The emerging field of material-based data science requires information-rich databases to generate... more The emerging field of material-based data science requires information-rich databases to generate useful results which are currently sparse in the stress engineering domain. To this end, this study uses the’materials-aware’ text-mining toolkit, ChemDataExtractor, to auto-generate databases of yield-strength and grain-size values by extracting such information from the literature. The precision of the extracted data is 83.0% for yield strength and 78.8% for grain size. The automatically-extracted data were organised into four databases: a Yield Strength, Grain Size, Engineering-Ready Yield Strength and Combined database. For further validation of the databases, the Combined database was used to plot the Hall-Petch relationship for, the alloy, AZ31, and similar results to the literature were found, demonstrating how one can make use of these automatically-extracted datasets.
A neutron diffraction study of deformation in a cast uranium has been conducted for the first tim... more A neutron diffraction study of deformation in a cast uranium has been conducted for the first time. Lattice-scale plasticity in this coarse-grained material initiates at a lower stress than in a previous study of fine-grained material in the literature. This is attributed to a combination of larger thermal residual stresses in the coarse-grained material and the Hall-Petch effect making twinning easier in large grains. Asymmetry between the tensile and compressive response shows that twinning is the dominant plastic deformation mechanism at low strains. Axial texture changes for the cast uranium were calculated by post processing of the full diffraction spectra, which shows that lattice rotations associated with twinning occurred at yield. This lattice rotation was observed to disappear after unloading, which indicates that de-twinning can occur in uranium.
High energy welding technologies, such as electron beam, have a number of potential benefits incl... more High energy welding technologies, such as electron beam, have a number of potential benefits including: faster process time, smaller heat affected zone and potentially favourable weld residual stresses. Therefore, they are good candidates for manufacturing complex components for the next generation of nuclear power plants. However, before electron beam can be deployed on a wide scale, further work is required in a number of areas, including how these welds are treated in structural integrity assessments. As an example, the full extent of the effects of complex residual stress (RS) fields, arising from high energy welding technology, on the fracture behaviour of components has not been fully investigated. This understanding is essential for defect tolerance calculations using integrity assessment procedures. In this study, the fracture toughness of austenitic stainless steel 316L plates with various thicknesses (6mm to 25mm), joined by electron beam welding, is evaluated. Residual st...
In situneutron diffraction method has been used to investigate deformation mechanisms (slip and t... more In situneutron diffraction method has been used to investigate deformation mechanisms (slip and twinning deformation modes) during uniaxial tensile tests of extruded a-titanium alloy at room temperature, 100 and 300 °C. For this purpose, the prediction of an Elasto-Plastic Self-Consistent (EPSC) model was compared with the experimental data. Results show that there is a good agreement between the simulations and neutron diffraction measurements. The EPSC model enables realistic predictions of not only the elastic lattice strains developed in variously oriented grain families but also the macroscopic stress-strain response within the bulk material.
HIGHLIGHTS • A loading frame was designed to simulate bearing overloads on the ENGIN-X strain dif... more HIGHLIGHTS • A loading frame was designed to simulate bearing overloads on the ENGIN-X strain diffractometer at ISIS neutron source, UK. • Neutron transmission imaging was used to map a Bragg edge fitting parameter, associated with material yielding. • It was demonstrated that bearing overloads generate regions of subsurface plasticity in overloaded roller bearings. • Subsurface deformation, observed during roller bearing overload events, appears to reduce the bearings life expectancy.
Internal stresses in materials have a considerable effect on material properties including streng... more Internal stresses in materials have a considerable effect on material properties including strength, fracture toughness, and fatigue resistance. The ENGIN-X beamline is an engineering science facility at ISIS optimized for the measurement of strain and stress using the atomic lattice planes as a strain gauge. Nowadays, the rapidly rising interest in the mechanical properties of engineering materials at low temperatures has been stimulated by the dynamic development of the cryogenic industry and the advanced applications of the superconductor technology. Here we present the design and discuss the test results of a new cryogenic sample environment system for neutron scattering measurements of internal stresses in engineering materials under a load of up to 100 kN and in the temperature range of 6 K to 300 K. Complete cooling of the system starting from the room temperature down to the base temperature takes around 90 min. Understanding of internal stresses in engineering materials at cryogenic temperatures is vital for the modelling and designing of cutting-edge superconducting magnets and other superconductor based applications.
Abstract Neutron and high-energy X-ray diffraction methods have been used to investigate deformat... more Abstract Neutron and high-energy X-ray diffraction methods have been used to investigate deformation mechanisms (slip and twinning activities) during uniaxial tensile tests of Grade 1 commercially pure titanium (Ti-α). These two diffraction techniques have provided valuable and complementary information. The predictions made by an Elasto-Plastic Self-Consistent (EPSC) model, taking into account grain reorientation and stress relaxation induced by twinning activity, have been compared with the experimental data. Results clearly demonstrate that there is a good agreement between simulations and diffraction measurements. The EPSC model enables accurate predictions of: (i) the lattice strains developed in variously oriented {hk.l} grain families within the bulk material, (ii) the grain reorientation induced by twinning activity and (iii) the macroscopic stress-strain response. Two different textured products were studied in order to evaluate the influence of texture on the mesoscopic and macroscopic responses of Ti-α alloy.
Uniaxial samples have been manufactured for tension/compression testing from 316L stainless steel... more Uniaxial samples have been manufactured for tension/compression testing from 316L stainless steel by laser powder bed fusion (LPBF). Samples manufactured by LPBF are known to contain high levels of residual stresses. These uniaxial samples were built from a solid cylindrical rod and subsequently machined to reduce the central cross section of the sample to the required gauge diameter and improve the surface finish. Finite element (FE) models have been developed to simulate the LPBF process of the rods, their removal from the build plate and subsequent machining into the tension/compression samples. High tensile residual stresses were predicted at the surface of the samples, balances by similar magnitude compressive stresses along their axis. Post machining however, these stresses were reduced by around 80% or more. Residual stress measurements were performed on the samples post machining using the neutron diffraction techniques. These measurements confirmed that negligible residual ...
This proposal, that is part of the Bristol-Open University-ISIS long term programme, is to undert... more This proposal, that is part of the Bristol-Open University-ISIS long term programme, is to undertake a series of neutron diffraction experiments to gain an understanding of the interaction between the applied and residual stresses in pre-cracked samples extracted from plates of Type 316 stainless steel welded to P91 ferritic steel.This proposal is an integral part of Indo-UK collaborative project funded by EPSRC called ?DMW-Creep?. One objective in this EPSRC project is to understand the underlying mechanics and physics of creep failure occurring at and near to the weld interface between two metals.
High manganese steels are promising candidates for applications in cryogenic environments. In thi... more High manganese steels are promising candidates for applications in cryogenic environments. In this study, we investigate the mechanical and microstructural responses of a high manganese twinning induced plasticity (TWIP) steel at a low-temperature range (from 373 to 77 K) via in situ neutron diffraction qualification and correlative microscopy characterization. During plastic deformation, stacking fault probability and dislocation density increased at a faster rate at a lower temperature, hence, higher dislocation density and denser mechanical twins were observed, confirmed by microscopic observation. Stacking fault energy was estimated, dropping linearly from 34.8 mJm-2 at 373 K to 17.2 mJm-2 at 77 K. A small amount of austenite transferred to martensite when deforming at 77 K. The contributions to flow stress from solutes, grain boundary, dislocation, and twinning were determined at different temperatures, which shows that the high work strain hardening capacity of the TWIP steel originates from the synergetic strengthening effects of dislocations and twin-twin networks. These findings reveal the relationship among stacking fault energy, microstructure, and deformation mechanisms at the low-temperature range, paving a way in designing TWIP steels with the superb mechanical performance for cryogenic applications.
In situ neutron diffraction and synchrotron X-ray diffraction, combined with image correlation an... more In situ neutron diffraction and synchrotron X-ray diffraction, combined with image correlation analysis of 2D optical and 3D X-ray tomography datasets, have been used to investigate the relationship between elastic lattice strain and total strain during deformation of Gilsocarbon (IM1-24) polygranular nuclear grade graphite. The specimens were flat-end Brazilian discs under diametral loading, such that a compressive-tensile biaxial stress state was developed in the central region. The X-ray study was at ambient temperature, and the neutron diffraction was conducted at temperatures from ambient to 850°C. When under compression, there is a temperature-insensitive linear relationship between the total strain and the lattice strain that is measured perpendicular to the graphite basal planes. However, when under tensile stress, the total strain and elastic strain relationship is temperature sensitive: below 600°C, the lattice tensile strain saturates with increasing total tensile strain; above 600°C, significantly higher tensile lattice strains are sustained. The saturation in tensile lattice strain is attributed to microcracking in the graphite microstructure. Improved resistance to microcracking and damage tolerance at elevated temperature explains the increase in tensile strength of polygranular graphite.
Neutron diffraction and synchrotron X-ray diffraction and imaging have been applied to study, in ... more Neutron diffraction and synchrotron X-ray diffraction and imaging have been applied to study, in situ, the mechanical response to tensile and bending loading of polygranular Gilsocarbon nuclear grade nearisotropic graphite (grade IM1-24). Digital image correlation of X-ray radiographs and digital volume correlation of tomographs allow measurement of bulk elastic moduli and examination of the heterogeneity of deformation in the microstructure. Both the neutron and X-ray studies show the application of tensile strain reduces the bulk elastic modulus. A permanent set is observed to develop with applied tensile strain. The elastic strains within the graphite crystals were measured by diffraction; a crosscorrelation analysis method has been applied for greater speed, robustness and improved precision in the measurement of the change in basal plane separation distance. In compression, a linear relation is observed between the elastic strains in the graphite crystals and the applied strain. In tension, this relationship is non-linear. The results are discussed with respect to the distribution of elastic and inelastic strain within the graphite microstructure. It is deduced that the significant residual elastic strains in the as-manufactured graphite are relaxed by microcracking as tensile strain is applied.
Phase transition and ordering behavior of ternary Ti-Al-Mo alloys using in-situ neutron diffracti... more Phase transition and ordering behavior of ternary Ti-Al-Mo alloys using in-situ neutron diffraction Dedicated to Prof. F. D. Fischer on the occasion of his 70 th birthday Neutron diffraction has been used for in-situ investigations to elucidate the phase transformation behavior of two Mo-containing TiAl alloys with compositions of Ti-44Al-3Mo and Ti-44Al-7Mo (in at.%). Five different phases are present in these alloys. These include three ordered phases at room temperature, namely a 2 , b 0 and c and two disordered phases, a and b, which occur at higher temperatures. The sequence of the three phase transformations in each alloy has been determined. The phase transformation and disordering/ordering temperatures were determined on heating and cooling from the diffracted peak intensities. The neutron experiments are particularly sensitive to the order-disorder transitions in TiAl alloys, which are compared with the overall phase fractions obtained from previous high energy X-ray diffraction. Hysteresis and undercooling effects are observed for the various phase transformations and depend on the nature of atomic rearrangements.
Related Articles Reduced threading dislocation densities in high-T/N-rich grown InN films by plas... more Related Articles Reduced threading dislocation densities in high-T/N-rich grown InN films by plasma-assisted molecular beam epitaxy Appl. Phys. Lett. 102, 051916 (2013) The source of the threading dislocation in GaSb/GaAs hetero-structures and their propagation mechanism Appl. Phys. Lett. 102, 052102 (2013) Critical-temperature/Peierls-stress dependent size effects in body centered cubic nanopillars Appl. Phys. Lett. 102, 041910 (2013) Planar defects, dislocations, and coherently scattering-size in GdBa2Cu3O7−x high-Tc thin films determined by high resolution X-ray diffraction J. Appl. Phys. 113, 033903 (2013) Critical shell thickness for InAs-AlxIn1−xAs(P) core-shell nanowires
To improve the fatigue life of components subject to loads with high surface strain gradients, it... more To improve the fatigue life of components subject to loads with high surface strain gradients, it is possible to coat them with an alloy of higher durability. The present study focuses on the effect of cladding high value track components, made of a standard rail steel UIC 900A/grade 260, with a layer of a premium martensitic stainless steel to reduce wear and fatigue. The laser cladding process inevitably generates residual stresses in the clad and parent metal, which could be detrimental to the integrity of the component. Therefore, measurements to determine the residual stress state of cladded rail were performed using semi-destructive centre-hole and deep hole drilling and non-destructive neutron diffraction techniques. Subsequently, the effects of cycling loading and wear, representative of typical service loads, on the redistribution of the residual stress field were investigated. It was observed that laser cladding causes a triaxial compressive residual stress field in the clad and near the interface and a tensile stress field in the parent material. The stress field is shown to change when the first cycle of load is applied but reaches a steady state after only 10 cycles: After the 10th cycle there is no evidence that the clad continues accumulating strain which could indicate that there is low risk of ratcheting. Wear effect on residual stress redistribution was found to be local on the surface of the specimen only.
The emerging field of material-based data science requires information-rich databases to generate... more The emerging field of material-based data science requires information-rich databases to generate useful results which are currently sparse in the stress engineering domain. To this end, this study uses the’materials-aware’ text-mining toolkit, ChemDataExtractor, to auto-generate databases of yield-strength and grain-size values by extracting such information from the literature. The precision of the extracted data is 83.0% for yield strength and 78.8% for grain size. The automatically-extracted data were organised into four databases: a Yield Strength, Grain Size, Engineering-Ready Yield Strength and Combined database. For further validation of the databases, the Combined database was used to plot the Hall-Petch relationship for, the alloy, AZ31, and similar results to the literature were found, demonstrating how one can make use of these automatically-extracted datasets.
A neutron diffraction study of deformation in a cast uranium has been conducted for the first tim... more A neutron diffraction study of deformation in a cast uranium has been conducted for the first time. Lattice-scale plasticity in this coarse-grained material initiates at a lower stress than in a previous study of fine-grained material in the literature. This is attributed to a combination of larger thermal residual stresses in the coarse-grained material and the Hall-Petch effect making twinning easier in large grains. Asymmetry between the tensile and compressive response shows that twinning is the dominant plastic deformation mechanism at low strains. Axial texture changes for the cast uranium were calculated by post processing of the full diffraction spectra, which shows that lattice rotations associated with twinning occurred at yield. This lattice rotation was observed to disappear after unloading, which indicates that de-twinning can occur in uranium.
High energy welding technologies, such as electron beam, have a number of potential benefits incl... more High energy welding technologies, such as electron beam, have a number of potential benefits including: faster process time, smaller heat affected zone and potentially favourable weld residual stresses. Therefore, they are good candidates for manufacturing complex components for the next generation of nuclear power plants. However, before electron beam can be deployed on a wide scale, further work is required in a number of areas, including how these welds are treated in structural integrity assessments. As an example, the full extent of the effects of complex residual stress (RS) fields, arising from high energy welding technology, on the fracture behaviour of components has not been fully investigated. This understanding is essential for defect tolerance calculations using integrity assessment procedures. In this study, the fracture toughness of austenitic stainless steel 316L plates with various thicknesses (6mm to 25mm), joined by electron beam welding, is evaluated. Residual st...
In situneutron diffraction method has been used to investigate deformation mechanisms (slip and t... more In situneutron diffraction method has been used to investigate deformation mechanisms (slip and twinning deformation modes) during uniaxial tensile tests of extruded a-titanium alloy at room temperature, 100 and 300 °C. For this purpose, the prediction of an Elasto-Plastic Self-Consistent (EPSC) model was compared with the experimental data. Results show that there is a good agreement between the simulations and neutron diffraction measurements. The EPSC model enables realistic predictions of not only the elastic lattice strains developed in variously oriented grain families but also the macroscopic stress-strain response within the bulk material.
HIGHLIGHTS • A loading frame was designed to simulate bearing overloads on the ENGIN-X strain dif... more HIGHLIGHTS • A loading frame was designed to simulate bearing overloads on the ENGIN-X strain diffractometer at ISIS neutron source, UK. • Neutron transmission imaging was used to map a Bragg edge fitting parameter, associated with material yielding. • It was demonstrated that bearing overloads generate regions of subsurface plasticity in overloaded roller bearings. • Subsurface deformation, observed during roller bearing overload events, appears to reduce the bearings life expectancy.
Internal stresses in materials have a considerable effect on material properties including streng... more Internal stresses in materials have a considerable effect on material properties including strength, fracture toughness, and fatigue resistance. The ENGIN-X beamline is an engineering science facility at ISIS optimized for the measurement of strain and stress using the atomic lattice planes as a strain gauge. Nowadays, the rapidly rising interest in the mechanical properties of engineering materials at low temperatures has been stimulated by the dynamic development of the cryogenic industry and the advanced applications of the superconductor technology. Here we present the design and discuss the test results of a new cryogenic sample environment system for neutron scattering measurements of internal stresses in engineering materials under a load of up to 100 kN and in the temperature range of 6 K to 300 K. Complete cooling of the system starting from the room temperature down to the base temperature takes around 90 min. Understanding of internal stresses in engineering materials at cryogenic temperatures is vital for the modelling and designing of cutting-edge superconducting magnets and other superconductor based applications.
Abstract Neutron and high-energy X-ray diffraction methods have been used to investigate deformat... more Abstract Neutron and high-energy X-ray diffraction methods have been used to investigate deformation mechanisms (slip and twinning activities) during uniaxial tensile tests of Grade 1 commercially pure titanium (Ti-α). These two diffraction techniques have provided valuable and complementary information. The predictions made by an Elasto-Plastic Self-Consistent (EPSC) model, taking into account grain reorientation and stress relaxation induced by twinning activity, have been compared with the experimental data. Results clearly demonstrate that there is a good agreement between simulations and diffraction measurements. The EPSC model enables accurate predictions of: (i) the lattice strains developed in variously oriented {hk.l} grain families within the bulk material, (ii) the grain reorientation induced by twinning activity and (iii) the macroscopic stress-strain response. Two different textured products were studied in order to evaluate the influence of texture on the mesoscopic and macroscopic responses of Ti-α alloy.
Uniaxial samples have been manufactured for tension/compression testing from 316L stainless steel... more Uniaxial samples have been manufactured for tension/compression testing from 316L stainless steel by laser powder bed fusion (LPBF). Samples manufactured by LPBF are known to contain high levels of residual stresses. These uniaxial samples were built from a solid cylindrical rod and subsequently machined to reduce the central cross section of the sample to the required gauge diameter and improve the surface finish. Finite element (FE) models have been developed to simulate the LPBF process of the rods, their removal from the build plate and subsequent machining into the tension/compression samples. High tensile residual stresses were predicted at the surface of the samples, balances by similar magnitude compressive stresses along their axis. Post machining however, these stresses were reduced by around 80% or more. Residual stress measurements were performed on the samples post machining using the neutron diffraction techniques. These measurements confirmed that negligible residual ...
This proposal, that is part of the Bristol-Open University-ISIS long term programme, is to undert... more This proposal, that is part of the Bristol-Open University-ISIS long term programme, is to undertake a series of neutron diffraction experiments to gain an understanding of the interaction between the applied and residual stresses in pre-cracked samples extracted from plates of Type 316 stainless steel welded to P91 ferritic steel.This proposal is an integral part of Indo-UK collaborative project funded by EPSRC called ?DMW-Creep?. One objective in this EPSRC project is to understand the underlying mechanics and physics of creep failure occurring at and near to the weld interface between two metals.
High manganese steels are promising candidates for applications in cryogenic environments. In thi... more High manganese steels are promising candidates for applications in cryogenic environments. In this study, we investigate the mechanical and microstructural responses of a high manganese twinning induced plasticity (TWIP) steel at a low-temperature range (from 373 to 77 K) via in situ neutron diffraction qualification and correlative microscopy characterization. During plastic deformation, stacking fault probability and dislocation density increased at a faster rate at a lower temperature, hence, higher dislocation density and denser mechanical twins were observed, confirmed by microscopic observation. Stacking fault energy was estimated, dropping linearly from 34.8 mJm-2 at 373 K to 17.2 mJm-2 at 77 K. A small amount of austenite transferred to martensite when deforming at 77 K. The contributions to flow stress from solutes, grain boundary, dislocation, and twinning were determined at different temperatures, which shows that the high work strain hardening capacity of the TWIP steel originates from the synergetic strengthening effects of dislocations and twin-twin networks. These findings reveal the relationship among stacking fault energy, microstructure, and deformation mechanisms at the low-temperature range, paving a way in designing TWIP steels with the superb mechanical performance for cryogenic applications.
In situ neutron diffraction and synchrotron X-ray diffraction, combined with image correlation an... more In situ neutron diffraction and synchrotron X-ray diffraction, combined with image correlation analysis of 2D optical and 3D X-ray tomography datasets, have been used to investigate the relationship between elastic lattice strain and total strain during deformation of Gilsocarbon (IM1-24) polygranular nuclear grade graphite. The specimens were flat-end Brazilian discs under diametral loading, such that a compressive-tensile biaxial stress state was developed in the central region. The X-ray study was at ambient temperature, and the neutron diffraction was conducted at temperatures from ambient to 850°C. When under compression, there is a temperature-insensitive linear relationship between the total strain and the lattice strain that is measured perpendicular to the graphite basal planes. However, when under tensile stress, the total strain and elastic strain relationship is temperature sensitive: below 600°C, the lattice tensile strain saturates with increasing total tensile strain; above 600°C, significantly higher tensile lattice strains are sustained. The saturation in tensile lattice strain is attributed to microcracking in the graphite microstructure. Improved resistance to microcracking and damage tolerance at elevated temperature explains the increase in tensile strength of polygranular graphite.
Neutron diffraction and synchrotron X-ray diffraction and imaging have been applied to study, in ... more Neutron diffraction and synchrotron X-ray diffraction and imaging have been applied to study, in situ, the mechanical response to tensile and bending loading of polygranular Gilsocarbon nuclear grade nearisotropic graphite (grade IM1-24). Digital image correlation of X-ray radiographs and digital volume correlation of tomographs allow measurement of bulk elastic moduli and examination of the heterogeneity of deformation in the microstructure. Both the neutron and X-ray studies show the application of tensile strain reduces the bulk elastic modulus. A permanent set is observed to develop with applied tensile strain. The elastic strains within the graphite crystals were measured by diffraction; a crosscorrelation analysis method has been applied for greater speed, robustness and improved precision in the measurement of the change in basal plane separation distance. In compression, a linear relation is observed between the elastic strains in the graphite crystals and the applied strain. In tension, this relationship is non-linear. The results are discussed with respect to the distribution of elastic and inelastic strain within the graphite microstructure. It is deduced that the significant residual elastic strains in the as-manufactured graphite are relaxed by microcracking as tensile strain is applied.
Phase transition and ordering behavior of ternary Ti-Al-Mo alloys using in-situ neutron diffracti... more Phase transition and ordering behavior of ternary Ti-Al-Mo alloys using in-situ neutron diffraction Dedicated to Prof. F. D. Fischer on the occasion of his 70 th birthday Neutron diffraction has been used for in-situ investigations to elucidate the phase transformation behavior of two Mo-containing TiAl alloys with compositions of Ti-44Al-3Mo and Ti-44Al-7Mo (in at.%). Five different phases are present in these alloys. These include three ordered phases at room temperature, namely a 2 , b 0 and c and two disordered phases, a and b, which occur at higher temperatures. The sequence of the three phase transformations in each alloy has been determined. The phase transformation and disordering/ordering temperatures were determined on heating and cooling from the diffracted peak intensities. The neutron experiments are particularly sensitive to the order-disorder transitions in TiAl alloys, which are compared with the overall phase fractions obtained from previous high energy X-ray diffraction. Hysteresis and undercooling effects are observed for the various phase transformations and depend on the nature of atomic rearrangements.
Related Articles Reduced threading dislocation densities in high-T/N-rich grown InN films by plas... more Related Articles Reduced threading dislocation densities in high-T/N-rich grown InN films by plasma-assisted molecular beam epitaxy Appl. Phys. Lett. 102, 051916 (2013) The source of the threading dislocation in GaSb/GaAs hetero-structures and their propagation mechanism Appl. Phys. Lett. 102, 052102 (2013) Critical-temperature/Peierls-stress dependent size effects in body centered cubic nanopillars Appl. Phys. Lett. 102, 041910 (2013) Planar defects, dislocations, and coherently scattering-size in GdBa2Cu3O7−x high-Tc thin films determined by high resolution X-ray diffraction J. Appl. Phys. 113, 033903 (2013) Critical shell thickness for InAs-AlxIn1−xAs(P) core-shell nanowires
To improve the fatigue life of components subject to loads with high surface strain gradients, it... more To improve the fatigue life of components subject to loads with high surface strain gradients, it is possible to coat them with an alloy of higher durability. The present study focuses on the effect of cladding high value track components, made of a standard rail steel UIC 900A/grade 260, with a layer of a premium martensitic stainless steel to reduce wear and fatigue. The laser cladding process inevitably generates residual stresses in the clad and parent metal, which could be detrimental to the integrity of the component. Therefore, measurements to determine the residual stress state of cladded rail were performed using semi-destructive centre-hole and deep hole drilling and non-destructive neutron diffraction techniques. Subsequently, the effects of cycling loading and wear, representative of typical service loads, on the redistribution of the residual stress field were investigated. It was observed that laser cladding causes a triaxial compressive residual stress field in the clad and near the interface and a tensile stress field in the parent material. The stress field is shown to change when the first cycle of load is applied but reaches a steady state after only 10 cycles: After the 10th cycle there is no evidence that the clad continues accumulating strain which could indicate that there is low risk of ratcheting. Wear effect on residual stress redistribution was found to be local on the surface of the specimen only.
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