Crystalline Evolutions in Chessboard-like Microstructures

We describe the macroscopic behavior of evolutions by crystalline curvature of planar sets in a chessboard--like medium, modeled by a periodic forcing term. We show that the underlying microstructure may produce both pinning and confinement effects on the geometric motion.Comment: 17 pages, 10 figures. arXiv admin note: text overlap with arXiv:1707.0334

Research progress on selective laser melting (SLM) of bulk metallic glasses (BMGs):a review

Bulk metallic glasses (BMGs) are a subject of interest due to their superior specific properties such as low coefficient of friction, high strength, large ductility in bending, high elastic modulus, high microhardness, and high resistance to corrosion, oxidation, wear, and so on. However, BMGs are difficult to apply in industry due to their difficulty in manufacturing and secondary operation. In the past few decades, many efforts have been carried out to overcome the defects in the manufacturing of BMGs. It is difficult to fabricate complex structures with the whole amorphous alloy owing to the limit of crystallization and critical cooling rate. Additive manufacturing (AM), such as selective laser melting (SLM), can obtain relatively high cooling rates during the “layer-by-layer” process, which makes it possible to surpass the dimensional limitation of metallic glass. In the SLM process, the high-speed cooling of molten pool and the avoidance of secondary processing are very beneficial to the production and application of amorphous alloys. In this paper, based on the research of SLM additive manufacturing BMGs in recent years, the factors affecting crystallization and forming ability are discussed from many aspects according to different material systems. The status and challenges of SLM manufacturing BMGs including Fe-based, Zr-based, Al-based, and some composite-based BMGs will be presented. Mechanical properties and physicochemical properties were introduced. This review aims to introduce the latest developments in SLM additive manufacturing BMGs, especially on the development of process parameters, structure formation, simulation calculation, fracture mechanism, and crystallization behavior. With the traditional fabricating methods, BMGs were mainly used as a structure material. It will provide another alternative to use BMGs as a functional material by introducing SLM technology in amorphous preparation with complex geometry. This review summarizes the technical difficulty and application prospects of BMGs preparation by SLM and discusses the challenges and unresolved problems. This review identifies key issues that need to be addressed in this important field in the future. These problems are related to the application of BMGs as high-strength structural materials and new functional materials in the future

Laser-based Additive Manufacturing of Bulk Metallic Glasses: Recent Advances and Future Perspectives for Biomedical Applications

Bulk metallic glasses (BMGs) are non-crystalline class of advanced materials and have found potential applications in the biomedical field. Although there are numerous conventional manufacturing approaches for processing BMGs, the most commonly used like copper-mould casting have some limitations. It is not easy to manage and control the critical cooling rate, especially when the fabrication of complex BMG geometries is involved. Other limitations of these techniques include the size constraints, non-flexibility, and the tooling and accessories are costly. The emergence of additive manufacturing (AM) has opened another promising manufacturing route for processing BMGs. AM processes, particularly laser powder-bed fusion (PBF-LB/M) builds parts layer-by-layer and successively fused the powder-melted feedstocks using prescribed computer-controlled laser scanner system, thereby forming a BMGs part upon sufficiently rapid cooling to ensure the glass forming-ability. PBF-LB/M overcomes the limitations of the pre-existing BMGs processing techniques by not only improving the part size, but also produces exceptionally complex structures and patient-specific implants. This review article aims to summarise and discuss the mechanism of BMGs formation through PBF-LB/M for biomedical applications and to highlight the current scientific and technological challenges as well as the future research perspectives towards overcoming the pore-mediated microcracks, partial crystallisation, brittleness and BMG size constraint

Selective laser melting of glass-forming alloys

Bulk metallic glasses (BMGs) are known to have various advantageous chemical and physical properties. However, the condition of producing BMGs is critical. From a melt to congealing into a glass, the nucleation and growth of crystals has to be suppressed, which requires a fast removal of the heat. Such high cooling rates inevitably confine the casting dimensions (so-called critical casting thickness). To overcome this shortcoming, additive manufacturing proves to be an interesting method for fabricating metastable alloys, such as bulk metallic glasses. Selective laser melting (SLM), one widely used additive manufacturing technique, is based on locally melting powder deposited on the powder bed layer by layer. During the SLM process, the interaction between laser beam and alloys is completed with a high energy density (105 - 107 W/cm2) in very short duration (10-3 - 10-2 s), which results in a high cooling rate (103 - 108 K/s). Such high cooling rates favour vitrification and to date, various glass-forming alloys have been prepared. The approach to prepare bulk metallic glasses (BMGs) by SLM bears the indisputable advantage that the size of the additively manufactured glassy components can exceed the typical dimensions of cast bulk metallic glasses. Simultaneously, also delicate and complex geometries can be obtained, which are otherwise inaccessible to conventional melt quenching techniques. By using such advantages of SLM, Ti47Cu38Zr7.5Fe2.5Sn2Si1Ag2 (at.%) and Zr52.5Cu17.9Ni14.6Al10Ti5 (at.%) BMGs have been successfully fabricated via SLM in the current work. The SLM process yields material with very few and small defects (pores or cracks) while the conditions still have to render possible vitrification of the molten pool. This confines the processing window of the fully amorphous SLM samples. By additively manufacturing different BMG systems, it is revealed that the non-linear interrelation is differently pronounced for varied compositions. The only way to obtain glassy and dense products is optimizing all the process parameters. However, it is difficult to obtain fully dense sample (100%). The relative density of the additively manufactured BMGs can reach 98.5% (Archimedean method) in current work. The residual porosity acts as structural heterogeneities in the additively manufactured BMGs. The structures of BMGs are sensitive to the thermal history, i.e. to the cooling rate and to the thermal treatment. During SLM process, the laser beam not only melts the topmost powder, but also the adjacent already solidified parts. Such complicated thermal history may lead to locally more/less relaxed structure of the additively manufactured BMGs. Thus, systematic and extensive calorimetric measurements and nanoindentation tests were carried out to detect these structural heterogeneities. The relaxation enthalpies, which can reveal the free volume content and average atomic packing density in the additively manufactured BMGs are much higher than that in the as-cast samples, indicating an insufficient duration for structural relaxation. The nanoindentation tests indicate that the structure of additively manufactured BMG is more heterogeneous than that of as-cast sample. Nevertheless, no obvious heat-affected zone which corresponds to the more/less relaxed structure is visible in the hardness map. In order to reveal the origin of such heterogeneity, the thermal field of the additively manufactured BMGs was simulated via finite volume method (FVM). Owing to the different process parameters and varied thermophysical properties of Ti47Cu38Zr7.5Fe2.5Sn2Si1Ag2 and Zr52.5Cu17.9Ni14.6Al10Ti5 BMGs, the heat-affected zone (HAZ) is differently pronounced, resulting in the varied heterogeneities of both additively manufactured BMGs. Afterwards, the physical and chemical properties of the additively manufactured BMGs were systematically studied. The additively manufactured BMGs tend to fail in a premature manner. The heterogeneities (defects, crystalline phases and relaxed/rejuvenated regions) can determine the mechanical and chemical properties of the BMGs. In the current work, the additively manufactured BMGs are fully amorphous. Thus, the effects of crystalline phases can be ruled out. The effect of residual porosity and more/less relaxed state on the deformation of additively manufactured and as-cast BMGs has been studied. The analysis of the observed serrations during compressive loading implies that the shear-band dynamics in the additively manufactured samples distinctly differ from those of the as-cast glass. This phenomenon appears to originate from the presence of uniformly dispersed spherical pores as well as from the more pronounced heterogeneity of the glass itself as revealed by instrumented indentation. Despite these heterogeneities, the shear bands are straight and form in the plane of maximum shear stress. Additive manufacturing, hence, might not only allow for producing large BMG samples with complex geometries but also to manipulate their deformation behaviour through tailoring porosity and microstructural heterogeneity. Different from the compressive tests, the heterogeneities of additively manufactured BMGs have no significant effect on the tribological and corrosion properties. The similar specific wear rate and the worn surfaces demonstrate that similar wear mechanisms are active in the additively manufactured and the as-cast samples. The same holds for the corrosion tests. The anodic polarization curves of SLM samples and as-cast samples illustrate a similar corrosion behaviour. However, the SLM samples have a slightly reduced susceptibility to pitting corrosion and reveal an improved surface healing ability, which might be attributed to an improved chemical homogeneity of the additively manufactured BMGs. In order to improve plasticity, bulk metallic glasses composites (BMGCs) have been developed, in which crystals precipitate in a glassy matrix. The crystalline phases can alter the local stress state under loading, thereby, impacting the initiation and propagation of the shear bands. However, it is difficult to control the crystalline volume fraction as well as the size and spacing between the crystals by using the traditional melt-quenching method. One approach is to mix glass-forming powder with conventional alloy powder. In this way, a large degree of freedom for designing the microstructure can be gained. Thus, SLM was chosen to prepare such “ideal” BMGCs in the present work. The β-phase stabilizer Nb powder was mixed with Zr52.5Cu17.9Ni14.6Al10Ti5 powder. After SLM processing, the irregular-shaped Nb particles are distributed uniformly within the glassy matrix and bond well to it. At the higher Nb content, diffusion of Nb during processing locally deteriorates the glass-forming ability of the matrix and results in the formation of several brittle intermetallic phases around the Nb particles. The size of these precipitates covers a wide range from nanometres to micrometres. Despite the fact that the soft Nb particles increase the heterogeneity of the glassy matrix, none of the samples deforms plastically. This is attributed to the network-like distribution of the intermetallic phases, which strongly affects the fracture process. Besides the ex-situ method of mixing powders, designing in-situ ductile phases and controlling the fraction of the crystalline phases by altering process parameters can also prepare optimized BMGCs. Cu46Zr46Al8 (at.%) was processed via SLM to produce in-situ BMGCs. It is revealed that the microstructure of the nearly fully dense additively manufactured BMGs is strongly affected by the energy input. By increasing the energy input, the amount of the crystalline phases was raised. By optimizing the energy input, the B2 CuZr phase was particularly deliberately introduced. Due to the residual porosity and brittle phases, no plasticity is visible in the additively manufactured samples. Generally, selective laser melting opens a gateway to design the microstructure of the BMG matrix composites.:Abstract I Kurzfassung IV Symbols and abbreviations VIII Aims and objectives VIII CHAPTER 1 Metallic glasses and selective laser melting 1 1.1 Formation of metallic glasses from the melt 1 1.2 Mechanical properties of BMGs and their composites 4 1.2.1 Shear banding in metallic glasses 4 1.2.2 Effect of structural heterogeneities on plastic deformation 7 1.2.2.1 Nanoscale heterogeneities 8 1.2.2.2 Microscale heterogeneities 11 1.2.3 Shear band dynamics 13 1.2.4 Tribological properties of BMGs 15 1.3 Corrosion behaviour of bulk metallic glasses 16 1.4 Selective laser melting (SLM) 20 1.4.1 The SLM process 20 1.4.1.1 Powder properties 21 1.4.1.2 Process parameters 22 1.4.2 Solidification and thermal history 25 1.5 Selectively laser-melted glass formers 28 1.5.1 Selective laser melting of a single alloy powder 28 1.5.2 Heterogeneities and mechanical properties of additively manufactured BMGs 32 CHAPTER 2 Experimental 36 2.1 Sample preparation 36 2.1.1 Arc melting 36 2.1.2 Suction casting 36 2.1.3 Gas atomization 37 2.1.4 Powder mixtures 37 2.1.5 Selective laser melting (SLM) 38 2.1.5 Heat treatment 39 2.2 Sample characterization methods 39 2.2.1 Composition analysis 40 2.2.2 X-ray diffraction 40 2.2.3 Calorimetry 40 2.2.4 Density measurements (Archimedean method) 41 2.2.5 µ-CT 41 2.2.6 Scanning electron microscopy (SEM) 41 2.2.7 Transmission electron microscopy (TEM) 42 2.2.8 Hardness measurements 42 2.2.9 Compression tests 43 2.2.10 Sliding wear tests 43 2.2.11 Corrosion tests 44 2.2.12 Finite volume method modelling 45 CHAPTER 3 Selective laser melting of glass-forming alloys 46 3.1 Selective laser melting of a Ti47Cu38Zr7.5Fe2.5Sn2Si1Ag2 BMG 46 3.1.1 Powder analysis 47 3.1.2 Parameter optimization and microstructural characterization 48 3.1.3 Mechanical properties 55 3.1.3.1 Compression tests 55 3.1.3.2 Microhardness and structural relaxation 57 3.1.3.3 Nanoindentation 59 3.1.4 Corrosion properties 61 3.2 Selective laser melting of a Zr52.5Cu17.9Ni14.6Al10Ti5 BMG 62 3.2.1 Powder analysis 62 3.2.2 Microstructural characterization 63 3.2.3 Mechanical properties 66 3.2.3.1 Compression tests 66 3.2.3.2 Microhardness and structural relaxation 68 3.2.3.3 Nanoindentation 71 3.2.4 Shear band dynamics and shear band propagation 74 3.2.5 Tribological and corrosion properties 80 3.3 Structural heterogeneities of BMGs produced by SLM 87 CHAPTER 4 Selective laser melting of ex-situ Zr-based BMG matrix composites 97 4.1 Phase formation 97 4.2 Microstructures 101 4.3 Mechanical properties 110 CHAPTER 5 Selective laser melting of in-situ CuZr-based BMG matrix composites 115 5.1 Powder analysis 115 5.2 Parameter optimization 116 5.3 Microstructure 120 5.4 Mechanical properties 124 5.4.1 Compression tests 124 5.4.2 Microhardness and structural relaxation 127 5.4.3 Nanoindentation 129 CHAPTER 6 Summary 132 CHAPTER 7 Outlook 132 Acknowledgements 137 Bibliography 139 Publications 163 Eidesstattliche Erklärung 16

Methodology for Shot-Peening Induced Intragranular Residual Stress Prediction

Résumé Le grenaillage est un traitement mécanique des surfaces qui consiste à projeter des billes à très haute vitesse à la surface d’une pièce. Ce traitement est utilisé depuis plus d’une soixantaine d’année dans l’industrie pour améliorer la durée de vie en fatigue des matériaux par l’introduction de contraintes résiduelles de compression et de gradients de duretés en sous surface. Le procédé a longtemps été simplement considéré comme bénéfique sans réelle quantification des bénéfices apportés sur la durée de vie en fatigue et les évolutions de microstructures. En effet, modéliser le procédé a longtemps été un verrou car cela implique de simuler un grand nombre d’impacts, de reproduire avec précision la cinétique des billes et de prendre en compte un certain nombre de non-linéarités dues au contact et aux déformations plastiques. Cependant les avancées de ces dix dernières années ont permis le développement de modèles pouvant prédire avec précision le profil moyen de contraintes résiduelles en profondeur ainsi que les gradients d’écrouissage résultants. Peu d’études ont cependant tenté de prédire les contraintes résiduelles et l’écrouissage induits à l’échelle d’un grain. Les variations intragranulaires des contraintes ont pourtant une influence sur la durée de vie à grand nombre de cycle d’un matériau. Par ailleurs l’écrouissage local constitue une donnée cruciale pour certains modèles de prédiction de durée de vie en fatigue. Les verrous principaux à lever pour effectuer de telles prédictions sont l’identification précise de modèles de plasticité cristalline à l’échelle de la surface et dans les conditions du procédé, ainsi que le développement de méthodes expérimentales de validation des modèles développés. L’objectif de cette thèse est de développer une méthodologie pour la prédiction des contraintes résiduelles et de l’écrouissage intragranulaire à l’aide de modèles de plasticité cristalline par éléments finis et de validations expérimentales. Des essais d’indentation sphérique sur des monocristaux de cuivre sont présentés afin d’estimer le champ de contrainte induit en sous surface expérimentalement et numériquement. Les résultats révèlent que l’anisotropie de la plasticité cristalline peut induire des contraintes résiduelles de tension en sous surface. La comparaison des champs numériques et expérimentaux confirme aussi la possibilité de comparer des champs de contraintes estimés par EBSD à haute résolution à ceux prédits par des modèles de plasticité cristalline de façon suffisament quantitative pour permettre la validation de modèle. Les évolutions microstructurales induites par le grenaillage d’un coin sont ensuite étudiées par des estimations EBSD de densités de dislocations géométriquement nécessaires à l’aide de nouvelles méthodes d’indexation alternatives. Les différences d’écrouissage relevées démontrent l’importance de modéliser le procédé à l’échelle du grain. Une méthodologie pour l’identification de loi de plasticité cristalline à haute vitesse basée sur des essais de microcompression est détaillée. Une attention particulière à été portée sur le caractère bien posé du problème d’identification, à l’aide d’indice d’identifiabilités. Un canon a grenailler capable de projeter des billes isolées avec une large gamme de vitesse et une haute précision a été développé pour valider le modèle. Un code a été implémenté pour estimer la trajectoire de la bille en trois dimensions avec une précision de 200 μm pour servir d’entré aux modèles éléments finis. La validation du modèle précédent est effectuée par comparaison du déplacement de la bille, de la topologie de l’empreinte d’impact et du champ de désorientation sous l’empreinte estimés expérimentalement et numériquement. Enfin la possibilité d’utiliser le déplacement de la bille et le champ de contraintes résiduelles induit par un impact est explorée par une étude d’identifiabilité détaillée. Ces travaux offrent de nouveaux outils et méthodologies pour l’identification de paramètres et la validation de modèles à l’échelle du grain et à haute vitesse. ---------- Abstract Shot peening is a mechanical surface treatment which consist in projecting several spherical particles onto a material’s surface. The process have been widely used in the industry over more than sixty years to enhance material’s fatigue properties by introduction of subsurface compressive stresses and hardening gradients. It has been long used as a ’nice to have’ without any quantification of its benefits as its modeling involved a large number of impacts, complex shot kinematics and non linearities induced by contact and plastic deformations. Nonetheless, advances over the past twenty years provided models that successfully reproduced experimentally measured average residual stress profiles and hardening gradients. However, only few attempts to predict the residual stress and hardening variations at the grain scale have yet been reported. Intragranular stress variations could influence a structure high cycle fatigue behaviour and local hardening could be a crucial input for fatigue life predictions models. The main barriers to achieve such predictions are mainly the difficulty to identify accurate crystal plasticity models in the process conditions as well as defining relevant validation procedures to assess the ability of the models to predict residual stress variations. The objective of this thesis is to develop a methodology for shot peening induced intragranular residual stress and hardening prediction using crystal plasticity finite element simulations and experimental validations. Indentation on single crystal copper are first presented to assess the residual stress variations in a single grain under the indent both experimentally and numerically. The results reveal that crystal plasticity anisotropy could induce subsurface tensile residual stresses under a spherical contact. It also demonstrates that experimental residual stress fields estimated by high angular resolution electron backscattered diffraction could be quantitatively compared to finite element models. This finding makes it a relevant tool for constitutive behaviour validation. The microstructural evolutions induced by shot peening of a corner are investigated using electron backscatter diffraction geometrically necessary dislocation estimations with recently developed alternative indexation methods. The differences in hardening gradient close to the corner compared with a reference shot peened material evidences that accurately predict microstructural evolutions induced by the process at the grain scale is necessary to predict the induced hardening distribution. These works provides new evidences of the relevance of modeling the process at the crystal scale. A methodology for identification of crystal plasticity parameters at high strain rates using micropillar compression is then detailed. Particular attention is paid to the identification problem well-posedness using identifiability indicators provided by the literature. A shotpeening canon that can propel single shot over a wide velocity range with high aiming precision is developed. An in-house code that can estimate the shot trajectory within 200 μm is implemented to provide input for finite element analyses. The setup is used for validation of the previously identified model by comparison of the shot displacement impact dent topography and in-depth crystal misorientation field. Finally, the possibility to use the shot displacement curve and residual stress field under the dent produced by the setup is investigated through a detailed identifiability analyses. These works provide new tools and methodologies for crystal plasticity parameters identification and validation at the grain scale and at high strain rates

Modélisation et simulation du couplage changement de phases-mécanique par la méthode des champs de phases

A general constitutive framework is proposed to incorporate linear and nonlinear mechanical behaviour laws (i.g. elastoviscoplasticity) into a standard phase field model. A finite element formulation of a coupled phase field/diffusion/mechanical problem for alloys is proposed within the general framework of continuum thermodynamics. This formulation is based on the concept of generalized stresses as proposed by Gurtin, where an additional balance equation for generalized stresses, called microforces, associated with the order parameter and its first gradient, is postulated. The formulation is used to simulate the complex morphological evolutions of the heterogeneous microstructures and to describe the diffuse interface between two phases in the presence of the stresses induced by phase transformation. Using the principles of the thermodynamics of irreversible processes, the balance and constitutive equations are clearly separated in the formulation. Also, boundary and initial conditions for the displacement, concentration and order parameter and their dual quantities are clearly stated within the formulation. The theory is shown to be well-suited for a finite element formulation of the initial boundary value problems on nite size specimens with arbitrary geometries and for very general non-periodic or periodic boundary conditions. In the diffuse interface region where both phases coexist, mixture rules taken from homogenization theory are introduced into the formulation. The consequences of the choice of a specific interface behaviour is investigated, with regard to the mechanical effect on phase equilibria (equilibrium compositions and volume fractions of the coexisting phases), as well as on the transformation kinetics. The set of coupled evolution equations, which are the local static equilibrium, the balance of generalized stresses and the balance of mass, is solved using a finite element method for the space discretization and a finite difference method for the temporal discretization. To validate the numerical finite element implementation and to illustrate the ability of the proposed model to handle precipitation together with mechanical contribution effect, some elementary initial boundary value problem in coupled diusion-elasto-plasticity on finite size specimens has been solved and validated against corresponding sharp interface analytical solutions.Nous proposons un cadre générique, permettant l'incorporation des différentes lois de comportement de mécanique linéaires ou non-linéaires (i.e. elastoviscoplastique) dans les approches des champs de phases utilisées pour la modélisation et la simulation de la mobilité d'interfaces diffuses. Dans ce cadre, une formulation par éléments finis des modèles couplés champ de phases-élastoplasticité pour les alliages binaires est développée dans le formalisme général de la thermodynamique des milieux continus. Cette formulation est basée sur la théorie d'équilibre des microforces, proposée par Gurtin, où une équation supplémentaire, fonction du paramètre d'ordre et de son gradient, est introduite. La formulation est employée pour simuler les évolutions morphologiques complexes des microstructures hétérogènes et décrire l'interface diffuse entre deux phases en présence des contraintes induites par transformation de phase. En utilisant les principes de la thermodynamique des processus irréversibles, les lois de comportement et les équations d'évolution sont clairement exposées et séparées dans la formulation de sorte que des modèles non-linéaires et fortement couplés puissent être implantés plus facilement dans un code par éléments finis. Cette formulation peut être appliquée aux corps finis périodiques et non périodiques, aux microstructures hétérogènes. Les conditions initiales et les conditions aux limites en paramètre d'ordre et en concentration ainsi que leurs quantités duales sont clairement énoncées. Des techniques d'homogénéisation ont été utilisées pour décrire le comportement dans les interfaces diffuses. Les conséquences de ces choix de modélisation ont été déterminées en ce qui concerne les effets des contraintes mécaniques sur les équilibres de phases et la cinétique de transformation. L'ensemble des équations d'évolution couplées, à savoir l'équation d'équilibre statique local, l'équation de champ de phases et l'équation de conservation de la masse, est résolu en utilisant la méthode des éléments finis pour la discrétisation spatiale et un schéma implicite des différences finies pour la discrétisation temporelle. Afin d'illustrer l'intérêt de l'approche proposée, des calculs par éléments finis ont été effectués sur des situations élémentaires telles que le calcul des concentrations d'équilibre des phases en présence de contraintes et la croissance de précipités dans une matrice élastique ou élasto-plastique, situations pour lesquelles des solutions analytiques pour des interfaces parfaites sont disponibles

Long-term activity of shear zones in the Dom Feliciano Belt and associated terranes (South America)

The Dom Feliciano Belt in southern Brazil and Uruguay records the superposed tectonic events that led to the assembly of southwestern Gondwana during the Neoproterozoic Brasiliano-Pan-African orogenic cycle. During the course of the orogeny, the belt and associated Precambrian domains were affected by widespread crustal deformation, leading to a complex set of shear zones. This thesis investigates the tectono-thermal history of the main shear zones in the Dom Feliciano Belt and associated terranes. Deformation conditions and the evolution of the shear zones are characterized using structural and microstructural observations, combined with quartz CPO textural analyses. New K-Ar data and a review of the literature are used to constrain this evolution in the geochronological timescale. In addition, the Phanerozoic thermal history of the study area is investigated combining (U-Th)/He analyses on zircon and apatite, thermal modelling, and K-Ar dating of fault gouges. In this way, it is possible to examine the impact of the main Neoproterozoic structures as preferential sites for reactivation. The oldest terrane boundary in the region is the Ibaré Shear Zone, which records the accretion of the Tonian juvenile São Gabriel Terrane to the Archean-Paleoproterozoic Nico Pérez Terrane as a dextral lateral ramp during SW-verging thrusting. New-K-Ar analyses suggest that it was established at ca. 760 to 740 Ma, and reactivated in the Cryogenian-Ediacaran in narrow sinistral shear zones at cooler conditions, during the formation of the Dom Feliciano Belt. The belt was formed during oblique collision between the Congo and Río de la Plata cratons, together with the Nico Pérez and Luís Alves Terranes, resulting in widespread transpression. This process was probably diachronic, with onset of transcurrent structures being recorded between ca. 650 and 620 Ma in different sectors of the belt, and led to the formation of its main terrane boundary, the Major Gercino-Dorsal do Canguçu-Sierra Ballena lineament. This shear zone system records an intense amount of pure shear and contrasting kinematics along its extension, suggesting local variations to the main horizontal compression and partitioning into different transcurrent vectors. After 600 Ma there is a decrease in wide-scale regional compression, transitioning to localized strike-slip deformation along the main shear zones, suggesting a post-collisional stage. Late ductile reactivations were active until ca. 540-530 Ma. With the cessation of the orogenic processes, the study area stabilized and achieved an intracratonic position inside Gondwana, experiencing a protracted evolution during the Phanerozoic. Exhumation during the early Paleozoic probably exposed much of the present-day crystalline basement to near-surface conditions, and was followed by regional subsidence during the sedimentation of the Paraná Basin. For most of the belt’s extension, final exhumation was achieved at the latest during the rift stage of the South Atlantic in the Lower Cretaceous, but its northernmost portion records up to 2 km of post-rift exhumation. While recurrent brittle reactivation of Neoproterozoic structures is recorded by the dating of fault gouges, this process is not reflected in the study area’s thermal history. Instead, the main structural control is by transecting fault systems, oriented perpendicular to the South Atlantic coastline. Along the south-southeastern South American passive margin, major reactivation of the inherited structures is predominantly recorded in strongly uplifted regions