dislocations* burgers vector Force Displacement Energy for a load drop
Not irradiated material: ~200 - 500 dislocations pass through the pillar/slip event à50-120 nm slip step height Irradiated material: ~3500 dislocations pass through the pillar/slip event à868 nm slip step height
3 µm 3 µm
0.78dpa ORNL 2002 TEM 304 10dpa pillar test
FIB trench
3µm
Matrix Fiber Interphase
𝑄
U'%VW ∗ 𝑡𝑗𝑜θ
𝐵 = 𝑄
U'%VW ∗ 𝑑𝑝𝑡θ
𝐵 ∗ 𝜈 + τ\%U]^\
𝝊𝒆𝒇𝒄𝒑𝒐𝒆 µ
200 400 600 800 1000 1200 1400 1600 1800 2000 0.05 0.1 0.15 0.2 0.25
Stress [MPa] Strain [-]
Load cycle one Load cycle two Yield: 1544MPa Uniform elongation 4% Total elongation 8 % PTP device testing
200 400 600 800 1000 1200 1400 0.1 0.2 0.3 0.4 0.5 0.6
Engineering Stress, σ [MPa]
Engineering Strain, ε
Irr P3 G2 Irr P2, G1 Irr P1, G1 Unirr P3 G2 Unirr P2 G1 Unirr P1 G1
G1 tests are all in the same grain G2 tests are all in the same grain Hi Vo, A. Reichardt unpublished data 2016
25 Oxidized grain boundary with carbide Unoxidized grain boundary with carbide
GS3-6 Low Temperature (Sxx) GS3-12 High Temperature (GB)
In-situ Micro bending at 570°C on UO2; D. Frazer
Chilled nitrogen gas (in and out) gk Sample Cu wires for thermal contact Nano- indenter Nanoindenter Stage SEM Stage Cooling System Stage
In-situ Micro compression testing at -145C A. Lupinacci Acta Mat 2014 D. Frazer 2017 RT pillars
Outline the importance and potential impact small scale mechanical testing can have to the nuclear materials community Indentation
n 10dpa appears to be the saturation dose after which no further hardening can be detected. n Hardness over temperature follows reasonably well the tensile data over temperature.
Micro compression testing
n Significant slip step differences can be found between irradiated and unirradiated materials. n An energy balance approach to quantify the slip steps is introduced. n Evaluation of fiber/matrix composites.
Micro tensile testing:
n A significant difference between the irradiated and unirradiated strain can be
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