Crystalline-amorphous transformation of precipitates in Zircaloy under electron irradiation

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:7035183

Motta, A M.T.

The common Zr{sub 2}(Ni,Fe) intermetallic precipitates in Zircaloy-2 were irradiated with 1.5-MeV electrons in a high-voltage electron microscope until amorphous. The dose to amorphization, measured in displacements per atom (dpa) was recorded as a function of temperature and dose rate. The results show that the dose to amorphization rises exponentially with temperature and is lower for higher dose rates. A theoretical model was developed to predict the onset of the C-A transformation based on the accumulation of free energy in the lattice during irradiation. The mechanisms for accumulation were increased in structural disorder (point defect concentration) and chemical disorder (anti-site defects). The point-defect balances were solved for the thin foil case. The surface sink was found to annihilate the more mobile interstitials while the vacancy concentration steadily increased in the lattice. The temperature and dose-rate dependences of the dose-to-amorphization were contained in the expression for the vacancy increase as a function of dose. Chemical and structural disorder were found to contribute comparable amounts to the irradiation-induced free energy increase. The experimental results were satisfactorily explained for reasonable values of the fitting parameters.

• Research Organization: California Univ., Berkeley, CA (USA)
• OSTI ID: 7035183
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360106* -- Metals & Alloys-- Radiation Effects
ALLOY-ZR98SN-2
ALLOYS
AMORPHOUS STATE
BEAMS
CHROMIUM ADDITIONS
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRON BEAMS
ENERGY
ENERGY RANGE
FREE ENERGY
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ADDITIONS
IRON ALLOYS
LEPTON BEAMS
MATERIALS
MEV RANGE
MEV RANGE 01-10
NICKEL ADDITIONS
NICKEL ALLOYS
PARTICLE BEAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
POINT DEFECTS
RADIATION EFFECTS
RADIOINDUCTION
THERMODYNAMIC PROPERTIES
TIN ALLOYS
ZIRCALOY
ZIRCALOY 2
ZIRCONIUM ALLOY
ZIRCONIUM BASE ALLOYS