Showing papers on "Deformation (engineering) published in 1975"
TL;DR: In this paper, the authors investigated the hypothesis that localization of deformation into a shear band may be considered a result of an instability in the constitutive description of homogeneous deformation.
Abstract: T his paper investigates the hypothesis that localization of deformation into a shear band may be considered a result of an instability in the constitutive description of homogeneous deformation. General conditions for a bifurcation, corresponding to the localization of deformation into a planar band, are derived. Although the analysis is general and applications to other localization phenomena are noted, the constitutive relations which are examined in application of the criterion for localization are intended to model the behavior of brittle rock masses under compressive principal stresses. These relations are strongly pressure-sensitive since inelasticity results from frictional sliding on an array of fissures; the resulting inelastic response is dilatant, owing to uplift in sliding at asperities and to local tensile cracking from fissure tips. The appropriate constitutive descriptions involve non-normality of plastic strain increments to the yield hyper-surface. Also, it is argued that the subsequent yield surfaces will develop a vertex-like structure. Both of these features are shown to be destabilizing and to strongly influence the resulting predictions for localization by comparison to predictions based on classical plasticity idealizations, involving normality and smooth yield surfaces. These results seem widely applicable to discussions of the inception of rupture as a constitutive instability.
2,411 citations
TL;DR: In this paper, a set of constitutive equations has been formulated to represent elastic-viscoplastic strain hardening material behavior for large deformations and arbitrary loading histories, and the total deformation rate is considered to be separable into elastic and inelastic components which are functions of state variables at all stages of loading and unloading.
Abstract: : A set of constitutive equations has been formulated to represent elastic-viscoplastic strain hardening material behavior for large deformations and arbitrary loading histories. An essential feature of the formulation is that the total deformation rate is considered to be separable into elastic and inelastic components which are functions of state variables at all stages of loading and unloading. The theory, therefore, is independent of a yield criterion or loading and unloading conditions. The deformation rate components are determinable from the current state which permits an incremental formulation of problems. Strain hardening is considered in the equations by introducing plastic work as the representative state variable. The problem of uniaxial straining has been examined for a number of histories that included straining at various rates, rapid changes of strain rate, unloading and reloading, and stress relaxation. The calculations were based on material constants chosen to represent commercially pure titanium. The results are in good agreement with corresponding experiments on titanium specimens. (Author)
942 citations
TL;DR: In this article, an Eulerian finite element formulation for large elastic-plastic flow is presented, based on Hill's variational principle for incremental deformations, and is suited to isotropically hardening Prandtl-Reuss materials.
724 citations
Book•
07 Jul 1975
TL;DR: In this article, the authors present a review of Free-Energy Composition Diagrams (FECD) and a comparison with Massive Transformations (MT) for fcc and hcp materials.
Abstract: Introduction Chapter 1 Description of Crystals 1.1 Atom Packing in fcc and hcp Crystals 1.2 The Stereographic Projection Chapter 2 Structure Determination 2.1 X--ray Diffraction 2.2 Transmission Electron Microscope (TEM) 2.3 Scanning Electron Microscope (SEM) Chapter 3 the Plastic Deformation of Metal Crystals 3.1 Slip Systems 3.2 Resolved Shear Stress (Schmidt Factor) 3.3 Single--Crystal Tensile Tests (fcc) 3.4 Relationship to Polycrystalline Deformation 3.5 Theoretical Strength of Metals Chapter 4 Dislocations 4.1 The Edge Dislocation 4.2 The Screw Dislocation 4.3 Mixed Dislocations 4.4 Terminology of "Crooked" Dislocations 4.5 Dislocation Loops 4.6 Mobile Dislocations in Real Crystals 4.7 Observation of Dislocations 4.8 Elastic Strain Energy 4.9 Energy of Dislocations 4.10 Forces upon Dislocations 4.11 The Stress Field Produced by Dislocations 4.12 Line Tension 4.13 Extended Dislocations 4.14 Dislocations in fcc Metals 4.15 Frank--Read Generator 4.16 Interpretation of Plastic Flow in Terms of Dislocation Motion Chapter 5 Vacancies 5.1 Vacancy Formation Chapter 6 Diffusion 6.1 Phenomenological Approach 6.2 Atomistic Approach Chapter 7 Interfaces 7.1 Classification, Geometry, and Energy of Interfaces 7.2 Surface Tension and Surface Free Energy of Interfaces 7.3 The Shape of Grains in Two and Three Dimensions 7.4 Grain--Boundary Segregation 7.5 Motion of Grain Boundaries Chapter 8 Nucleation 8.1 Homogeneous Nucleation 8.2 Heterogeneous Nucleation Chapter 9 Solidification 9.1 Nucleation 9.2 Solidfication of Pure Metals 9.3 Solidification of Alloys 9.4 Solidification of Eutectic Alloys 9.5 Cast Metals Chapter 10 Recovery and Recrystal-- Lization 10.1 Stored Energy 10.2 Release of Stored Energy during Annealing 10.3 Kinetics of Recovery 10.4 Nucleation Mechanisms for Recrystallization 10.5 Kinetics of Recrystallization 10.6 Control of Recrystallization Temperature and Grain Size 10.7 Related Topics Chapter 11 Precipitation from Solid Solutions 11.1 Review of Free--Energy Composition Diagrams 11.2 The Precipitation Transformation 11.3 Nucleation in the Solid State 11.4 Kinetics of Precipitation Reactions 11.5 Precipitation Hardening Chapter 12 Diffusion--Controlled Growth of Equilibrium Precipitates 12.1 Single--Phase Precipitates 12.2 Eutectoid Transformations 12.3 Discontinuous Precipitation Chapter 13 Martensitic Transformations 13.1 Twinning 13.2 Crystallography of Martensitic Transformations 13.3 Some Characteristics of Martensitic Transformations 13.4 Thermodynamics 13.5 Thermoelastic Martensites 13.6 Additional Characteristics of Martensitic Transformations 13.7 Nucleation of Martensite 13.8 Summary and Comparison with Massive Transformations 13.9 Bainite Chapter 14 Some Applications of Physical Metallurgy 14.1 Strengthening Mechanisms 14.2 Strength and Ductility 14.3 The Physical Metallurgy of Some High--Strength Steels Appendix A S.I. Units Index
517 citations
TL;DR: In this paper, the tensile properties of the intermetallic compound TiAl have been determined at several temperatures in the range 25 to 1000°C, and the results indicate that the ductilebrittle transition behavior of TiAl at about 700°C is controlled by the trailinga/6 [112] partial dislocation components of the superdislocations overcoming their pinning barriers.
Abstract: The tensile properties of the intermetallic compound TiAl have been determined at several temperatures in the range 25 to 1000°C. Additional variables studied were the influence of strain rate and the effect of exposure to oxidizing conditions prior to testing. The modes of deformation under the various testing conditions were studied in the electron microscope, the modes of fracture were studied in the scanning electron microscope, and these data were correlated with the mechanical properties. The results indicate that the ductilebrittle transition behavior of TiAl at about 700°C is controlled by the trailinga/6 [112] partial dislocation components of thea [011] superdislocations overcoming their pinning barriers. It was also shown that prior exposure to oxidizing conditions does not markedly influence the mechanical properties of TiAl.
436 citations
Book•
30 Apr 1975
TL;DR: The proceedings of an international symposium held at Pennsylvania State University in July of 1983 as mentioned in this paper emphasized the deformation behavior of crystals and polycrystalline and polyphase ceramics with internationally recognized authorities as keynote lecturers on the major subtopics.
Abstract: In recent years there has been extensive progress in the research on plastic deformation of ceramic materials. This volume constitutes the proceedings of an international symposium held at Pennsylvania State University in July of 1983. It includes studies of semiconductors and minerals which are closely related to ceramic materials. This conference emphasized the deformation behavior of crystals and polycrystalline and polyphase ceramics with internationally recognized authorities as keynote lecturers on the major subtopics. The papers in this volume discuss dislocation dynamics and deformation of single crystals, including binary oxides, ternary oxides, silicates, nonstoichiometric oxides, covalent materials and halides; and the effects of point defects and twinning. Others address deformation of polycrystalline ceramics consider oxides, nonoxides, polyphase materials and superplastic deformation. There are also several papers dealing with cavity nucleation and creep crack growth, representing a major new research thrust in ceramics research.
239 citations
TL;DR: In this article, the compressive flow behavior of polycrystalline aluminium pre-strained by tension was investigated at temperatures between room temperature and 450°C, and the change in dislocation structures during compression was also examined by transmission electron microscopy.
231 citations
TL;DR: In this paper, the mean stress and strain in the matrix of such materials, and for the workhardening caused by the mean stresses are taken into account, and the theoretical hardening rate is less than the observed value, but the theory is demonstrated to have considerable empirical value in predicting the initial hardening rates in dispersionhardened metals, over-aged precipitation-hardened alloys and fibre-reinforced metal composites.
215 citations
TL;DR: In this article, two analytic forms of the strain energy function for isotropic, incompressible materials are suggested, which involve five or nine terms, the coefficients of which are found by regression to the general deformation plot.
Abstract: A plot of principal stress difference versus principal extension ratios has been used as a graphic representation of general deformation. Two analytic forms of the strain energy function for isotropic, incompressible materials are suggested. These involve five or nine terms, the coefficients of which are found by regression to the general deformation plot. The resulting stress–strain equations are used to predict particular deformations, for example, simple extension, and are also evaluated in model engineering desing experiments. These experiments use interative techniques to predict the shapes and pressures of inflated diaphragms and tubes, and it is shown that the equations lead to accurate results even at relatively high extensions.
194 citations
TL;DR: In this paper, the microstructure of the strongly deformed compound wires as functions of the degree of deformation and the fibre diameter were discussed. But the authors did not consider the effect of the diameter of the fibres.
167 citations
TL;DR: In this paper, a review of tensile strength of agglomerates is given, with a discussion of the most important theoretical considerations, various methods of measurement, a comparison of measuring techniques by experimental results and a brief look at deformation behavior under unidirectional loading.
TL;DR: In this paper, the shape of the log stress-log strain rate curve for the Al-33 wt pct Cu eutectic alloy was examined and the inherent grain growth of the very fine grains which occurs during deformation, and the strain dependence of m at low strains, were shown to be the causes of the familiar shape of log stresslog strain curve for Al-Cu alloy.
Abstract: The usual method of measuring the strain rate sensitive ‘m’ values of superplastic materials through differential cross-head speed is found to result in improperly definedm values;m is found to depend strongly on the strain to which the material is subjected, especially at low strains. In this connection, the shape of the log stress-log strain rate curve is examined for the Al-33 wt pct Cu eutectic alloy. The inherent grain growth of the very fine grains which occurs during deformation, and the strain dependence ofm at low strains, are shown to be the causes of the familiarS shape of the log stress-log strain rate curves for the Al-Cu alloy. At high strains (15 to 20 pct and higher) where the stress is no longer importantly strain sensitive, the log stress-log strain rate curve is a straight line of slope near 0.5. The elongation at fracture also does not go through a maximum but continues to increase slowly to the lowest strain rate examined: 10-7 per s.
TL;DR: In this paper, the compressive flow behavior of Al, Al−7 pct Mg and 7075 Al alloy foams has been determined in structures whose void fraction varies from 0.80 to 0.95 of the total volume.
Abstract: The compressive flow behavior of Al, Al−7 pct Mg and 7075 Al alloy foams has been determined in structures whose void fraction varies from 0.80 to 0.95 of the total volume. In all cases, a greater than linear increase in flow strength with increase in density was exhibited, indicating that bending stresses within the foam structure are an important feature of the collapse mode. The flow strength did not follow proportionately changes in bulk flow strength in comparisons of either alloy or of heat-treatment conditions. Ancillary tensile and metallographic observations show that this lack of correlation arises because the different foams collapse by different modes with localized fracture becoming dominant in the higher strength 7075 alloy. The energy absorbing efficiency was found to be independent of foam density for all the materials. However, the efficiency was found to be a strong function of the alloy and heat treatment increasing from about 30 pct in Al, to 43 pct in Al−7 pct Mg and to 50 pct in the solution heat treated and aged 7075 alloy. The increase in efficiency occurs because of an increase in the propensity to fracture in the higher strength alloys which introduces the potential for a propagating constant-stress collapse process.
TL;DR: In this paper, the authors describe the behavior of a carbon-fibre reinforced epoxy composite when deformed in compression under high hydrostatic confining pressures and show that the failure strength of the composite increased rapidly with increasing confining pressure, though the elastic modulus remained constant.
Abstract: This paper describes the behaviour of a carbon-fibre reinforced epoxy composite when deformed in compression under high hydrostatic confining pressures. The composite consisted of 36% by volume of continuous fibres of Modmur Type II embedded in Epikote 828 epoxy resin. When deformed under pressures of less than 100 MPa the composite failed by longitudinal splitting, but splitting was suppressed at higher pressures (up to 500 MPa) and failure was by kinking. The failure strength of the composite increased rapidly with increasing confining pressure, though the elastic modulus remained constant. This suggests that the pressure effects were introduced by fracture processes. Microscopical examination of the kinked structures showed that the carbon fibres in the kink bands were broken into many fairly uniform short lengths. A model for kinking in the composite is suggested which involves the buckling and fracture of the carbon fibres.
TL;DR: In this article, a chain unfolding process smoothes the surface inhomogeneities of the fibrils caused by micro-fibril ends which act as point defects of the microfibrillar lattice.
Abstract: The plastic deformation of fibrous material occurs primarily by a sliding motion of fibrils. To a first approximation, the displacement of their centers of mass can be well described by an affine transformation corresponding to the deformation of the bulk sample. Such a sliding motion of fibrils does not affect the morphology of the microfibrils. But by chain unfolding, it smoothes the surface inhomogeneities of the fibrils caused by microfibril ends which act as point defects of the microfibrillar lattice. This makes possible a more perfect lateral contact between adjacent fibrils and results in a steadily increasing resistance to plastic deformation. The sliding motion of fibrils produces a shear stress on skewed fibrils and this causes a slight shear displacement of microfibrils. But in spite of its smallness, this shear displacement enormously extends the interfibrillar tie molecules by chain unfolding and thus increases their fraction in the amorphous layers.
TL;DR: A sigmoidal relationship was observed between strain rate and stress in the Zn-22% Al eutectoid alloy, dividing the behavior into three distinct regions as mentioned in this paper, and the results support the suggestion that the behavior in this region arises from an intragranular creep process.
TL;DR: In this paper, deformed and partially recrystallised oligoclase porphyroclasts were studied in a high voltage electron microscope, and it was suggested that the recovery process was aided by strain enhanced diffusion, and the resultant new grains had a lower anorthite content than their parents.
Abstract: Naturally deformed and partially recrystallised oligoclase porphyroclasts were studied in a high voltage electron microscope. The oligoclases had a highly deformed outer mantle zone, which contained high densities of dislocations and albite and pericline deformation twins, and less deformed cores containing fewer dislocations and albite twins but no pericline deformation twins. There was little evidence for recovery; apparently the internal strain energy due to deformation was relieved by recrystallisation. Strain free nuclei developed in areas with the highest defect densities. The resultant new grains had a lower anorthite content than their parents. It is suggested that the recrystallisation processes were aided by strain enhanced diffusion.
TL;DR: In this article, the influence of hydrostatic pressure (∼ 6.5 kbar) on the stress for plastic flow in Pd77.5Cu6Si16.5 amorphous metallic alloy in compression and tension was examined.
Abstract: The influence of hydrostatic pressure (∼ 6.5 kbar) on the stress for plastic flow in a Pd77.5Cu6Si16.5 amorphous metallic alloy in compression and tension has been examined. The observed effect (δlnσ/δP ∼- 5×10−6 bar−1) is very close to that exhibited by crystalline metals. The highly inhomogeneous nature of the deformation appears to be unaltered by pressure. As at one atmosphere, failure in tension with high superposed pressure occurs by rupture through a zone of intense plastic shear. The fracture surface topography is strikingly different, however, because cracking inside the shear zone is suppressed in favour of crack initiation at its periphery.
TL;DR: In this article, an equation for the mechanical behavior of polyurethane foams as a function of foam density is provided, starting from a model conception and the qualitative microscopic consideration of the deformation and failure mechanism, simple relations are found for the tensile, compressive and shear strength and the elastic modulus.
Abstract: Rigid plastic foams find application in construction mainly as core materials for loaded sandwich structures—in buildings, ground vehicles, and airplanes. This work provides an equation for the mechanical behavior of polyurethane foams as a function of foam density. Starting from a model conception and the qualitative microscopic consideration of the deformation and failure mechanism, simple relations are found for the tensile, compressive and shear strength and the elastic modulus, which sufficiently express the measured results.
TL;DR: In this article, the authors focus on the loading rate of the region bounded by a ring of maximum thinning referred to here as the crown, which is associated with the onset of a rapid rate of thinning under falling crown load.
Abstract: Criteria for diffuse and local necking in sheet metals stretched over a hemispherical punch have been developed. During stretching, a peak develops in the distribution of strain across the dome. This peak is a ring of thinned material around the pole which moves outward radially with continued deformation. The present approach essentially focuses on the loading rate of the region bounded by this ring of maximum thinning referred to here as thecrown. While diffuse instability is identified with a vanishing rate of crown loading, local necking is associated with the onset of a rapid rate of thinning under falling crown load. The principal surface strains were measured from incremental stretching of several different materials and time dependent constitutive relations were used to predict the instability strains. Such predictions agree with experimentally observed forming limits defined by the onset of visible necking and provide an understanding of the failure of biaxially stretched sheets deformed by a rigid punch. Since no satisfactory plasticity analyses have been developed to predict the strain distribution during punch stretching, the empirical input to the present instability criterion is required.
TL;DR: In this paper, the effect of rate of deformation on mechanical properties such as ultimate shear strength, shear energy, ultimate compressive strength perpendicular to plant axis and modulus of toughness was also studied.
TL;DR: In this article, the yield and work hardening of ferrite - pearlite aggregates with continuous ferrite matrix have been studied, special attention being paid to the relative deformation of the individual constituents, which was followed by TEM and measurements of microhardness and X-ray line broadening.
TL;DR: Extensive plastic deformation of diamond crystals can be accomplished by squeezing diamond embedded in diamond powder at high pressures and temperatures as mentioned in this paper.By inhibiting brittle fracture, deformation takes place at temperatures as low as 900°C at 60kb.
TL;DR: In this paper, the growth of necks in relatively smooth tension creep samples with non-uniform cross-sections is studied using numerical techniques, and the shape of the sample and the average creep rate are calculated as a function of average strain or time for various initial shapes and creep stress exponents for both the constant load and constant stress conditions.
TL;DR: In this paper, the mechanism of deformation under the indentation of MgO crystals has been studied by transmission and scanning electron microscopy, and the dislocation structure and Burgers vectors of rosette dislocations are determined.
Abstract: The mechanism of deformation under the indentation of MgO crystals has been studied by transmission and scanning electron microscopy. The dislocation structure and Burgers vectors of rosette dislocations are determined. The nature and geometry of cathodoluminescence around indentation have been also investigated. The luminescence radiation is shown to be caused by interstitial point defects built up under indentation.
[Russian text ignoreed].
TL;DR: In this article, it is argued that transgranular mass transfer and grain-boundary sliding are interdependent deformation processes and can in no sense make separate contributions to the total diffusion creep strain.
TL;DR: In this article, the behavior of narrow molecular weight distribution polymers has been investigated under uniaxial extension at constant deformation rate and at constant stress, and it has been established that up to rupture these polymers behave as linear viscoelastic bodies.
Abstract: The behavior of narrow molecular weight distribution polymers has been investigated under uniaxial extension at constant deformation rate and at constant stress. It has been established that up to rupture these polymers behave as linear viscoelastic bodies. A detailed investigation of the rupture phenomenon has shown that the rupture of fluid polymers is due to their transition to the rubbery state at critical deformation rates, with the result that they disintegrate like quasi-cured rubbers. The effect of the temperature and the molecular weight on the critical conditions of rupture has been described in terms of viscoelastic relaxation.
Book•
01 Jan 1975
TL;DR: In this article, the authors studied the topology of metamorphic phase diagrams and calculated the slopes of reaction curves, as well as the location of the reaction curves. But they did not study the relationship between the number of phases and the stability of one phase on the other.
Abstract: 1 Background Discussion.- Scope of Metamorphism.- Temperatures and Pressures of Metamorphism.- Movement of Material in Metamorphism.- Mineral Assemblages ('Pangeneses').- Microstructures of Metamorphic Rocks.- Preferred Orientation in Metamorphic Rocks.- Metamorphic Grade.- Metamorphic Facies.- Tectonic Setting of Metamorphism.- References.- 2 Equilibrium Aspects of Metamorphic Reactions.- Driving Force for Metamorphic Reactions.- Types of Metamorphic Reactions.- Variance of Metamorphic Reactions.- Metamorphic Reactions and Resulting Assemblages.- Sliding Reactions at Isograds.- Effect of One Phase on the Stability of Another.- Criteria of Stable Coexistence of Metamorphic Minerals.- Domains of Local (Mosaic) Equilibrium.- Calculation of the Topology of Metamorphic Phase Diagrams (Schreinemakers' Analysis).- Calculation of Slopes of Reaction Curves.- Experimental Location of Reaction Curves.- Reversal of Experimental Reactions.- Discrepancies Between Calculated and Experimentally Determined Reaction Curves.- Open Systems in Metamorphism.- Fluid Phase in Metamorphism.- Pressure of Fluid Phase.- Effect of Fluid Pressure on Reaction Curves.- Effects of Composition of Fluid Phase (Fugacities of Mixed Volatile Components) on Reaction Curves.- Effect of Oxygen Fugacity.- Coexisting Magnetite and Ilmenite.- Effect of fO2 on Hydrous Silicates Without Cations of Variable Valency.- Distribution of Elements Between Coexisting Minerals.- References.- 3 Kinetics of Metamorphic Reactions.- Diffusion in Metamorphism.- Nucleation and Growth.- Application of Reaction Kinetics to Metamorphism.- Zoning in Metamorphic Minerals.- Problems of Aragonite in Metamorphic Rocks.- Kinetics of the Reaction: Calcite + Quartz ? Wollastonite + CO2.- References.- 4 Reactions in Metamorphic Rocks.- Mechanisms of Metamorphic Reactions.- Reactions in Metapelitic Systems.- Reactions in Mafic and Ultramafic Systems.- How Relevant Are Available Experimental and Theoretical Determinations of P-T-X Equilibria?.- Retrograde Reactions.- Reactions Involving Zoned Minerals.- Reactions Involving Zoned Garnet.- Compositional Changes During Metamorphism ('Metamorphic Differentiation').- References.- 5 Stable Metamorphic Microstructures.- Unstable Grain Arrangements.- Stable Grain Arrangements in Isotropic Single Phase Aggregates.- Anisotropic Single Phase Aggregates.- Aggregates with More than One Phase.- Spatial and Size Distribution of Grains in Metamorphic Rocks.- Environments of Grain Adjustment in the Solid State.- References.- 6 Deformation, Recovery and Recrystallisation Processes.- Brittle Versus Ductile Deformation.- Crystal Plasticity.- Primary Modes of Intragranular Plastic Deformation.- Secondary Modes of Deformation.- Dislocations.- How Do Dislocations Assist Deformation?.- Experimental Detection of Dislocations.- Mobility of Dislocations.- Production of Dislocations.- Dislocations in Relation to Work-Hardening and -Softening.- Partial Dislocations.- Dislocations in Non-Metals.- Surface Imperfections 160 Effect of Grain Boundaries on Deformation (Intergranular Deformation).- Recovery and Recrystallisation 166 Development of Crystallographic Preferred Orientation by Recrystallisation.- Development of Preferred Orientations by Deformation.- Some Generalities.- Appendix: Methods of Detecting Slip Systems.- References.- 7 Deformation, Recovery and Recrystallisation of Some Common Silicates.- Quartz.- Microstructural Features of Deformed Quartz.- Experimental Deformation, Recovery and Recrystallisation of Quartz.- Natural Deformation, Recovery and Recrystallisation of Quartz.- Preferred Orientation.- Variation in Quartz Microfabric with Metamorphic Conditions.- Stress Indicators in Deformed Quartz.- Olivine.- Experimental Deformation, Recovery and Recrystallisation of Olivine.- Natural Deformation, Recovery and Recrystallisation of Olivine.- Preferred Orientation of Olivine.- Layer Silicates.- Deformation of Mica Single Crystals.- Deformation of Fine-Grained Layer Silicate Aggregates.- Recovery and Recrystallisation of Mica Single Crystals.- Experimental 'Recrystallisation' of Fine-Grained Layer Silicate Aggregates.- Preferred Orientation Mechanisms in Layer Silicates.- Systematic Study of Natural Deformation and Recrystallisation of Mica.- Plagioclase.- Experimental Deformation of Plagioclase.- Natural Deformation of Plagioclase.- Experimental Recrystallisation of Plagioclase.- Natural Recrystallisation of Plagioclase.- Generalisations.- References.- 8 Relationships between Chemical and Physical Processes in Metamorphism.- Effect of Chemical Reactions on Rock Mechanical Properties.- Effect of Differential Deformation on Mineral Assemblage.- Examples of Metamorphic Layering Formed By Preferential Removal of Minerals.- Large-Scale Metasomatism and Deformation.- Pegmatites and Deformation.- Migmatites.- Time Relationships between Deformation and Mineral Growth.- Solution Transfer.- Spinodal Decomposition?.- References.- Author Index.
TL;DR: In this paper, it was shown that slip can play a major role in plastic deformation, and that the observed mechanical properties result from the peculiar characteristics of the dislocations.
Abstract: The alloy titanium-6 Al-4 V has been processed in the laboratory to develop a wide range of textures, and determinations have been made of the yield loci for these conditions. Optical and electron metallography have been used to gain information about the operative deformation modes under various states of stress. Only limited texture strengthening is observed for conditions of tensile loading, although quite significant effects are found in compression. In strongly textured material a large strength differential occurs along thec axis direction, but this cannot be attributed to twinning. It is shown that slip can play a major role in plastic deformation, and that the observed mechanical properties result from the peculiar characteristics of the dislocations.