Neutron Diffraction Shot Peening Turbine Discs — PatSnap Eureka
Neutron Diffraction for Shot Peening Validation in Turbine Discs
Neutron diffraction is the only non-destructive technique capable of resolving full through-thickness triaxial residual stress distributions in thick-section Ni-based superalloy turbine discs — enabling rigorous, non-destructive validation of shot peening process parameters at safety-critical locations.
Why Neutron Diffraction Is the Definitive Tool for Turbine Disc Stress Profiling
Neutron diffraction occupies a uniquely privileged position among residual stress measurement techniques for turbine discs because of its deep penetration into metallic polycrystalline materials — typically tens of millimetres — without requiring material removal or specimen destruction. This penetration depth is essential for evaluating shot-peened turbine discs, where compressive stress layers coexist with bulk tensile stress distributions induced by prior forging, quenching, and heat treatment steps.
As demonstrated by the University of Science and Technology Beijing (2019), combined neutron diffraction and 2D-detector X-ray diffraction were applied to determine through-thickness residual stress distributions in powder metallurgy Ni-based superalloy discs subjected to isothermal forging, solution treatment, and aging. The results revealed that plastic deformation-induced surface stresses were substantially relieved after solution treatment, while aging treatment increased compressive radial stresses in the disc rim — information inaccessible without through-thickness non-destructive probing.
PatSnap's life sciences and engineering intelligence platform aggregates over 60 patent and literature sources addressing residual stress measurement, shot peening process validation, and surface integrity characterization across turbine and compressor components. WIPO's global patent database confirms neutron diffraction's growing role in advanced manufacturing process qualification. The National Institute of Standards and Technology (NIST) operates dedicated neutron diffraction residual stress instruments precisely because of the technique's irreplaceable role in industrial component validation.
X-ray diffraction is limited to the top 10–30 µm of surface. Neutron diffraction can resolve stress at depths of several millimetres in nickel superalloys, making it the preferred tool for confirming the depth and magnitude of the compressive zone introduced by shot peening at disc dovetail slots, disc webs, and central bore regions.
Key Data: Residual Stress Magnitudes, Stability, and Measurement Depth
All values drawn from peer-reviewed literature and patent data analysed via PatSnap Eureka. Neutron diffraction provides the subsurface resolution that surface-only XRD cannot.
Residual Stress at Turbine Disc Critical Locations (MPa)
Target compressive stresses (AECC Beijing, −900 MPa) versus XRD-measured post-peen values at slot (−650 MPa) and disc face (−770 MPa), against service tensile stresses (+450 MPa slot, +230 MPa disc face).
Shot Peen Residual Stress Stability in IN100 at 650°C
Compressive residual stresses in shot-peened IN100 survive 300 hours of thermal exposure at 650°C. Fatigue relaxation occurs only in the first load cycle; stress reversal requires applied stresses above 1000 MPa.
The Integrated Shot Peening Validation Chain for Turbine Discs
Neutron diffraction anchors each stage of the closed-loop validation chain now emerging as best practice for safety-critical rotating components.
Leading Institutions in Neutron Diffraction Validation for Turbine Disc Shot Peening
Drawn from approximately 60 patent and literature sources, these organisations define the state of the art in residual stress characterisation and process qualification for safety-critical rotating components. See how R&D teams use PatSnap to map competitive landscapes like this.
AIT Austrian Institute of Technology
Most directly focused contributor on neutron diffraction validation for IN 718 turbine disc FE models. Validated forged IN 718 compressor discs with diameters of 320 mm and thicknesses up to 25 mm, introducing temperature-dependent heat transfer coefficients to achieve model–measurement agreement.
IN 718 · FE Calibration · 2011University of Science and Technology Beijing
Published the most comprehensive multi-technique (neutron plus 2D X-ray) through-thickness residual stress characterisation of Ni-based superalloy powder metallurgy turbine discs across all fabrication stages — forging, solution treatment, and aging.
PM Ni Superalloy · Through-Thickness · 2019University West (Sweden)
Extended neutron diffraction residual stress determination to powder bed fusion-built Alloy 718, demonstrating that laser-based PBF generates higher residual stresses than electron-beam PBF, and that thermal post-treatments effectively reduce them — establishing parameter-stress-treatment relationships applicable to next-generation disc manufacturing.
PBF Alloy 718 · Process Parameters · 2020University of Dayton Research Institute
Uniquely characterised shot peen residual stress stability in IN100 under combined creep and fatigue loading at 650°C. Significant compressive residual stresses survived 300 hours of thermal exposure; residual stress reversal observed only above 1000 MPa applied stress.
IN100 · 650°C · 300 hrs · 2010Japan Atomic Energy Agency
Addressed the metrological challenge of accurate near-surface stress profiling by neutron diffraction in peened stainless steel, establishing correction procedures for gauge volume positioning errors that are critical for shot-peened turbine disc fillet radii and dovetail slot surfaces.
Gauge Volume Correction · Near-Surface · 2020AECC Beijing Institute of Aeronautical Materials
Holds multiple active Chinese patents on systematic evaluation of shot peening effectiveness at turbine disc critical locations, defining target compressive residual stresses of approximately -900 MPa at dovetail slots, disc webs, and central bores, alongside surface roughness below 1.2 µm and microhardness requirements.
−900 MPa Target · Dovetail Slot · 2020/2022How Neutron Diffraction Anchors FE Simulation Validation
All FE simulation approaches require experimental validation of the predicted residual stress field before the model can be used to certify process parameters. Neutron diffraction provides the volumetric, non-destructive through-thickness stress data that makes this possible.
Iterative Model Refinement
In the AIT study of IN 718 compressor discs, neutron diffraction measurements across the disc cross-section were compared against FE predictions at multiple through-thickness positions. The model was iteratively refined by adjusting heat transfer boundary conditions until agreement was satisfactory — then used to predict stress states in disc regions inaccessible to measurement.
Boeing's Iterative Validation Challenge
Boeing's patented systems for predicting shot peening distortion explicitly identify the iterative residual stress measurement and model adjustment cycle as the defining challenge in process validation — noting that iteratively adjusting peening parameters, manufacturing new workpieces, measuring residual stresses, and re-adjusting parameters is time-consuming and expensive. Neutron diffraction reduces the number of physical iterations required.
Prior Processing History Integration
Xi'an Jiaotong University's 2025 patent introduces a framework using the Von-Mises yield criterion, Johnson-Cook constitutive model, and Bauschinger effect to compute residual stress evolution from an initial state defined by the as-forged or as-machined condition. Neutron diffraction measurements of the pre-peening disc stress state are the natural experimental input for this model initialisation.
DEM-FEM Almen Intensity Models
Combined DEM-FEM shot peening simulation models that incorporate Almen intensity, validated against experimental stress profiles, represent the current state of the art for process parameter prediction. Neutron diffraction data serves as the highest-quality experimental reference for validating these models in disc-geometry applications, providing full three-dimensional strain tensor measurement that synchrotron X-ray and laboratory X-ray methods cannot match for thick sections.
Shot Peening Validation Beyond Aero-Engine Discs
Steam turbine blade fir-tree roots present a closely analogous scenario to aero-engine turbine discs. The fir-tree root of 1-metre last-stage steam turbine blades — which retain the blades on the disc rim — is shot-peened to introduce compressive residual stresses that resist stress corrosion cracking and corrosion fatigue. FE modelling indicates stresses above yield occur at the root in the absence of shot peening.
As noted by Nelson Mandela Metropolitan University (2010), there is an explicit absence of systematic data on stress levels and their fatigue relaxation in these components — precisely the information that neutron diffraction-based residual stress characterisation is suited to provide. The Electric Power Research Institute (EPRI) has similarly identified shot peening qualification data gaps for steam turbine components operating under corrosion fatigue conditions.
For military aero-engine compressor discs, the link between shot peening parameters, X-ray-measured compressive residual stress, and LCF life improvement has been directly quantified. Compressive residual stresses of -650 MPa (slot) and -770 MPa (disc face) were measured by XRD after shot peening of an alpha-beta titanium alloy disc, against service stresses of +450 MPa and +230 MPa respectively at those locations. Neutron diffraction would be required to confirm the full depth extent of the compressive zone relative to the stress-affected depth during the peening qualification cycle.
The PatSnap materials intelligence platform enables engineers to identify analogous shot peening validation approaches across different alloy systems and component geometries. Argonne National Laboratory's Advanced Photon Source provides synchrotron X-ray diffraction capabilities complementary to neutron diffraction for near-surface stress profiling in peened components. PatSnap's open API allows programmatic access to this patent and literature intelligence for integration into R&D workflows.
Neutron Diffraction & Shot Peening Validation — Key Questions Answered
Neutron diffraction can penetrate tens of millimetres into metallic polycrystalline materials without requiring material removal or specimen destruction. X-ray diffraction is limited to the top 10–30 µm of surface, while neutron diffraction can resolve stress at depths of several millimetres in nickel superalloys, making it the preferred tool for confirming the depth and magnitude of the compressive zone across thick disc sections.
Systematic shot peening evaluation frameworks for turbine discs, as patented by AECC Beijing Institute of Aeronautical Materials, define target compressive residual stresses of approximately -900 MPa at dovetail slots, disc webs, and central bores, alongside surface roughness below 1.2 µm.
Neutron diffraction provides volumetric, non-destructive through-thickness stress data that serves as the preferred validation dataset for FE models of disc components. In the AIT study of IN 718 compressor discs, neutron diffraction measurements across the disc cross-section were compared against FE predictions at multiple through-thickness positions, and the model was iteratively refined by adjusting heat transfer boundary conditions until agreement was satisfactory.
Shot-peened IN100 turbine disc alloy at 650°C retained significant compressive residual stresses even after 300 hours of thermal exposure. Fatigue loading caused relaxation only in the initial load cycle across the full stress distribution, and under uniform applied stresses, residual stress reversal was observed only above 1000 MPa.
Neutron diffraction measurements of peened surfaces require pre-characterization of gauge volume positioning effects using stress-free reference samples, because deviations of the gauge volume from the specimen surface introduce systematic measurement errors. This consideration is directly relevant to shot-peened turbine disc fillet radii and dovetail slot surfaces where steep gradients are expected.
The baseline residual stress state of the disc prior to shot peening — induced by forging, solution treatment, and aging — substantially influences the final shot-peened stress field. Xi'an Jiaotong University's 2025 patent introduces a framework using the Von-Mises yield criterion, Johnson-Cook constitutive model, and Bauschinger effect to compute residual stress evolution from an initial state defined by the as-forged or as-machined condition.
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References
- Residual stress distribution in Ni-based superalloy turbine discs during fabrication evaluated by neutron/X-ray diffraction measurement and thermomechanical simulation — University of Science and Technology Beijing, 2019
- Characterization of Residual Stresses in 718 Turbine Discs by Neutron Diffraction and Finite Element Modelling — AIT Austrian Institute of Technology GmbH, 2011
- Stability of shot peen residual stresses in IN100 subjected to creep and fatigue loading — University of Dayton Research Institute, 2010
- Residual Stress Distribution in Water Jet Peened Type 304 Stainless Steel — Japan Atomic Energy Agency, 2020
- Introduction to characterization of residual stress by neutron diffraction — The Open University / University of Manchester, 2005
- Residual stress determination by neutron diffraction in powder bed fusion-built Alloy 718: Influence of process parameters and post-treatment — University West, 2020
- Combined experimental–numerical study on residual stresses induced by a single impact as elementary process of mechanical peening — Helmholtz-Zentrum Geesthacht, 2020
- Shot-peening of steam turbine blades: Residual stresses and their modification by fatigue cycling — Nelson Mandela Metropolitan University, 2010
- Effect of Shot Peening on Low Cycle Fatigue Life of Compressor Disc of a Typical Fighter Class Aero-Engine — Regional Centre for Military Airworthiness, 2013
- Method for evaluating shot peening strengthening effect on turbine disc — AECC Beijing Institute of Aeronautical Materials, 2020
- Method for evaluating shot peening strengthening effect on turbine disc — AECC Beijing Institute of Aeronautical Materials, 2022
- Residual stress analysis method and system for shot peening considering the influence of prior processing — Xi'an Jiaotong University, 2025
- System and method for predicting distortion of workpieces due to shot peening machining process — Boeing Company, 2019
- Residual Stress Distribution Analysis in Advanced Materials by Neutron Diffraction: The Case of Spherical Storage Tank Butt Weld — Nuclear Physics Institute ASCR, 2019
- A Discrete-Finite Element Analysis Model Based on Almen Intensity Test for Evaluation of Real Shot Peening Residual Stress — Cheongju University, 2023
- Impact of Shot-Peening on a Single Crystal Nickel-Based Superalloy — Université de Technologie de Troyes, 2014
- WIPO — World Intellectual Property Organization: Global Patent Database
- NIST — National Institute of Standards and Technology: Neutron Residual Stress Measurement
- EPRI — Electric Power Research Institute: Steam Turbine Component Integrity
- Argonne National Laboratory Advanced Photon Source: Synchrotron X-ray Diffraction for Residual Stress
All data and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform.
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