scholarly journals Fabrication of a Simple Materials System for Study of Hg in a Stainless Steel

1998 ◽  
Vol 540 ◽  
Author(s):  
Charles W. Allen ◽  
Anthony W. Mccormick ◽  
Bernard J. Kestel ◽  
Peter M. Baldo ◽  
Nestor J. Zaluzec ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Elevated Temperatures ◽  
National Laboratory ◽  
In Situ Tem ◽  
Engineering System ◽  
Oak Ridge ◽  
Materials Engineering ◽  
Under Construction ◽  
Intense Radiation

AbstractThe Spallation Neutron Source (SNS), currently under construction at Oak Ridge National Laboratory, is expected to employ a Hg target encased in a stainless steel. Little is known about the metallurgical behavior of this materials engineering system, which will occur in a service environment involving elevated temperatures and intense radiation. Under normal equilibrium conditions, however, Hg is known to be insoluble in and non-reactive with solid Fe and Cr but to form one or more intermetallics with Ni. Hg has been implanted into alloy 304L. After implantations at 400 and 500 °C to a fluence of 3×1016 cm−2 sub-micron sized precipitates of Hg are formed, as judged, for example, from their solidification behavior on cooling during TEM observation. The formation of such a system of microtargets and possible studies employing them as in situ TEM specimens are discussed, which can provide useful empirical information in conjunction with SNS target development.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

Small Lead and Indium Inclusions in Aluminium

1991 ◽  
Vol 235 ◽  
Author(s):  
E. Johnson ◽  
K. Hjemsted ◽  
B. Schmidt ◽  
K. K. Bourdelle ◽  
A. Johansen ◽  
...  
Keyword(s):  
Melting Point ◽  
Elevated Temperatures ◽  
Supersaturated Solution ◽  
In Situ Tem ◽  
Initial Growth ◽  
Heating And Cooling ◽  
Moiré Fringes ◽  
The Matrix ◽  
Spontaneous Phase

ABSTRACTIon implantation of lead or indium into aluminium results in spontaneous phase separation and formation of lead or indium precipitates. The precipitates grow in topotactical alignment with the matrix, giving TEM images characterized by moiré fringes. The size and density of the precipitates increase with increasing fluence until coalescence begins to occur. Implantations at elevated temperatures lead to formation of larger precipitates with well developed facets. This is particularly significant for implantations above the bulk melting point of the implanted species. Melting and solidification have been followed by in-situ TEM heating and cooling experiments. Superheating up to ∼ 50 K above the bulk melting point has been observed, and the largest inclusions melt first. Melting is associated with only partial loss of facetting of the largest inclusions. Initial growth of the inclusions occurs by trapping of atoms retained in supersaturated solution. Further growth occurs by coalescence of neighbouring inclusions in the liquid phase. Solidification is accompanied by a strong undercooling ∼ 30 K below the bulk melting point, where the smallest inclusions solidify first. Solidification is characterized by spontaneous restoration of the facets and the topotactical alignment.

scholarly journals In Situ TEM Observations of Heavy Ion Damage in Gallium Arsenide

1988 ◽  
Vol 100 ◽  
Author(s):  
M. W. Bench ◽  
I. M. Robertson ◽  
M. A. Kirk
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
In Situ Tem ◽  
Accelerator Facility ◽  
Transmission Electron ◽  
Ion Accelerator

ABSTRACTTransmission electron microscopy experiments have been performed to investigate the lattice damage created by heavy-ion bombardments in GaAs. These experiments have been performed in situ by using the HVEN - Ion Accelerator Facility at Argonne National Laboratory. The ion bcorbardments (50 keV Ar+ and Kr+) and the microscopy have been carried out at temperatures rangrin from 30 to 300 K. Ion fluences ranged from 2 × 1011 to 5 × 1013 ions cm−2.Direct-inpact amorphization is observed to occur in both n-type and semi-insulating GaAs irradiated to low ion doses at 30 K and room temperature. The probability of forming a visible defect is higher for low temperature irradiations than for room temperature irradiations. The amorphous zones formed at low temperature are stable to temperatures above 250 K. Post implantation annealing is seen to occur at room temperature for all samples irradiated to low doses until eventually all visible damage disappears.

Fracture Toughness of Stainless Steel Cladding for Evaluation of the Degraded Davis-Besse RPV Head

2006 ◽  
Author(s):  
Randy K. Nanstad ◽  
Mikhail A. Sokolov
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Pressure Vessel ◽  
National Laboratory ◽  
Nuclear Regulatory Commission ◽  
Shear Mode ◽  
Fracture Toughness Test ◽  
Test Results ◽  
Acid Attack ◽  
Oak Ridge

Boric acid attack in the reactor pressure vessel (RPV) head of the Davis-Besse (D-B) nuclear plant led to wastage through the 150-mm low alloy steel head such that the stainless steel cladding was exposed. The Heavy-Section Steel Technology (HSST) Program at Oak Ridge National Laboratory was commissioned by the Nuclear Regulatory Commission to conduct a program of testing and analysis to enable an evaluation of the structural significance of cladding defects found in the wastage cavity of the D-B head. The overall test program consisted of material characterization at 316°C (600°F) of cladding materials, pressure vessel burst tests of cladding discs with and without flaws, and extensive analytical studies. Three different cladding materials were tested and evaluated, one from an unused commercial RPV that was used for the clad-burst experiments, an archival cladding previously used for various experimental and irradiation experiments, and the cladding from the D-B head. This paper compares and discusses the fracture toughness test results conducted with the three claddings, and the fractographic analyses conducted on the clad-burst discs. Comparison of J-resistance curves for the three clad materials shows significant material variability and disparity in the results from two test specimen types. Fractographic examinations of clad-burst discs showed transition from ductile tearing to shear mode of fracture. The relationship of the cladding test results with the clad-burst results is discussed.

The local structure of Ta(v) aqua ions in high temperature fluoride- and chloride-bearing solutions: Implications for Ta transport in granite-related postmagmatic fluids

2019 ◽  
Vol 57 (6) ◽  
pp. 843-851
Author(s):  
Alan J. Anderson ◽  
Robert A. Mayanovic ◽  
Thomas Lee
Keyword(s):  
High Temperature ◽  
Local Structure ◽  
Elevated Temperatures ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Acidic Solutions ◽  
Diamond Anvil ◽  
X Ray Absorption ◽  
Photon Source

Abstract The local structure of Ta(V) in high-temperature fluoride- and chloride-bearing acidic solutions was investigated using in situ X-ray absorption spectroscopy (XAS). All XAS spectra were collected from two solutions, designated A and B, at beamline ID-20-C at the Advanced Photon Source, Argonne National Laboratory. Spectra were collected from solution A at 350 and 400 °C and from solution B at 25, 360, and 400 °C after the solutions were sealed in a hydrothermal diamond anvil cell. Solution A was prepared by dissolving Ta2O5 powder in 5% HF solution; solution B consisted of TaCl5 dissolved in 2% HF. The dominant tantalum species in solution A at elevated temperatures was TaF83–. In contrast, TaCl6–, which was the dominant complex in solution B at room temperature, disappeared as hydroxide complexes with an average ligand number between 5 and 7 became the dominant species at 350 and 400 °C. The XAS results confirm the previously recognized effect of fluoride activity on Ta speciation in hydrothermal fluids and suggest that both fluoride and hydroxide complexes play an important role in the transport of Ta in acidic fluoride-bearing solutions involved in the formation of mineralized mica-rich replacement units in granitic pegmatites.

scholarly journals Elevated-Temperature Mechanical Properties of an Advanced-Type 316 Stainless Steel1

2000 ◽  
Vol 123 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Charles R. Brinkman
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Elevated Temperature ◽  
National Laboratory ◽  
Low Carbon ◽  
Oak Ridge ◽  
Creep Fatigue ◽  
Nippon Steel Corporation ◽  
Term Creep ◽  
Product Forms

Type 316FR stainless steel is a candidate material for the Japanese demonstration fast breeder reactor plant to be built in Japan early in the next century. Like type 316L(N), it is a low-carbon grade of stainless steel with a more closely specified nitrogen content and chemistry optimized to enhance elevated-temperature performance. Early in 1994, under sponsorship of The Japan Atomic Power Company, work was initiated at Oak Ridge National Laboratory (ORNL) aimed at obtaining an elevated-temperature mechanical-properties database on a single heat of this material. The product form was 50-mm plate manufactured by the Nippon Steel Corporation. Data include results from long-term creep-rupture tests conducted at temperatures of 500 to 600°C with test times up to nearly 40.000 h, continuous-cycle strain-controlled fatigue test results over the same temperature range, limited creep-fatigue data at 550 and 600°C, and tensile test properties from room temperature to 650°C. The ORNL data were compared with data obtained from several different heats and product forms of this material obtained at Japanese laboratories. The data were also compared with results from predictive equations developed for this material and with data available for types 316 and 316L(N) stainless steel.

Development of a compact in situ polarized 3He neutron spin filter at Oak Ridge National Laboratory

2014 ◽  
Vol 85 (7) ◽  
pp. 075112 ◽  
Author(s):  
C. Y. Jiang ◽  
X. Tong ◽  
D. R. Brown ◽  
S. Chi ◽  
A. D. Christianson ◽  
...  
Keyword(s):  
National Laboratory ◽  
Neutron Spin ◽  
Spin Filter ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory
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