Showing 232 results for Author: Ke An
Aug, 2026
ORNL Report
The automated data reduction on VULCAN is overhauled by using multithreading-capable python codes. Other than just creating reduced histogram data in GSAS format and reduce meta data as the prior mantid based routine, more automated services are included in the new reduction pipe line, including, generating GSAS-II format data, neutron and sample environment data slicing/c…
Aug, 2026
Journal
According to the Considère criterion for necking, the improvement of tensile ductility can be accomplished by designing a number of hardening mechanisms that operate successively and thus sustain a continuously increasing work hardening rate (or at least not decreasing rapidly). This work proposes a novel mechanics approach to extract the tangent moduli of each constituent…
May, 2026
Journal
GammaPrint®-7001 is a recently developed high γ′ (∼70% volume fraction) CoNi-based superalloy designed to combine high-temperature mechanical performance with laser powder bed fusion processability. Room-temperature yield strength ranged from 610 to 658 MPa and increased to 661 MPa (longitudinal) and 730 MPa (transverse) at 760 °C. The creep behavior compared favorably to…
Mar, 2026
Journal
Directed Energy Deposition (DED) offers rapid large scale fabrication, but difficulty in delivering consistent microstructures and properties hinders the use of DED fabricated components in safety or performance critical applications. Variability stems from the complex thermal cycles generated by the toolpath used to print the required geometry. Several practical methods h…
Feb, 2026
ORNL Report
Two large scale 316L stainless steel cylindrical shells were fabricated by wire arc directed energy deposition (WA DED). Residual stresses were measured by neutron diffraction, and the microstructure and mechanical properties of the printed material were characterized. Longitudinal and transverse residual stresses were compressive at the inner diameter, near neutral at mid…
Jan, 2026
Journal
High-flux neutron beams and high-efficiency detectors enable rapid neutron diffraction measurements at the Engineering Materials Diffractometer (VULCAN) at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL). To optimize beam time utilization, efficient sample exchange, alignment, and automated measurements are essential. Recent advances in artificial…
Jan, 2026
Journal
Neutron diffraction is a powerful tool for noninvasive and nondestructive characterization of materials and can be applied even in large devices such as internal combustion engines due to the high penetration power of neutrons. While proof-of-concept experiments have shown the ability to measure spatially and temporally resolved lattice strains in a small aluminum engine o…
Jan, 2026
Journal
Spontaneous and anisotropic surface segregation of W cations in LiMn1.5Ni0.5O4 particles can alter the Wulff shape and improve surface stability, thereby significantly improving the electrochemical performance. An Auger electron nanoprobe was employed to identify the anisotropic surface segregation, whereby W cations prefer to segregate to {110} surface facets to decrease…
Jan, 2026
Journal
Oxygen, one of the most abundant elements on Earth, often forms an undesired interstitial impurity or ceramic phase (such as an oxide particle) in metallic materials. Even when it adds strength, oxygen doping renders metals brittle1,2,3. Here we show that oxygen can take the form of ordered oxygen complexes, a state in between oxide particles and frequently occurring rando…
Jan, 2026
Journal
In situ neutron diffraction of the uniaxial tension test was used to study the effect of the surrounding matrix microstructure on the mechanical stability of retained austenite in high-carbon bearing steels. Comparing the samples with bainitic microstructures to those with martensitic ones, it was found that the retained austenite in a bainitic matrix starts transforming i…