Irradiation Hardening and Microstructural Evolution in Fe-Cu Model Alloys

V–4Cr–xTi (x = 0 to 4) alloys were used to investigate the additional effect of Cr, Ti and interstitial impurities on the microstructural evolution in He-irradiated V–Cr–Ti alloys to minimize radioactivity after fusion neutron irradiation. Transmission electron microscopy and atom probe tomography were carried out to the He-irradiated specimens at 500 °C with 0.5 dpa at peak damage. A flash electro-polishing method for the FIB-extracted specimen was established for the ion-irradiated vanadium alloys. The microstructural evolution of the irradiation-induced titanium-oxycarbonitride, Ti(CON) precipitates was observed and was influenced by the effect of Ti addition on the Ti(CON) precipitation. Apparent Ti(CON) precipitates formed in V-4Cr-xTi with 2% addition of Ti. In the V-4Cr-1Ti alloy, a high density Ti enriched cluster was formed. The origin of the irradiation hardening increase resulted from the size distribution of Ti(CON) precipitation from the dispersed barrier-hardening theory.

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Effect of Ti addition on microstructural evolution of V–Cr–Ti alloys to balance irradiation hardening with swelling suppression

Nuclear Materials and Energy ◽

10.1016/j.nme.2018.03.008 ◽

2018 ◽

Vol 15 ◽

pp. 122-127 ◽

Cited By ~ 2

Author(s):

K. Fukumoto ◽

K. Tone ◽

T. Onitsuka ◽

T. Ishigami

Keyword(s):

Microstructural Evolution ◽

Irradiation Hardening ◽

Ti Alloys ◽

Ti Addition

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Microstructural Evolution in Reduced TiO2

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100097089 ◽

1981 ◽

Vol 39 ◽

pp. 74-75

Author(s):

W. T. Donlon ◽

S. Shinozaki ◽

E. M. Logothetis ◽

W. Kaizer

Keyword(s):

Microstructural Evolution ◽

Point Defects ◽

Extended Defects ◽

Small Deviations ◽

Controlled Atmospheres ◽

Limited Solubility ◽

Thin Foils ◽

Heat Treated ◽

Porous Polycrystalline ◽

Crystallographic Shear

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.

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