Engineering topics

Ajo, Henry M.

Publications and source records attributed to Ajo, Henry M..

3 records

DOE OSTI2024

Magnetic Materials Research at SRNL

Introduction – What are Magnetic Materials? Magnetic materials are crystalline solids which below a certain temperature, known as the ordering temperature, display spontaneous order in their magnetic moments. Results • Enhanced thermal stability and saturation magnetization with Y substitution in Ce2Fe14B based permanent magnets • Discovered a new ferromagnetic phase transition at TC = 62.9 K in (Dy1/3Mo2/3)2AlC and validated the two previously reported low temperature magnetic phases Characterization of Magnetic Materials Raw high purity materials are melted together to synthesize a crystalline sample using an arc melter at Savannah River National Laboratory (SRNL). Use high energy ball milling to form a hard/soft magnetic composite using Y substituted Ce2Fe14B. Finish structural characterization on γ- irradiated (RE1/3Mo2/3)2AlC (RE = Rare Earth) MAX samples. Unit Cell Lattice Points

Bretana, Alex↗

DOE OSTI2024

Characterization of Stress-Corrosion-Cracking in Plutonium-Bearing Storage Containers

Introduction • The Integrated Surveillance Program, under the Department of Energy, is responsible for the periodic surveillance of storage containers containing plutonium-bearing materials. • The container-packages are designed to isolate the materials for 50 to 100 years with minimal surveillance. • During monitoring, corrosion-pitting and stress-corrosion-cracking (SCC) has been identified in some of the inner-cans near the weld regions. • SCC through wall penetration would result in an undesired increased risk of leakage. • An investigation is in progress to identify and characterize corrosion events to determine the prevalence of corrosion features and the likelihood of a throughwall breach. • Here, we discuss the characterization efforts carried out by Scanning Electron Microscopy (SEM), including 3D-tomography by Focused Ion Beam (FIB) methods.

Perez, Emmanuel E.↗

DOE OSTI2024

Magnetic Materials Research at SRNL

Fig: Rietveld Refinement of room temperature PXRD data for annealed Ce2Fe14B (left panel), (Y0.1Ce1.9)Fe14B (middle panel), and (Lu0.1Ce1.90)Fe14B (right panel) alloys. All annealed alloys plotted are composed primarily of Ce2Fe14B phase with small α-Fe impurities. Vertical blue ticks correspond to the position of the calculated Bragg peaks of all phases (from top to bottom, 2-14-1 and α-Fe). Fig: (Left Panel) Field dependent magnetization measurements on aligned powder with the magnetic field applied along the easy direction for annealed Ce2Fe14B and (YxCe2-x)Fe14B (x=0.1, 0.2, 0.3, 0.4, 0.5) alloys. (Middle Panel) Field dependent magnetization measurements on aligned powder with the magnetic field applied along the hard direction for annealed Ce2Fe14B and (YxCe2-x)Fe14B (x=0.1, 0.2, 0.3, 0.4, 0.5) alloys. (Right Panel) The saturation magnetization of Ce2Fe14B and (YxCe2-x)Fe14B (x=0.1, 0.2, 0.3, 0.4, 0.5) alloys as determined from easy axis field dependent magnetization measurements.

Bretana, Alex↗