Procedures for interface residual stress determination using neutron diffraction: Mo-coated steel gear wheel

Bruno, Giovanni; Fanara, C.; Hughes, Darren J.; Ratel, N.

doi:10.1016/j.nimb.2006.01.002

Cited by 13 publications

(2 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Closer to the surface, pseudostrain corrections are necessary due to partial immersion of the gauge volume. [ 34 ] In this study, the large dimensions of the investigated IN718 specimen render impracticable the reliable use of partial immersion methods, due to a poor signal‐to‐noise ratio in the subsurface region.…”

Section: Resultsmentioning

confidence: 99%

The Importance of Subsurface Residual Stress in Laser Powder Bed Fusion IN718

et al. 2021

Self Cite

View full text Add to dashboard Cite

The residual stress (RS) in laser powder bed fusion (LPBF) IN718 alloy samples produced using a 67°‐rotation scan strategy is investigated via laboratory X‐ray diffraction (XRD) and neutron diffraction (ND). The location dependence of the strain‐free (d0) lattice spacing in ND is evaluated using a grid array of coupons extracted from the far‐edge of the investigated specimen. No compositional spatial variation is observed in the grid array. The calculated RS fields show considerable non‐uniformity, significant stress gradients in the region from 0.6 to 2 mm below the surface, as well as subsurface maxima that cannot be accounted for via XRD. It is concluded that failure to determine such maxima would hamper a quantitative determination of RS fields by means of the stress balance method.

show abstract

Section: Resultsmentioning

confidence: 99%

The Importance of Subsurface Residual Stress in Laser Powder Bed Fusion IN718

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Monte Carlo (MC) simulations provide an efficient tool for numerical analysis of the surface effect (Lorentzen, 1997) and to some extent also for optimization of the instrument configuration (Kornmeier et al, 2011(Kornmeier et al, , 2013. Existing analytical models (Wang et al, 1998;Hutchings et al, 2005;Bruno et al, 2006;Taran & Balagurov, 2012) rely on the determination of the centre of mass of the diffracting volume. It is calculated under simplifying assumptions, such as special instrument geometry or homogeneous illumination of the gauge volume which is described as a simple geometrical object (rhomboid).…”

Section: Introductionmentioning

confidence: 99%

Analytical model for neutron diffraction peak shifts due to the surface effect

et al. 2013

View full text Add to dashboard Cite

Residual strains measured by neutron diffraction near sample boundaries can be biased by the surface effect as a result of incomplete filling of the instrumental gauge volume. This effect is manifested as anomalous shifts of diffraction lines, which can be falsely interpreted as a lattice strain unless appropriate data corrections are made. A new analytical model for the surface effect has been developed, which covers a broad variety of instrumental arrangements, including flat mosaic and bent perfect crystal monochromators, narrow slits, and Soller and radial collimators. This model permits the spurious peak shifts to be predicted quantitatively, and also allows the optimum configuration parameters, such as curvature of a focusing monochromator, which lead to suppression of the surface effect, to be calculated. The model has been thoroughly validated by comparisons with Monte Carlo simulations and experiments on a stress-free calibration sample. Predictions of the model proved to be very accurate, often within the interval of experimental errors, which makes it suitable for use in data analysis.

show abstract

Neutron Scattering

Larese

2005

Encyclopedia of Inorganic Chemistry

View full text Add to dashboard Cite

Neutron scattering, which includes diffraction (ND), inelastic (INS), quasi‐elastic (QENS), and transmission/absorption techniques, is one of the most direct ways to probe the microscopic structure, dynamics, and compositional distribution of bulk condensed matter. The properties of the neutron include: no charge; a mass, m n , equal to 1.675 × 10 −27 kg; and a magnetic moment, μ n , equal to 0.9662 × 10 −26 J T −1 . Although neutrons scatter weakly, but more or less uniformly, from the nucleus of most elements across the periodic table, there are several elements that scatter neutrons rather well. Neutrons are extremely good for investigating compounds bearing light elements, especially hydrogen, deuterium, carbon, and oxygen as well as magnetic compounds. A representative sample of the scattering properties of different nuclei (see Table 2) has been tabulated (including a graphic illustration). This is in stark contrast to X‐ray scattering, in which the principal interaction (and scattering) of the massless X‐ray photon is from the electron cloud; so the scattering amplitude increases with the atomic number. Hence, neutrons are a very versatile probe of condensed matter and have been used to characterize the atomic arrangement in crystalline and amorphous solids and liquids (magnetic materials in particular) via diffraction, lattice vibrations, molecular motion, and diffusion (both rotational and translational). Neutron beams with energies (1 meV–1 eV) and wavelengths (0.5–20 Å) are ideally suited for investigating condensed matter and can be produced in two ways. The first is from a reactor source, where a purposefully built, steady state or pulsed reactor produces neutrons as the result of nuclear fission. The second is the spallation source, where a steady or pulsed stream of energetic protons collides with a solid or liquid target; the resulting collision and thermalization process causes neutrons to be knocked out or spalled from the target. The energy and wavelength of these neutron beams can be adjusted using thermal moderators chosen to shift the peak in the energy distribution of the beam. Specially designed instrumentation that uses either crystal optics or time‐of‐flight (TOF) methods, is used to analyze the angular and energy distribution of the scattered neutrons as a result of the physical processes from the sample under study. This contribution will briefly review the production and instrumentation at both reactor and steady state sources. Because of the vast number of studies that have been performed using thermal neutrons, only a limited set of examples of how neutrons have been used to characterize crystal structure, dynamic modes in solids (phonons), diffusion and phase transformations of inorganic materials can be presented here. Finally, a brief introduction will be provided for the use of neutrons to investigate surface states of adsorbed species because, with the advent of new high intensity neutron sources and the production of nanometer scale materials with high surface to volume ratios, it is a topic that is undoubtedly going to receive significant attention in the near future.

show abstract

Procedures for interface residual stress determination using neutron diffraction: Mo-coated steel gear wheel

Cited by 13 publications

References 23 publications

The Importance of Subsurface Residual Stress in Laser Powder Bed Fusion IN718

The Importance of Subsurface Residual Stress in Laser Powder Bed Fusion IN718

Analytical model for neutron diffraction peak shifts due to the surface effect

Neutron Scattering

Contact Info

Product

Resources

About