Assessment of microstructures and mechanical behaviour of metallic materials through non-destructive characterisation
TL;DR: In this paper, the authors discuss the progress made in the application of non-destructive testing (NDT) techniques in evaluating various microstructural features and mechanical properties with emphasis on recent studies.
Abstract: Non-destructive evaluation (NDE) of materials for characterising various key microstructural features, mechanical properties (tension, creep, fatigue crack growth, hardness and fracture toughness), deformation and damage mechanisms has attracted considerable attention in the past 20 years as a primary step towards ensuring structural integrity of components. However, until recently, the correlations between the various NDE parameters and material properties have been only empirical and based on physical principles. The interaction between the NDE probing medium and the mechanical behaviour is not yet fully understood. The purpose of this review is to discuss the progress made in the application of non-destructive testing (NDT) techniques in evaluating various microstructural features and mechanical properties with emphasis on recent studies. Reinterpretation of older data, in the light of present understanding of the interaction of the NDE probing medium with material parameters, is carried out selectively. The NDT techniques evaluated include acoustic emission, ultrasonic attenuation and velocity, magnetic hysteresis parameters, magnetic Barkhausen emission, acoustic Barkhausen emission, laser interferometry, positron annihilation, X-ray diffraction and small angle neutron scattering. Critical assessments of the applicability of the various NDE techniques for the material parameters are provided.
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TL;DR: In this paper, the effect of initial pH and temperature of iron salt solutions on formation of magnetite (Fe3O4) nanoparticles during co-precipitation was reported.
287 citations
TL;DR: A critical review of the main results obtained to date in the secondary and tertiary stages of creep is presented in this article, and the advantages and disadvantages of each method are discussed.
Abstract: The assessment of creep damage in steels employed in the power generation industry is usually carried out by means of replica metallography, but the several shortcomings of this method have prompted a search for alternative or complementary non-destructive techniques, ranging from ultrasonic to electromagnetic methods, hardness measurements and nuclear techniques. A critical review of the main results obtained to date in the secondary and tertiary stages of creep is presented in this paper, and the advantages and disadvantages of each method are discussed. Ultrasonic and potential drop techniques appear to be the most promising, but further research is needed before they are fully mature for deployment in the field.
183 citations
20 Aug 2008-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the elastic modulus of near β and β titanium alloys was measured by nano-indentation and ultrasonic techniques, and the data obtained from both the experiments were analyzed and compared with each other.
Abstract: The elastic modulus of near β and β titanium alloys was measured by nano-indentation and ultrasonic techniques The data obtained from both the experiments were analyzed and compared with each other The effects of composition and heat treatment on elastic modulus of the material are discussed The elastic modulus of β Ti–35Nb–57Ta–72Zr (TNTZ) was found to be half of the elastic modulus of the titanium Near β Ti–13Zr–13Nb (TZN) alloy hot worked at 800 °C and solution treated at 800 °C followed by water quenching also showed low elastic modulus value The accuracy of these two elastic modulus measurement techniques is discussed in terms of microstructures
146 citations
TL;DR: In this article, a nonlinear domain (second harmonic amplitude) was used to evaluate the second harmonic amplitude (SHA) of a titanium alloy for in-service evaluation of creep damage.
93 citations
TL;DR: In this paper, the authors review the present state of understanding of the Barkhausen effect in soft ferromagnetic materials and present a complete and consistent picture emerges thanks to an exactly solvable model of avalanche dynamics, known as the ABBM model, which ultimately describes the system in terms of a Langevin equation for the velocity of the avalanche front.
Abstract: We review the present state of understanding of the Barkhausen effect in soft ferromagnetic materials. Barkhausen noise (BN) is generated by the discontinuous motion of magnetic domains as they interact with impurities and defects. BN is one of the many examples of crackling noise, arising in a variety of contexts with remarkably similar features, and occurring when a system responds in a jerky manner to a smooth external forcing. Among all crackling system, we focus on BN, where a complete and consistent picture emerges thanks to an exactly solvable model of avalanche dynamics, known as the ABBM model, which ultimately describes the system in terms of a Langevin equation for the velocity of the avalanche front. Despite its simplicity, the ABBM model is able to accurately reproduce the phenomenology observed in the experiments on a large class of magnetic materials, as long as universal properties are involved. To complete the picture and to understand the long-standing discrepancy between the ABBM theory...
81 citations
References
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Book•
01 Jun 1972
TL;DR: In this paper, the authors present materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
Abstract: Introduction to Magnetic Materials, 2nd Edition covers the basics of magnetic quantities, magnetic devices, and materials used in practice. While retaining much of the original, this revision now covers SQUID and alternating gradient magnetometers, magnetic force microscope, Kerr effect, amorphous alloys, rare-earth magnets, SI Units alongside cgs units, and other up-to-date topics. In addition, the authors have added an entirely new chapter on information materials. The text presents materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
6,573 citations
Book•
24 Aug 1987
TL;DR: In this paper, the authors proposed a method to measure residual stress from X-ray diffraction data. But, their method is not suitable for the analysis of nonlinear elasticity theory.
Abstract: 1 Introduction.- 1.1 The Origin of Stresses.- 1.2 Methods of Measuring Residual Stresses.- 1.3 Some Examples of Residual Stresses.- References.- 2 Fundamental Concepts in Stress Analysis.- 2.1 Introduction.- 2.2 Definitions.- 2.3 Stress and Strain.- 2.4 Forces and Stresses.- 2.5 Displacements and Strains.- 2.6 Transformation of Axes and Tensor Notation.- 2.7 Elastic Stress-Strain Relations for Isotropic Materials.- 2.8 Structure of Single Crystals.- 2.9 Elastic Stress-Strain Relations in Single Crystals.- 2.10 Equations of Equilibrium.- 2.11 Conditions of Compatibility.- 2.12 Basic Definitions in Plastic Deformation.- 2.13 Plastic Deformation of Single Crystals.- 2.14 Deformation and Yielding in Inhomogeneous Materials.- Problems.- 3 Analysis of Residual Stress Fields Using Linear Elasticity Theory.- 3.1 Introduction.- 3.2 Macroresidual Stresses.- 3.3 Equations of Equilibrium for Macrostresses.- 3.4 Microstresses.- 3.5 Equations of Equilibrium for Micro- and Pseudo-Macrostresses.- 3.6 Calculation of Micro- and PM Stresses.- 3.7 The Total Stress State in Surface Deformed Multiphase Materials.- 3.8 Macroscopic Averages of Single Crystal Elastic Constants.- 3.9 The Voigt Average.- 3.10 The Reuss Average.- 3.11 Other Approaches to Elastic Constant Determination.- 3.12 Average Diffraction Elastic Constants.- Summary.- References.- 4 Fundamental Concepts in X-ray Diffraction.- 4.1 Introduction.- 4.2 Fundamentals of X-rays.- 4.3 Short-wavelength Limit and the Continuous Spectrum.- 4.4 Characteristic Radiation Lines.- 4.5 X-ray Sources.- 4.6 Absorption of X-rays.- 4.7 Filtering of X-rays.- 4.8 Scattering of X-rays.- 4.9 Scattering from Planes of Atoms.- 4.10 The Structure Factor of a Unit Cell.- 4.11 Experimental Utilization of Bragg's Law.- 4.12 Monochromators.- 4.13 Collimators and Slits.- 4.14 Diffraction Patterns from Single Crystals.- 4.15 Diffraction Patterns from Polycrystalline Specimens.- 4.16 Basic Diffractometer Geometry.- 4.17 Intensity of Diffracted Lines for Polycrystals.- 4.18 Multiplicity.- 4.19 Lorentz Factor.- 4.20 Absorption Factor.- 4.21 Temperature Factor.- 4.22 X-ray Detectors.- 4.23 Deadtime Correction for Detection Systems.- 4.24 Total Diffracted Intensity at a Given Angle 20.- 4.25 Depth of Penetration of X-rays.- 4.26 Fundamental Concepts in Neutron Diffraction.- 4.27 Scattering and Absorption of Neutrons.- Problems.- Bibliography and References.- 5 Determination of Strain and Stress Fields by Diffraction Methods.- 5.1 Introduction.- 5.2 Fundamental Equations of X-ray Strain Determination.- 5.3 Analysis of Regular "d" vs. sin2? Data.- 5.4 Determination of Stresses from Diffraction Data.- 5.5 Biaxial Stress Analysis.- 5.6 Triaxial Stress Analysis.- 5.7 Determination of the Unstressed Lattice Spacing.- 5.8 Effect of Homogeneity of the Strain Distribution and Specimen Anisotropy.- 5.9 Average Strain Data from Single Crystal Specimens.- 5.10 Interpretation of the Average X-ray Strain Data Measured from Polycrystalline Specimens.- 5.11 Interpretation of Average Stress States in Polycrystalline Specimens.- 5.12 Effect of Stress Gradients Normal to the Surface on d vs. sin2? Data.- 5.13 Experimental Determination of X-ray Elastic Constants.- 5.14 Determination of Stresses from Oscillatory Data.- 5.15 Stress Measurements with Neutron Diffraction.- 5.16 Effect of Composition Gradients with Depth.- 5.17 X-ray Determination of Yielding.- 5.18 Summary.- Problem.- References.- 6 Experimental Errors Associated with the X-ray Measurement of Residual Stress.- 6.1 Introduction.- 6.2 Selection of the Diffraction Peak for Stress Measurements.- 6.3 Peak Location.- 6.3.1 Half-Value Breadth and Centroid Methods.- 6.3.2 Functional Representations of X-ray Peaks.- 6.3.3 Peak Determination by Fitting a Parabola.- 6.3.4 Determination of Peak Shift.- 6.4 Determination of Peak Position for Asymmetric Peaks.- 6.5 Statistical Errors Associated with the X-ray Measurement of Line Profiles.- 6.6 Statistical Errors in Stress.- 6.6.1 The sin2? Technique.- 6.6.2 Two-Tilt Technique.- 6.6.3 Triaxial Stress Analysis.- 6.6.4 Statistical Errors in X-ray Elastic Constants.- 6.7 Instrumental Errors in Residual Stress Analysis.- 6.7.1 Variation of the Focal Point with ? and ?.- 6.7.2 Effect of Horizontal Divergence on Focusing.- 6.7.3 Effect of Vertical Beam Divergence.- 6.7.4 Effect of Specimen Displacement.- 6.7.5 Effect of ?-axis not Corresponding to the 2?-axis.- 6.7.6 Error Equations for the ?-Goniometer.- 6.7.7 Effect of Errors in the True Zero Position of the ?-axis.- 6.7.8 Alignment Procedures.- 6.8 Corrections for Macrostress Gradients.- 6.9 Corrections for Layer Removal.- 6.10 Summary.- Problems.- References.- 7 The Practical Use of X-ray Techniques.- 7.1 Introduction.- 7.2 The Use of Ordinary Diffractometers.- 7.3 Software and Hardware Requirements.- 7.4 Available Instruments.- 7.5 Selected Applications of a Portable X-ray Residual Stress Unit (By W. P. Evans).- Reference.- 8 The Shape of Diffraction Peaks - X-ray Line Broadening.- 8.1 Introduction.- 8.2 Slit Corrections.- 8.3 Fourier Analysis of Peak Broadening.- Problem.- References.- Appendix A: Solutions to Problems.- Appendix B.- B.1 Introduction.- B.2 The Marion-Cohen Method.- B.3 Dolle-Hauk Method (Oscillation-free Reflections).- B.4 Methods of Peiter and Lode.- B.5 Use of High Multiplicity Peaks.- References.- Appendix C: Fourier Analysis.- Appendix D: Location of Useful Information in "International Tables for Crystallography".- Appendix F: A Compilation of X-ray Elastic Constants (By Dr. M. James).- References.
2,146 citations
01 Jan 1982
TL;DR: The Review of Progress in Quantitative NDE (ROPQN) as mentioned in this paper is the world's leading conference in reporting annually new research and development results in quantitative NDE and promotes communication between the research and engineering communities and emphasize current reporting of work in progress.
Abstract: The Review of Progress in Quantitative NDE is the world's leading conference in reporting annually new research and development results in quantitative NDE. The conference reports on both fundamental and applied advances in NDE and promotes communication between the research and engineering communities and emphasize current reporting of work in progress. Attendees include representatives of academia (including students), industry, and government with approximately one-half coming from the United States and the other half from overseas. This volume represents the best report of ongoing work that is available anywhere. Connections and overlap with the medical diagnostic community are highlighted.
1,989 citations
1,571 citations
TL;DR: In this article, a criterion for the validity of approximate integral equations describing the various field quantities of interest was obtained by employing a ''configurational averaging'' procedure, and the extinction theorem was obtained and given rise to the forward-amplitude theorem of multiple scattering.
Abstract: Multiple scattering effects due to a random array of obstacles are considered. Employing a ``configurational averaging'' procedure, a criterion is obtained for the validity of approximate integral equations describing the various field quantities of interest. The extinction theorem is obtained and shown to give rise to the forward‐amplitude theorem of multiple scattering. In the limit of vanishing correlations in position, the complex propagation constant κ of the scattering medium is obtained. Under appropriate restrictions, the expression for κ is shown to include both the square‐root law of isotropic scatterers and the additive rule for cross sections valid for sufficiently low densities of anisotropic obstacles. Some specific examples from acoustics and electromagnetic theory then indicate that at least in the simplest cases the results remain valid for physically allowable densities of obstacles.
929 citations