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International audience; Automatic orientation mapping is an important: addition to standard capabilities of conventional transmission electron microscopy (TEM) as it facilitates investigation of crystalline materials. A number of different such mapping systems have been implemented. One of their crucial characteristics is the orientation resolution. The precision in determination of orientations and misorientations reached in practice by TEM-based automatic mapping systems is the main subject of the paper. The analysis is Focused on two methods: first, using spot diffraction patterns and `template matching', and second, using Kikuchi patterns and detection of reflections. In simple terms, for typical mapping conditions, their precisions in orientation determination with the confidence of 95% are, respectively, 1.1 degrees and 0.3 degrees. The results are illustrated by example maps of cellular structure in deformed Al, the case for which high orientation sensitivity matters. For more direct comparison, a novel approach to mapping is used: the same patterns are solved by each of the two methods. Proceeding from a classification of the mapping systems, the obtained results may serve as indicators of precisions of other TEM-based orientation mapping methods. The findings are of significance for selection of methods adequate to investigated materials.

The paper presents joint zone microstructure and the test results obtained for fatigue cracks in zirconium-steel bimetal under bending. The materials were joined with explosive welding technology, and special attention was paid to characteristics of the joint zone.

Capabilities of crystal plasticity finite element (CPFE) model in application to modeling polycrystalline aluminum sample behavior during plain strain compression test are discussed within the present work. To simplify analysis of material behavior during plain strain compression the aluminum specimen is composed of only three grains, both in experiment and numerical simulation. To reconstruct appropriate grains morphology a digital material representation (DMR) technique is used. The predicted/calculated values of loads and pole figures are compared with the experimental data. Calculated results remain in good agreement with experimental data what highlight predictive capabilities of the proposed approach in modeling material behavior under loading conditions. The conclusions regarding model capabilities and possible improvements during further work are also drawn in the paper.

The main purpose of the present work is to describe the qualitative and quantitative behaviours of aluminium during high strain plastic deformation and the effect of deformation on the subsequent recrystallization process. An Electron Backscatter Diffraction analysis of aluminium after the Equal channel angular pressing (ECAP) and recrystallization process is presented. In order to do this, several topological maps are measured for samples processed by 4 and 8 passes and recrystallized. The processing was conducted with route C. For all samples, distributions of grain size, misorientation, image quality factor (IQ) and texture were preceded and then analysed in some detail.

The microstructure changes and the phase constitution within the layers close to the bonding interface strongly influence the properties of bimetallic strips. In this work, the layers near the interface of explosively welded aluminum and copper plates were investigated by means of microscopic observations, mostly with the use of transmission electron microscopy (TEM) equipped with energy dispersive spectrometry (EDX). The study was focused on the identification of the intermetallic phases, the possible interdiffusion between the copper and the aluminum, and the changes in the dislocation structure of the parent plates. In macro-/mesoscale, the interfaces were outlined by a characteristic sharp transition indicating that there was no mechanical mixing between the welded metals in the solid state. In micro-/nanoscale, the layers adhering to the interface show typical deformed microstructure features, i.e., structure refinement, elongated dislocation cells, slip bands, and microtwins (in copper plate). The internal microstructure of the intermetallic inclusion is composed mostly of dendrites. The electron diffractions and TEM/EDX chemical composition measurements revealed three crystalline equilibrium phases of the γ-Al4Cu9, η-AlCu, and Θ-Al2Cu type (the last one was dominant). However, most of the observed phases of the general Cu m Al n type (also crystalline) do not appear in the equilibrium Al-Cu phase diagram. Inside the intermetallic inclusions, no significant regularity in the phase distribution with respect to the parent sheets was observed. Therefore, it was concluded that the processes occurring in the melt determined their local chemical composition.

The objective of this study was to determine the effect of ECAP-processing on the texture and the microstructure development of the deformed and recrystallized material. The commercial purity AA4343 aluminium alloy, containing very large second phase particles (SPP) of pure silicon, was deformed via route C up to 10 passes and then annealed. The samples were characterized by TEM and SEM equipped with high resolution EBSD. It was found that the microstructure of the deformed state in areas far from coarse SPP was very similar to that observed in pure aluminium. The orientations of the new grains were scattered but not random and only specific groups of orientations were observed.

The crystal lattice rotations induced by shear bands formation have been examined in order to investigate the influence of grain boundaries on slip propagation and the resulting texture evolution. The issue was analysed on Al-0.23wt.%Zr alloy as a representative of face centered cubic metals with medium-to-high stacking fault energy. After solidification, the microstructure of the alloy was composed of flat, twin-oriented, large grains. The samples were cut-off from the as-cast ingot in such a way that the twinning planes were situated almost parallel to the compression plane. The samples were then deformed at 77K in channel-die up to strains of 0.69. To correlate the substructure with the slip patterns, the deformed specimens were examined by SEM equipped with a field emission gun and electron backscattered diffraction facilities. Microtexture measurements showed that strictly defined crystal lattice re-orientations occurred in the sample volumes situated within the area of the broad macroscopic shear bands (MSB), although the grains initially had quite different crystallographic orientations. Independently of the grain orientation, their crystal lattice rotated in such a way that one of the f111g slip planes became nearly parallel to the plane of maximum shear. This facilitates the slip propagation across the grain boundaries along the shear direction without any visible variation in the slip plane. A natural consequence of this rotation is the formation of specific MSB microtextures which facilitates slip propagation across grain boundaries.

Early stages of recrystallization were observed for the technical purity aluminium alloy (AA1050). The samples were severely deformed by equal channel angular pressing and then annealed to obtain the state of partial recrystallization. The nucleation of new grains and the changes in ‘density’ of low- and high- angle boundaries were analysed using scanning electron microscopy equipped with high resolution EBSD system. After deformation in six passes along route A the alloy contained a structure of flat grains. On annealing, the structure coarsened and got transformed into nearly equiaxed grains by both discontinuous and continuous recrystallization. A particular role in the rise of nuclei and the structure spheroidization is attributed to migration of low-angle boundaries.

The crystallographic aspects of recrystallization nucleation have been characterized in Al-1%wt.Mn single crystals of Goss{110} and brass{110} orientations. Samples were compressed 40% and then lightly annealed to partial recrystallization. SEM/EBSD orientation maps revealed that boundaries with misorientation angles above 8° are not present in the deformed structures. During annealing high angle boundary segments (>15°) were created at an advanced stage of recovery preceding grain nucleation, i.e. some of the low-angle boundaries evolve into high-angle boundaries. As the dislocation-free subgrains are now partly or completely surrounded by high-angle boundaries, the orientations of nuclei are different from the orientations of their deformed/recovered neighbours. There is also a strong relation between as-deformed orientations and the limited number of recrystallized grain orientations. The results are discussed in terms the creation of twist or tilt grain boundaries of high misorientation by thermally activated, co-ordinated movement of dislocations during recovery.

The structure near the interface of bimetallic strips strongly influences their properties. In this work, the interfacial layers of explosively welded aluminium and copper plates were investigated by means of a scanning electron microscope (SEM), equipped with a high resolution system for local orientation measurements (SEMFEG/EBSD), and a transmission electron microscope (TEM), equipped with energy dispersive spectrometry (EDX) for the analysis of chemical composition changes. The SEMFEG/EBSD-based local orientation measurements in the areas close to the interface, in both sheets, revealed fine-grained layers characterized by the clearly marked tendency of the copper-type rolling texture formation. The texture was described by an increased density of the orientations near the {112}, {123}and {110}positions. The internal microstructure of the intermetallic inclusion is mostly composed of dendrites. The electron diffractions and the TEM/EDX chemical composition measurements in the intermetallic inclusions revealed only crystalline phases, both equilibrium and ’metastable’. Additionally, no significant regularity in the phase distribution with respect to the parent sheets was observed.

Early stages of recrystallization in alloys containing complex structure of second phase particles are of considerable practical interest. They were observed for the AA3104 alloy in which large particles occur against the background of randomly distributed dispersoids. The samples were deformed by equal channel angular pressing and then slightly annealed to obtain the state of partial recrystallization. The highly deformed alloy contained a structure of flat grains with the spacing between high-angle grain boundaries ranging from 100 nm to 1 µm. On annealing, the structure coarsened and got transformed into nearly equiaxed grains by both discontinuous and continuous recrystallization. The nucleation of new grains was observed in statically recrystallized bulk samples using scanning electron microscopy, and during in-situ recrystallization in a transmission electron microscope. Special attention was paid to the nucleation of new grains in areas close to large second phase particles, where a relatively high stored energy was expected to stimulate nucleation. A particular role in the rise of nuclei is attributed to migration of low angle boundaries. During recrystallization at 623 K (350 °C), in most of the observed cases, the growth of grains occurred by coalescence of neighbouring cells and by migration of high-angle grain boundaries. These processes led to nearly equiaxed grains of similar size. Orientation mappings showed that although orientations of new grains were widely scattered, they were not completely random.

The objective of this study was to determine the effect of deformation mode on recrystallization behavior of severely deformed material. Commercial purity AA3104 aluminum alloy was deformed via high pressure torsion and equal channel angular pressing to different strains and then annealed to obtain the state of partial recrystallization. The microstructure and the crystallographic texture were analysed using scanning and transmission electron microscopes equipped with orientation measurement facilities. The nucleation of new grains was observed in bulk recrystallized samples and during in-situ recrystallization in the transmission microscope. Irrespective of the applied deformation mode, a large non-deformable second phase particles strongly influenced strengthening of the matrix through deformation zones around them. It is known that relatively high stored energy stimulates the nucleation of new grains during the recrystalization. In most of the observed cases, the growth of recrystallized grains occurred by the coalescence of neighboring subcells. This process usually led to nearly homogeneous equiaxed grains of similar size. The diameter of grains in the vicinity of large second phase particles was only occasionally significantly larger than the average grain size. Large grains were most often observed in places far from the particles. TEM orientation mapping from highly deformed zones around particles showed that orientations of new grains were not random and only strictly defined groups of orientations were observed.

The objective of this study was to determine the effect of ECAP-processing on the texture and the microstructure development of the deformed and recrystallized states. The commercial purity AA3104 aluminum alloy was deformed via route A up to 7 passes and then annealed to obtain the state of partial recrystallization. The shear bands formation and the texture transformation in annealing were investigated with the use of high resolution transmission and scanning electron microscopes equipped with the facilitates for the local orientation measurements. It was found that the instability of the layered structure of the flat grains within some narrow areas led to the formation of the kink-type bands, which were precursors of the shear bands. The orientations of the new grains occurring in the recrystallized samples were not random, i.e. only specific groups of orientations were observed. In most of the observed cases, the growth of the recrystallized grains led to nearly homogeneous equiaxed grains of a similar size.

The results of studies carried out on AA1200 aluminum alloy deformed by Accumulative Roll Bonding (ARB) are presented in this paper. The commercial purity material was deformed up to 10 cycles (equivalent plastic strain of 8) at room temperature. The deformed microstructures and the crystallographic textures were characterized by transmission (TEM) and scanning (SEM) electron microscopes and high resolution orientation mapping. It was found that increased deformation leads to a strong increase of quantity of high angle (>15°) grain boundaries and strong grain refinement (up to 200-300 nm). The microstructure observations and TEM and SEM local orientation measurements allowed identifying fine and strongly disoriented planar dislocation structure of nanolayers described by strong texture components close to two nearly complementary positions of {112} orientation.

The paper describes the mechanism of deformation at 77 K of pure aluminum bicrystals of different grain orientations. The following orientations were selected: {100}/{110} (cube/Goss) and - {100}/{100} (cube/shear) to represent the unstable vs. stable and the unstable vs. unstable behaviours, respectively. The bicrystalline samples were deformed in the plane strain conditions with the use of a channel-die immersed inside a reservoir with liquid nitrogen. The low temperature deformation increases the tendency to form plain strain inhomogeneities of the deformation in the grains with an unstable orientation. In both sets of crystallite compositions, the grain boundary was situated perpendicularly to the compression plane. A particular interest was paid to the analysis of the tendencies of the crystal lattice rotations near the grain boundary and the description of the deformation behaviour of the material in the macro- scale (hardening behaviour). A detailed analysis of the crystal lattice rotations was possible with the application of the local orientation measurements by means of scanning and transmission electron microscopes, equipped with the electron backscattered diffraction and convergent beam electron diffraction facility, respectively. The experimental results of the local orientation measurements were used to evaluate the accuracy of the numerical prediction of the macro-scale behaviour of bi-crystalline samples by a single Cristal Plasticity Model. The investigation shows that the crystallites behave essentially as single crystals in the same deformation conditions. Due to the similar hardening behaviour of the investigated crystallites (similar values of the Taylor factors) the grain boundary remains unchanged. The calculated lattice rotations are similar to those observed experimentally. Key words: aluminium bi-crystals, texture, microstructure, single crystal plasticity model

The development of the multi billet extrusion technology for manufacturing bi-layered aluminum based semi-products for heat radiators is the subject of this work. To obtain increased strength of the product, ultra fine grained ECAP billets were prepared and used during the extrusion. Appropriate deformation route to get desirable level of grain refinement and billet quality were identified by a series of experiments and numerical simulations performed with the implemented microstructure evolution model. Similar combination of experimental and numerical research was used within the paper for identification of dies geometry and process parameters during development of the multi billet extrusion technology.

In this study, the commercial purity Al/Cu plates were bonded through the explosive welding process. The SEM/EBSD local orientation measurements were conducted to consider the changes in the microstructure and the development of texture gradients for the applied explosive loading. A particular attention was paid to the texture changes across the interface. The detailed local orientation measurements show that the ultra-fine grained layers are formed close to the bonding zone. The layers were characterized by the copper-type rolling texture components. The interface was outlined by a characteristic sharp transition between the two materials. However, in some places, local melted zones were also encountered, mainly in the front slope of the waves.

Aspects of crystal subdivision and nucleation of recrystallization in fcc-lattice metals are studied by TEM-based orientation mapping. This method is suitable to study fine-grained materials because of the good spatial resolution and a direct comparison of the orientation distribution with the dislocation structure is possible. Orientation measurements of subcells in the deformed state shows that and the unstable behavior leads strain inhomogeneities and therefore to specific texture components. The first-formed nuclei develop within the as-deformed dislocation structures; successive stages of recrystallization are observed in annealed samples.

International audience; A systematic study of crystal lattice reorientation in early stages of recrystallization has been carried out to correlate the orientations of recrystallization nuclei with the deformation microtexture and with slip systems. Microstructure and texture of Al-1 wt.% Mn single crystals of unstable initial orientations of {112} < 111 >, {100} < 001 > and {001} < 110 > have been examined by high-resolution field-emission gun scanning electron microscope local orientation measurements. All single crystals were channel-die deformed at room temperature and then annealed for a short time. It was shown that often observed presence of the < 112 > directions as rotation axes in the formation of new nuclei orientation directly suggested a close link with the deformation process.

Summary The microstructure and texture of Cu–8 at.% Al alloy single crystal with (112)[11] orientation plane strain compressed at 77 K were characterized by scanning electron microscope and transmission electron microscope orientation mappings in order to investigate the influence of twins and shear bands on slip propagation across a structure of twin-matrix layers and the resulting texture evolution. It was shown that the strong, initial texture changes are due to deformation twinning at low deformations. At larger deformations, twin-matrix bending within some narrow areas led to the formation of kink-type bands, which became the precursors of shear bands. It is shown with scanning electron microscope and transmission electron microscope orientation mappings how the structure of twins and matrix was incorporated into the shear band, and what kind of the dislocation mechanism was responsible for strain accommodation at the macroscale. It was found that the reorientation of the main (111) twinning planes towards the shear band plane facilitates further dislocation slip in the shear direction.

Periodic crystal lattice rotations within compact clusters of shear bands, developed in copper, have been characterized over a range of scales by optical microscopy, high resolution FEG-SEM-EBSD and TEM orientation mapping, to examine the role of local lattice re-orientation on slip propagation across pre-existing barriers to dislocation motion. Two different cases were analysed in detail. The single crystal analysis addresses the relation between the crystallographic microtexture and microstructure development due to the crystal anisotropy after a strain path change. All the changes in strain path directly lead to crystallite subdivisions and strain localization in the form of macroscopically visible bands of different morphology at the micro scale. The elongated cell substructure formed during primary straining was the source of anisotropy after changing deformation path. It is thought that the presence of this structure (here subcells) as barriers to dislocation motion is crucial for the occurrence of shear banding. The analysis of pure polycrystalline copper has been focused on the influence of local lattice re-orientations within particular grains on slip propagation across grain boundaries. The crystal lattice rotated in such a way that one of the {111} slip planes became nearly parallel to the direction of maximum shear (due to the actual state of anisotropy). A natural consequence of this rotation was the formation of a specific microtexture which facilitated slip propagation across grain boundaries.

The objective of the study was to determine the effect of strain path on texture, microstructure and mechanical properties development of severely deformed Al-Mn-Mg alloy. The commercial purity material (AA3104 alloy) was deformed via Equal Channel Angular Pressing (ECAP) up to 10 passes following routes A, B, and C. The deformed and partially recrystallized microstructures and the crystallographic textures were characterized by transmission (TEM) and scanning (SEM) electron microscopy including systematic local orientation measurements (TEM and SEM FEG orientation mapping). The crystallographic texture was determined using X-ray diffraction on a sample section perpendicular to the extension direction (ED). In order to estimate the homogeneity of strengthening the systematic measurements of Vickers micro hardness in the plane perpendicular to the ED was performed. It was found out that different routes led to strong differences in microstructure of billets. In the case of route A and B strong macro cracking appeared after 5 and 3 passes, respectively. A good quality billet after 10 passes was obtained only in the case of route C. Texture evolution turned out to follow nearly the same ‘course’ for different routes of ECAP. However, the intensity of particular texture components was different in each case. TEM observations and local orientation measurements allowed identifying fine and strongly disoriented planar dislocation structure of nanolayers in the case of route A and C. In the case of route B nearly equiaxed structure of fine grains was observed after 3 passes. Moreover, irrespective of the applied deformation routes large, not deformable second phase particles strongly influenced strengthening of the matrix and nucleation during the recrystallization.

The development of the new technology for manufacturing of multi layer aluminium based materials for heat radiators is the subject of this work. Modern aluminium alloys can be specially processed in a controlled manner to obtain nano(mikro) structures. These ultra fine grained structures play a significant role because they provide a possibility to obtain final product that is characterized by elevated strength properties and, at the same time, good anticorrosion and soldering properties. A detailed understanding of these ultra fined structures using a combination of numerical modelling and experimental analysis is presented in this paper. Particular attention is put on implementation of the microstructure evolution model into the finite element software to simulate Equal Channel Angular Pressing (ECAP) process. Examples of the obtained results are presented and discussed.

The intensity of recrystallization twinning has been characterized in {110} and {110} oriented single crystals of Al-l%wt.Mn deformed to a strain of 0.5 and then lightly annealed. SEM/EBSD measurements indicate that the quantity of recrystallization twins depends on the sample depth. In partly recrystallized sample of {110} orientation the highest fraction of twinned grains was observed in the Vi sample section, but on the surface in the case of {110} crystals. Most of the grains that fulfil the Brandon criterion for twin-related areas are in fact incoherent twins since the boundary plane does not coincide with a {111} plane. A new algorithm to identify coherent and incoherent twin boundaries was applied. In the case of coherent twins, most of the twinning plane normals lie among the rotation axes of the misorientation relations between the recrystallized grains and their as-deformed neighbourhood. The incoherent twins always appear between the growing grains.

The influence of grain misorientation on pure aluminium hardening is presented. The study has been focused on plastic strain inhomogeneities developed in high purity aluminium bicrystals deformed in channel die at 77K, with various combinations of grain orientations and with the grain boundary situated parallel to the compression plane. The character of the structure was determined by optical microscopy as well as by systematic local orientation measurements using high resolution EBSD in SEM-FEG scanning electron microscope. The experiment results were compared with crystal plasticity finite element simulations used for prediction of local deformation areas. The behavior of each bicrystal was described by two flow curves obtained from plane strain compression tests of single crystals with different orientations. As a result, clear effect of the grain orientations and grain boundary misorientation on the deformation kinematics within both crystallites forming bicrystals has been observed.

The nucleation of new grains during annealing in high purity single crystals of Cu-8%wt. Al alloy with initial (112)[111] orientation has been characterized by detailed transmission electron microscopy (TEM) orientation measurements. The samples were channel-die deformed and then recrystallized to form a substructure composed of a mixture of deformation twins, shear bands (SBs) and the recrystallized grains. Substantial progress in understanding the mechanism of texture transformations at the early stages of recrystallization was possible thanks to orientation mapping using TEM. Microtexture analysis of partly recrystallized samples indicates a simple 25-40o ( or ) relation, most frequently observed during the early stages of recrystallization between single nuclei and one of the two as-deformed groups of components (twins or matrix). As recrystallization proceeds, recrystallization twinning develops strongly and facilitates rapid growth of the recrystallized phase. The first and higher generations of twins systematically tend to obscure the initial crystallographic relation between the deformed state and the recrystallization nuclei.

Microstructure and texture development in twinned fcc metals is investigated in order to characterize the influence of micro- and macro-scale brass-type shear bands (SB) on structural and textural changes at large deformations. TEM and SEM analyses are focused on bands developed by plane strain compression in twinned C{112} oriented single crystals. The proposed crystallographic model of the shear banding phenomenon refers to the idea of local lattice reorientation within narrow areas. Most of these rotations occur around the TD|| axis with significant further rotations about poles. These two rotations explain the influence of SB’s on the formation of Goss{110} and brass{110}-S{123} texture components clearly observed in highly deformed low SFE metals. At high deformations symmetrically equivalent crystal lattice rotations inside narrow areas lead to the formation of positive and negative macroscopic SBs.

W pracy opisano rozwój pęknięć zmęczeniowych w układach platerów cyrkon-stal spajanych metodą zgrzewania wybuchowego. Próbki o przekroju poprzecznym prostokątnym, charakteryzujące się zróżnicowanym udziałem warstwy przetopionej, poddano wahadłowemu zginaniu oraz wykonano pomiary twardości w obszarze złącza. W odkształconych próbkach zaobserwowano wzrost pęknięć zmęczeniowych równolegle do przyłożonego obciążenia. Inicjacja pęknięć występowała w cyrkonie. Fatigue life Zr-CS bimetal in terms of the characteristics of the joint Abstract The paper describes a fatigue crack development in zirconium-steel sheets joined by the explosive welding technology. The clad specimens of rectangular cross-section and with different quantity of melted areas were subjected to oscillatory bending. The strain hardening across the interface was analysed by microhardness measurements. In the specimens, the fatigue crack growth parallel to the applied loading was observed. The crack initiation occurred always in the zirconium plate.

The crystallography of recrystallization nucleation has been investigated in channel-die deformed pure aluminium bicrystals with {100}/{110} and {100}/{110} orientations. The new grain orientations and misorientations were followed by systematic local orientation measurements using SEM and semi-automatic measurements in a TEM. In particular, orientation mapping combined with in-situ sample heating was used to investigate the formation and growth of new grains and their crystallographic orientation changes at very early stages of recrystallization. Grain boundary migration and ‘consumption’ of the as-deformed areas was always favoured along directions parallel to the traces of the {111} slip planes that had been most active during deformation. The orientations of the first formed nuclei were misoriented with respect to the orientations identified within the neighbouring deformed areas by α(, , or )relations.

The local crystallography within shear bands (SB) has been examined in a single crystal of {112} orientation of pure copper deformed at 77K by channel-die compression to strains of about 1. Setting up a system for making high-resolution orientation maps using transmission electron microscopy (TEM) has opened new advantageous circumstances for the analysis of orientation changes within SB. This method with spatial resolution higher than 10nm allows the examination of microstructure images composed of nanoscale subcells forming SB. It has been found that for well-developed shear bands, a crystal lattice rotation about direction tends to dominate and this process is usually accompanied by activation of new slip systems. The present work shows that despite the plane strain deformation mode, the mechanism of lattice rotation within emerging SBs may lead to Goss and Brass texture components.

The issues of brass-type shear band formation and the evolution of band microtexture components are addressed. The analysis is based on bands developed by plane strain compression in twinned {112}〈111〉 oriented copper single crystals deformed at 77 K. Substantial progress in understanding the formation of the bands was possible thanks to systematic local orientation measurements using transmission electron microscopy (TEM). The TEM orientation maps allowed investigation of the way in which unstable behavior of twin-matrix layers leads to the brass-type shear bands. It has been found that several important transitions of the deformation textures are correlated with shear banding. Early stages of shear band formation are the result of the equally effective operation of two coplanar slip systems on the {111} slip planes. This process leads to the lattice rotation about the 〈110〉 axis and to the rise of Goss orientation. For well-developed shear bands, a second rotation about the 〈112〉 direction is observed. It is accompanied by activation of new slip systems. The observed disappearance of matrix components from the shear band microtexture is the result of twinning within reoriented matrix lamellae. In the twin-oriented areas, the dominance of one of two coplanar slip systems ultimately leads to the formation of the brass texture component.

The recrystallization mechanisms in high purity Ag crystals with C{112} initial orientation, deformed by channel-die compression, have been studied by local orientation measurements using TEM and SEM/EBSD. The microtexture analysis clearly indicates the importance of a simple relation of 25-40o ( or ) type, which is frequently observed during the early stages of recrystallization between isolated nuclei of uniform orientation and one of the as-deformed groups of components. As recrystallization proceeds, recrystallization twinning increases radically. In C-oriented silver single crystals this latter mechanism also plays a decisive role in the formation of the cube orientation.

The crystallography of recrystallization nucleation in high purity aluminium bicrystals, with boundary planes situated parallel to the compression plane, has been characterized in detail by microtexture analyses. The experiments were carried out on samples with 2 types of bicrystal orientations composed of the stable Goss{110} with an unstable cube{100} or shear{100} orientation. The bicrystals were cold deformed in channel-die compression up to true strains of 1.5. During recrystallization annealing, the deformation bands of the unstable orientations are the privileged sites for the formation of new grains. These nuclei were misoriented with respect to the orientations identified within the neighbouring deformed areas by α(, or ) relations. Growth of the new grains is always favoured along directions parallel to the traces of the {111} slip planes as shown in the stable and structurally homogeneous Goss {110} oriented grains. The grain boundary can play a role in recrystallization similar to that of the deformation bands.

The nucleation of recrystallized grains in deformed, high-purity aluminium were examined in relation to the microstructural heterogeneities in the form of shear bands (SBs) and transition bands (TBs). The experiments were carried out on single crystals deformed in channel-die compression at 77 K to true strains within the range of 1–1.5. The substructures were identified by means of a combination of transmission (TEM) and scanning (SEM) electron microscopes. Local texture measurements in particular places of samples were mostly investigated by means of TEM and convergent beam electron diffraction (CBED), with on-line diffraction pattern analysis. The coarser analyses were performed by SEM and electron back scattered diffraction (EBSD). The \({\rm C}\{112\} \langle 111 \rangle\) and the \({\rm S} \{531\} \langle 123 \rangle\) oriented single crystals are stable in the global sense and form clearly defined SBs. The \({\rm H} \{110\} \langle 110 \rangle\), and the ‘shear’ \(\{100\} \langle 011 \rangle\) orientations are very unstable and tend to form TBs. The nuclei of new grains formed along the band are misoriented by α (\(\langle 111 \rangle or \langle 112 \rangle\)) with respect to the orientations identified within the neighbouring banded material. The author attempts to explain, from the crystallographic point of view, the processes operating within high stacking fault energy metals at the very early stages of recrystallization.

The formation of brass-type shear bands (SB) in twinned microstructures of medium and low stacking fault energy (SFE) metal single crystals (copper, copper–2 wt.% aluminium and silver), with initial orientation {112}〈111〉 has been investigated after channel-die deformation at 77 and 293 K. The microstructures and local orientations were characterised over a wide range of scales by convergent beam electron diffraction in a transmission electron microscope, electron backscattered diffraction in a scanning electron microscope and optical metallography. For all metals it is shown that slip initially causes a general rotation to D(4 4 11)[11 11 8 ], which is then followed by partial twinning to the DT(26 26 5)[ 5 5 52] orientation. Subsequent shear banding of the unstable, layered, twin structure is responsible for the development of the strong Goss {110}〈100〉 orientation within the bands. A minor group of components is observed near {114}〈221〉, arising from the near primary matrix orientation. The intensity of mechanical twinning, and therefore, the relative amounts of primary matrix and twinned material, influences the SB internal microstructure. Alloys with low SFE such as Cu–2 wt.% Al deformed at 77 K twin almost completely whereas Cu at 77 K and Ag at 293 K retain significant quantities of (re-oriented) matrix and hence a relatively strong secondary microtexture component within the brass-type bands.

The nucleation of recrystallized grains in deformed, high-purity aluminium has been examined in relation to the microstructural heterogeneities in the form of shear bands (SBs). Low-temperature channel-die tests have been used to favour SB formation in single crystals with C{1 1 2}〈1 1 1〉 initial orientation, deformed at 77 K, and followed by the nucleation of recrystallization along these bands. The nuclei of the new grains formed along the band are systematically misoriented with respect to the orientations identified within the shear-banded material by 25–35° around the 〈1 1 1〉 axis. The author attempts to systematize, from the crystallographic point of view, the processes operating at the very early stages of the primary recrystallization of the metals with a high stacking fault energy.

W pracy przedstawiono wyniki prób związanych z doborem optymalnych parametrów procesu zgrzewania wybuchowego próbnych płyt z cyrkonu Zr 700 o grubości 10 mm ze stalą niestopową (P265GH). Do badań przygotowano układ bimetalowy Zr-stal oraz trimetalowy Zr-Ti-stal, w którym tytan jest międzywarstwą techno- logiczną ułatwiającą uzyskanie połączenia. Badania prowadzono dla złączy w stanie wyjściowym, tj. bezpo- średnio po zgrzewaniu wybuchowym. Poddano analizie zmiany strukturalne łączonych blach, ze szczególnym uwzględnieniem charakterystyki granicy połączenia. Wykonano badania właściwości mechanicznych otrzymanych platerów, tj. próbę ścinania, odrywania oraz zginania bocznego. Systematyczne pomiary rozkładu mikrotwardości umożliwiły analizę zjawiska umocnienia materiału w procesie zgrzewania wybuchowego, zarówno w strefie bezpośrednio przy granicy połączenia, jak i w całym przekroju plateru. Analiza uzyskanych wyników pozwoliła na ocenę wpływu zastosowania międzywarstwy technologicznej z czystego technicznie tytanu na jakość uzyskanego połączenia, tj. jego charakterystykę i właściwości wytrzymałościowe. Stwierdzono, że w przypadku platerowania cyrkonem o grubości 10 mm zastosowanie międzywarstwy technologicznej pozwala uzyskać połączenie o dobrych właściwościach mechanicznych i optymalnej charakterystyce granicy połączenia. Abstract The paper presents the results of trials aimed at selecting optimal settings of the explosion welding process of 10 mm thick zirconium (Zr 700) plates with carbon steel (P265GH). A bimetal Zr-steel and trimetal Zr-Ti-steel were prepared for testing purposes, where titanium serves as a technological intermediate layer facilitating the bonding. The research was carried out for as-bonded joints, i.e. immediately following explosion welding. Structural changes of the joined sheets underwent analysis, particularly focusing on the characteristic of the joint interface. Mechanical properties of the obtained cladders were tested with shearing, peel test and lateral bending test. Systematic measurements of microhardness distribution enabled analyzing the strengthening of the material resulting from explosion welding both at the bond interface zone and throughout the whole section of the clad. The resulting analysis enabled the assessment of the impact the application of the interlayer of pure titanium had on the quality of the bond, i.e. its characteristic and strength properties. It was established that during explosion welding with 10 mm zirconium the application of the interlayer allows obtaining a joint with good mechanical properties and optimal characteristic of the interface.

The texture of cold rolled and annealed cast strips of 70/30 brass was investigated. A delayed development of the main {110} component of brass type rolling texture was attributed to the intense deformation twinning which is associated with appearance of the strong {211} texture component at 50% reduction. The predominace of the {011} texture component in the range of 70%-90% reductions was related to the extensive shear banding. As for the rolling textures, the delay in development of the {236} component of brass type recrystallization texture was found.

The explosive welding technology is related to the dynamic impact of the clad onto base material. These results in significant microstructural changes of the bonded materials, the increase of internal stresses and the strain hardening of layers near the interface. In order to eliminate these unfavorable effects, it is advisable to carry out proper heat treatment. The paper presents the results of structural examinations and mechanical properties of bimetal zirconium - carbon steel, after long-lasting heat treatment. Bimetallic samples were annealed at 600 o C for 1, 10, 100, 500, 1000 hours. Microscopic examination were used to the analysis of microstructural changes, whereas systematic microhardness measurements and static tensile test to evaluation of the mechanical properties. It was found that the temperature has a beneficial effect on the changes in the bond zone and for longer annealing times a systematic decrease of the strength properties of the tested bimetal was observed. However, essential for the clad mechanical properties changes were observed in carbon steel plate. After short annealing (times of 1h and 10h) only small microstructural changes due to processes of recovery and recrystallization were observed in layers near the interface. The increase of annealing time was conducive to grain growth and carbon diffusion in the interfacial layer from steel towards zirconium.

Explosion welding of metals is a process of great technological significance in terms of modern metal composites manufacturing possibilities Nevertheless, selecting welding parameters is not an easy task. This paper assesses the effect of various values of distance of sheets on the quality of the bond zone in titanium (Ti Gr.1) - carbon steel (P355GH) structure. The research was carried out for initial state bonds i.e. immediately following explosion welding. The results of mechanical and structural investigations were presented. In order to determine changes in the value of strengthening, microhardness tests of both the weld and the joined plates were performed. Performed metallographic analysis shows that the standoff distance affects the quality of the bond zone boundary. Smaller distance promotes the formation of waves with lower parameters (of length and height), whereas greater distances allow forming the bond of a more pronounced, repetitive wavy character, however, increasing the quantity of the fusion zone at the same time. Also, the initial distance between the materials to be joined makes for the strengthening in the areas adjacent to bond boundary. The results received allowed to conclude that for the assumed parameters it is possible to obtain Ti -carbon steel bi-metal with properties meeting the standard’s requirements.

International audience; 6xxx aluminum alloys are widely used in the industry for their properties such as mechanical properties, corrosion resistance, weldability or good formability. Among the 6xxx aluminum alloys, the 6061 is one of the alloys most employed for structural application and is commonly welded. Welding is a joining operation which impairs base metal because of the high heat input used. It creates a zone where mechanical properties are different from the base metal which is called heat affected zone (HAZ). In the 6xxx aluminum alloy the HAZ is softer than base metal.

The development of macroscopic shear bands (MSB) in copper single crystal of (112)[ 1 1 1] orientation subjected to channel-die compression in liquid nitrogen is analysed. The influence of twinning on the local orientation inside MSB, defined by the position 011〈110〉 is demonstrated. The crystalographic nature of MSBs whose material shear plane is parallel to the plane 111 has been documented.

W artykule przedstawiono wyniki prób związanych z doborem optymalnych parametrów procesu zgrzewania wybuchowego próbnych płyt z cyrkonu Zr 700 z dwoma gatunkami stali: SA-516 Gr. 70 i 10CrMo9-10. Badania prowadzono dla złączy w stanie wyjściowym, tj. bezpośrednio po zgrzewaniu wybuchowym. Poddano analizie zmiany strukturalne łączonych blach, ze szczególnym uwzględnieniem charakterystyki granicy połączenia. Wykonano badania właściwości mechanicznych otrzymanych platerów, tj. próbę ścinania, odrywania oraz zginania bocznego. Systematyczne pomiary rozkładu mikrotwardości pozwoliły na analizę zjawiska umocnienia materiału w wyniku procesu zgrzewania wybuchowego, zarówno w strefie bezpośrednio przy granicy połączenia, jak również w całym przekroju plateru. Analiza uzyskanych wyników pozwoliła na ocenę wpływu parametrów procesu zgrzewania wybuchowego na jakość uzyskanego połączenia, tj. jego charakterystykę oraz właściwości wytrzymałościowe. Stwierdzono, że optymalne właściwości można uzyskać przy najniższych z zastosowanych parametrów procesu. The characteristic of zirconium-steel bimetalics strips fabricated by explosive welding using different process parameters The paper presents the results of trials aimed at selecting optimal parameters of the explosion welding process for test zirconium plates with two grades of steel – SA- 516 Gr 70 and 10CrMo9-10. The research was carried out for as-bonded welds, i.e. immediately following explosion welding. Structural changes of the joined sheets underwent analysis, particularly focusing on the characteristic of the bond boundary. Mechanical properties of the clads were tested by shearing, peel test and lateral bending. Systematic measurements of microhardness enabled analysing the strengthening of the material at the bond zone and throughout the whole section of the clad. The analysis make possible the description of the pro- cess parameters influence on the quality of the bond, i.e. its morphology and strength properties. It was concluded that the optimal properties of the clad can be achieved with the lowest values of the process parameters.