Copper based alloys play important role in high heat flux applications, particularly in rocket technology, the liner of the combustion chamber, and also in other heat transfer vessels. In these applications, one needs excellent high-temperature strength without sacrificing the thermal conductivity significantly. However, it is a challenging and difficult task to significantly improve the balance between strength and conductivities (electrical and thermal) of Cu-based alloys. In general, microstructural attributes, responsible for increasing mechanical strength of the alloy, also affect the transport properties by creating scattering centers. Hence, delicate optimization is needed for developing balanced alloy system for better performance. A substantial amount of research efforts has therefore been focused on devising methodologies to synthesize copper based alloys with a good combination of strength and conductivity. The present thesis deals with the development of a newer class of high strength high conductivity copper base alloy through tuning of phase transformation and careful additions of ternary and quaternary alloying elements and ultimately by microstructural engineering. In this thesis, we report the development of novel high strength high conductivity Cu-based alloy series in the Cu-Fe-Si system through rapid solidification process using suction casting apparatus. We have also optimized the alloys by altering and fine tuning the alloy compositions in order to achieve balanced and optimum properties. The strength of copper can be increased by various strengthening mechanisms. In general, precipitation hardening, dispersion strengthening and solid solution strengthening are the three most effective mechanisms for improving the strength of copper. Among these, solid solution strengthening has the most detrimental effect on the transport properties due to the presence of solute atoms which act as prominent scattering centres. Precipitation hardened copper alloys are often unable to retain strength at high temperatures, due to the coarsening of the precipitates. Currently, efforts are being made to develop newer dispersion strengthened copper alloys. These alloys contain a fine dispersion of nanometer sized oxides or other intermetallic compounds in the copper matrix. Dispersion strengthened copper alloys show impressive mechanical strength as well as thermal stability. In this thesis, we have explored the possibility of obtaining structurally ordered intermetallic dispersions through exploiting immiscibility of solutes in copper based alloys. The immiscibility promotes precipitation and decrease the solid solubility of solute elements in the matrix which in turn minimizes the scattering process and thus offers the possibility of improved transport properties. These ordered and coherent dispersion of intermetallic particles in the continuous copper matrix, dispersed during solidification, are believed to be the main contributor to the improvement of mechanical strength of the alloy. Crystallographically ordered structure and the coherency strain associated with the intermetallic particles in the copper matrix, together contribute to the mechanical strength through the mechanism of order hardening and coherency strengthening. These also, promote a low interfacial energy between precipitates and matrix in the alloy. This low interfacial energy reduces the driving force for coarsening process and thus helps in retaining the mechanical strength at elevated temperatures. Releasing of coherency strain at the precipitate-matrix interface with increasing temperature also yields a dramatic effect on the enhancement of thermal conductivity at high service temperatures. In the current study, we have selected three alloy compositions in the Cu-Fe-Si system at the higher end of copper. These are Cu-20Fe-5Si (at%), Cu-2.5Fe-2.5Si (at%) and Cu-1.0Fe-1.0Si (at%) respectively. We have systematically increased the concentration of copper, and altered the ratio of Fe and Si in order to achieve the better combination of properties (mechanical and transport) through fine tuning the microstructure. The present sets of alloys have been chill cast by the suction casting technique. This rapid solidification process, associated with moderate undercooling, is capable of accessing the submerged metastable miscibility gap of the Cu-Fe binary system. The higher quenching rate moves the system far away from equilibrium and hence, the solidification process occurs at the non-equilibrium regime. Rapid solidification of a copper rich Fe-Cu melt promotes the precipitation of the γFe from copper solid solution due to the immiscibility of Fe and Cu. In this scenario, the addition of a small quantity of silicon as a ternary element leads to its partition to both copper and iron rich phases. However, the larger chemical affinity between Fe and Si, leads to the formation of an ordered structure. However, the FCC crystal field of the copper matrix tends to promote an FCC based novel L12 ordered structure of the Fe3Si intermetallic particles instead of the ordered DO3 structure of Fe3Si composition normally observed in the bulk alloy. This nano meter sized L12 ordered particles maintain a cube-on-cube orientation relationship with the surrounding copper matrix and are associated with large coherency strain. A good lattice matching between these L12 ordered particles and copper matrix will promote a low interfacial energy and thus, a low driving force for particle coarsening. The present thesis is divided into eight chapters. The first chapter introduces the present work and the organization of the thesis. In the second chapter, current status in the development of the copper alloys and the general principle of alloy developments has been described. This includes both experimental and theoretical developments that can be used for developing high strength Cu based alloys. Chapter three, titled as „experimental procedure‟, describes the detailed description of materials and experimental techniques, adopted for the current studies. There are three chapters that deal with the main results of the thesis. Chapter eight, describes the suggestion for future work. The fourth chapter, titled as „Chill cast Cu75Fe20Si5 alloy: Microstructural Evolution and Properties‟, explores the detailed microstructural evolution of the Cu75Fe20Si5 alloy. This chapter also discusses the microstructure-property correlations. The microstructure of the alloy exhibits a multi-scale hierarchical structure during rapid solidification. The solidified microstructure contains Fe-rich globules with DO3 ordered structure, embedded in the continuous Cu-rich matrix. The continuous copper matrix also contains nanometer sized (average diameter 12 nm) coherent particles that exhibit Ashby-Brown strain contrast. Characterization of these phases has been carried out by a combination of X-ray diffraction, electron probe microanalysis and transmission electron microscopy coupled with energy dispersive spectroscopy. This multi-scale complex copper alloy (Cu75Fe20Si5 ) has achieved a remarkable yield and ultimate tensile strength at both room temperature and elevated temperatures in comparison to other copper based alloys. The yield strength and ultimate tensile strength at room temperature are 516±17 MPa and 635±14 MPa respectively whereas yield strength and ultimate tensile strength at 6000C turn out to be 95±11 MPa and 105±12 MPa respectively. In spite of achieving good mechanical strength, this alloy suffers from deterioration of electrical and thermal conductivity due to the presence of high volume fraction of the second phase and alloying elements. The room temperature electrical resistivity of this alloy shows that it is 10 times higher than that of pure copper (alloy resistivity = 1.70E-05 Ohm-cm at 250C and pure Copper- 1.68 × 10-6 Ohm-cm at 200C ). The thermal conductivity of this alloy turns out to be 88 W/m.K at 500C and 161 W/m.K at 6000C respectively which is much smaller in comparison to pure copper ( pure copper ≈ 401 W/m.K at 50 to 6000C). Attempts have been made to overcome the lowering of the transport properties by careful alteration of alloy compositions and fine tuning the microstructure. A new alloy with composition Cu-2.5Fe-2.5Si (at %) has been synthesized in order to achieve better transport properties without significantly sacrificing the mechanical strength. In this new alloy, we have reduced the volume fraction of the second phase (Fe-rich DO3 ordered globules) by lowering the addition of the alloying elements. We have also tried to alter the Fe to Si ratio in such a way that we can retain nanometer sized coherent particles in the matrix that provides strengthening. We arrived at a Fe and Si atom ratio of 1:1. The study of this alloy is presented in chapter five titled as „Chill cast Cu95Fe2.5Si2.5 alloy: Microstructural Evolution and Properties‟. Microstructural characterization indicates that the alloy contains only the nano meter sized coherent L12 ordered particles in the copper matrix. These particles show the Ashby-Brown strain contrast and are rich in iron and silicon. The absence of the high volume fraction of DO3 ordered Fe-rich globular phase and the smaller addition of the alloying elements ensure an improvement in the transport properties. The average resistivity value of this alloy at 250C is 3.5053 × 10-6 (Ohm-cm). This value represents a dramatic improvement in electrical properties in comparison to the Cu75Fe20Si5 alloy (Cu75Fe20Si5 alloy: 1.70E-05 Ohm-cm at 250C). The result is even better when we consider the temperature dependent thermal conductivity of the Cu95Fe2.5Si2.5 alloy. The thermal conductivity of this alloy turns out to be 236 W/m.K at 500C and 313 W/m.K at 6000C respectively. Though the thermal conductivity at room temperature is lower than pure copper, the gap reduces with increasing temperature (pure copper ≈ 401 W/m.K at 50 to 6000C and Cu75Fe20Si5 alloy: 88 W/m.K at 500C and 161 W/m.K at 6000C). This trend of temperature dependent thermal conductivity has made this alloy as one of the potential candidates for high-temperature applications. In situ heating experiment using transmission electron microscope (up to 4500C) and the heat treatment analysis at 6000C confirm that these L12 ordered particles are structurally stable at high temperatures and believed to be the main contributor to high mechanical strength in the alloy through the mechanism of order hardening and coherency strengthening. Coherent nature of the interface between the ordered particles and copper matrix also promotes low interfacial energy in the alloy and thus offers resistance to coarsening at elevated temperatures. Along with the attractive transport properties, this alloy also exhibits its success of retaining mechanical strength at both ambient and high temperatures as compared to the earlier alloy. The room temperature yield strength and ultimate tensile strength of this alloy are recorded as 580±18 MPa and 690±16 MPa respectively whereas the yield strength and ultimate tensile strength at 6000C of this alloy obtained as 128±8 MPa and 150±10 MPa respectively. Thus newly modified alloy exhibits an excellent balance between mechanical strength and conductivity (electrical and thermal) and can be regarded as a promising alloy for high strength high heat flux applications. The possibilities of the Cu95Fe2.5Si2.5 alloy as a potential candidate for high strength high conductivity application has provided the motivation for further optimization of the composition of this class of alloy. Mechanical strength and transport properties of a precipitation strengthened alloy always depends on the structure, shape, volume fractions and the number densities of the precipitate particles. Electrical and thermal conductivity are also sensitive to the presence of third elements and the number densities of the precipitates in the alloy. Thus, optimization of the volume fraction and the number density of the precipitates can yield a better alloy. With this objective, we have further increased the concentration of copper while keeping the Fe and Si atom ratio fixed at 1:1. Chapter six, titled as „Chill cast Cu98Fe1.0Si1.0 alloy: Microstructural Evolution and Properties‟ describes the microstructural evolution and microstructure-property correlation of this new alloy. Characterization analysis (X-ray diffraction, electron probe microanalysis and transmission electron microscopy) confirms that the microstructure of this alloy contains similar kind of nanometer sized L12 ordered particles with lower number density as compared to Cu95Fe2.5Si2.5 alloy (Relative planar number density of the particles: Cu98Fe1.0Si1.0 = 0.13 and Cu95Fe2.5Si2.5 = 0.20). This nano sized coherently ordered particles show the similar Ashby-Brown strain contrast and are rich in iron and silicon similar to the Cu95Fe2.5Si2.5 alloy. This dilute alloy exhibits slight improvement in transport properties in comparison to the earlier Cu95Fe2.5Si2.5 alloy. The electrical resistivity of this alloy at 250C is 3.438E-6 Ohm-cm (Cu95Fe2.5Si2.5 = 3.5053 × 10-6 Ohm-cm at 250C). The thermal conductivity values of this alloy are 243 W/m.K and 338 W/m.K at 500C and 6000C respectively (Cu95Fe2.5Si2.5 = 236 W/m.K at 500C and 313 W/m.K at 6000C). This increase in transport properties is associated with further compositional dilution and the presence of lower number density of the ordered particles in the copper matrix. The mechanism of strengthening is similar to the earlier alloys. The only difference lies in the fact that this present alloy contains lower number density of the L12 ordered particles in the copper matrix. This lower number density is responsible for the loss in mechanical strength of this alloy. The room temperature yield strength and the ultimate tensile strength of this present alloy are 467±16 MPa and 558±12 MPa whereas yield strength and ultimate tensile strength at 6000C are recorded as 102±13 MPa and 110±12 MPa respectively. Though the alloy exhibits some loss in mechanical strength, the values are still attractive in comparison to other commercially available copper based alloys. Both the alloy Cu98Fe1.0Si1.0 and Cu95Fe2.5Si2.5 demonstrate an excellent balance of mechanical strength and transport properties and have the potential to become a high strength and high conductivity materials for high temperature applications. Chapter seven is entitled as „Comparison between the alloy systems‟. In this chapter, we have presented a comparison of our new alloys with other commercially available Cu-base alloys. The thesis ends with a chapter titled as “Suggestions for future work”. We have included a descriptive note for possible future extension of our current work in this chapter.

[pt] A aplicação do Concreto de Alta Resistência como material de construção está se tornando mais comum em estruturas de concreto. Esta tendência demanda um melhor conhecimento do material, incluindo os parâmetros que se referem à tensão limite na compressão. Sendo um material relativamente novo, com um conhecido comportamento frágil, poucas informações a respeito de seu desempenho estão disponíveis para possibilitar o projeto correto de estruturas especiais. Como o material fornece uma resistência compressiva mais alta, os vãos das peças estruturais de concreto armado podem ser maiores, permitindo, por exemplo, a redução do número de pilares em edifícios. Neste caso, o efeito de escala da mecânica da fratura deve ser considerado no projeto estrutural, e a energia de fraturamento torna-se uma propriedade fundamental no controle de resistências à flexão e corte das peças estruturais de concreto armado. Nesta dissertação, alguns resultados obtidos através de ensaios para determinação da energia de fraturamento são apresentados. Os testes à flexão de vigas com entalhe foram realizados na PUC - Rio para diferentes traços de concreto, com resistência compressiva igual ou superior a 40 MPa. Os testes foram feitos segundo especificações fornecidas na RILEM 50-FMC e foram executados em sistemas de teste de materiais com controle de deslocamentos. Os traços do concreto foram estabelecidos com o objetivo de utilizar concretos comumente usados pelas empresas que atuam no Brasil. / [en] The application of high-performance concrete as a construction material is becoming increasingly common in conventional concrete structures. This trend demands a better knowledge of the material, besides the parameter that refers to the limit stress in compression. Being a relatively new material, with a known brittle behavior, few information about its performance is available for design engineers that allows the correct design of special structures. As the material provides a higher compressive strength, concrete structural members can increase in size, allowing the reduction of the number of columns in a building, for example. In this case, the fracture mechanics size effect should be considered in the structural design, and the fracture energy turns to be a fundamental property in controlling the flexural and shear strength of the concrete structural members. In this dissertation, some results obtained through experimental tests for determination of fracture energy for high-performance concrete are presented. The three-point bend tests were conducted at PUC-Rio for different compositions of concrete, with compressive strength equals to or greater than 40 MPa. The tests comply with the specifications given in RILEM recommendations, RILEM 50-FMC and were performed in a servo-controlled materials testing system. The compositions of the concrete were established in order to match the concrete commonly used by the companies that operate in Brazil. / [es] La aplicación del Concreto de Alta Resistencia como material de construción está se tornando más común en extructuras de concreto. Esta tendencia demanda un mejor conocimiento del material, incluyendo los parámetros que se refieren a la tensión límite en la compresión. Siendo un material relativamente nuevo, con un conocido comportamiento frágil, son pocas las informaciones disponibles a respecto de su desempeño. Como el material ofrece una resistencia compresiva más alta, los vans de las piezas extructurales de concreto armado pueden ser mayores, permitiendo, por ejemplo, la reducción del número de pilares en edificios. En este caso, el efecto de escala de la mecánica de fracturas debe ser considerado en el proyecto extructural, y la energía de fractura se torna una propriedad fundamental en el control de resistencias a la flexión y corte de piezas extructurales de concreto armado. En esta disertación, se presentan algunos resultados obtenidos a través de ensayos para determinación de la energía de fractura. Las pruebas a la flexión de vigas fueron realizados en la PUC - Rio para diferentes trazos de concreto, con resistencia compresiva igual o superior la 40 MPa. Las pruebas fueron realizadas según especificaciones ofrecidas en la RILEM 50-FMC y se ejecutaron en sistemas de test de materiales con control de deslocamientos. Fueron establecidos los trazos de concreto con el objetivo de utilizar concretos comumente utilizados por las empresas que actúan en Brasil.

In recent years a strong interest has been expressed to produce lighter structures.One possible solution to reduce the weight is to utilize high strength steels and use welding as the joining method. Many components experience fatigue loadingduring all or part of their life time and welded connections are often the prime location of fatigue failure. This becomes more critical in welded high strength steels as fatigue strength of welds does not increase by increasing the steel strength. A possible solution to overcome this issue is to use fatigue improvement methods.The main objectives of this project are, therefore, to increase understanding of the factors that control fatigue life and to investigate how the fatigue strength improvement methods; high frequency mechanical impact (HFMI) treatment and use of Low Transformation Temperature (LTT) consumables will affect fatigue properties of welds in high strength steels. In this regard, Gas Metal Arc Welding(GMAW) was used to produce butt and fillet welds using LTT or conventional fillers in steels with yield strengths ranging from 650-1021 MPa and T-joint weldsin a steel with 1300 MPa yield strength. The effect of HFMI on fatigue strength of the welds in 1300 MPa yield strength steels was also investigated. Butt and fillet welds in 650-1021 MPa steels were fatigue tested under constant amplitude tensile loading with a stress ratio of 0.1 while T-joints were fatigue tested under constant amplitude fully reversed bending load with a stress ratio of -1. The nominal stress approach was used for fatigue strength evaluation of butt and fillet welds whereas the effective notch stress approach was used in case of T-joints. Relative effectsof the main parameters such as residual stress and weld toe geometry influencing fatigue strength of welds were evaluated. Residual stresses were measured using X-ray diffraction for as-welded and HFMI treated welds. Neutron diffraction was additionally used to investigate the near surface residual stress distribution in 1300 MPa LTT welds.Results showed that use of LTT consumables increased fatigue strength of welds in steels with yield strengths ranging from 650-1021 MPa. For butt welds, the vii characteristic fatigue strength (FAT) of LTT welds at 2 million cycles was up to46% higher when compared to corresponding welds made with conventional fillermaterials. In fillet welds, a maximum improvement of 132% was achieved when using LTT wires. The increase in fatigue strength was attributed to the lower tensile residual stresses or even compressive stresses produced close to the weldtoe in LTT welds. Weld metals with martensite transformation start temperatures around 200 °C produced the highest fatigue strength. In 1300 MPa yield strength steel, similar FAT of 287 MPa was observed for LTT welds and 306 MPa for conventional welds, both much higher than the IIW FATvalue of 225 MPa. The relative transformation temperatures of the base and weldmetals, specimen geometry and loading type are possible reasons why the fatigue strength was not improved by use of LTT wires. Neutron diffraction showed that the LTT consumable was capable of inducing near surface compressive residual stresses in all directions at the weld toe. It was additionally found that there arevery steep stress gradients both transverse to the weld toe line and in the depth direction, at the weld toe. Due to difficulties to accurately measure residual stresses locally at the weld toe most often in the literature and recommendations residual stresses a few millimetre away from the weld toe are related to fatigue properties. However, this research shows that caution must be used when relating these to fatigue strength, in particular for LTT welds, as stress in the base materiala few millimetre from the weld toe can be very different from the stress locally at the weld toe.HFMI increased the mean fatigue strength of conventional welds in 1300 MPa steels about 26% and of LTT welds by 13%. It increased the weld toe radius slightly but produced a more uniform geometry along the treated weld toes. Large compressive residual stresses, especially in the longitudinal direction, were introduced adjacent to the weld toe for both LTT and conventional treated welds. It was concluded that the increase in fatigue strength by HFMI treatment is due to the combined effect of weld toe geometry modification, increase in surface hardness and introduction of compressive residual stresses in the treated region.It was concluded that the residual stress has a relatively larger influence than the weld toe geometry on fatigue strength of welds. This is based on the observation that a moderate decrease in residual stress of about 15% at the 300 MPa stress level had the same effect on fatigue strength as increasing the weld toe radius by approximately 85% from 1.4 mm to 2.6 mm, in fillet welds. Also, a higher fatigue strength was observed for HFMI treated conventional welds compared to as welded samples having similar weld toe radii but with different residual stresses.

At an average age of 42 years, 10% of the nation’s over 607,000 bridges are posted for load restrictions, with an additional 15% considered structurally deficient or functionally obsolete. While there are major concerns with decks in 75% of structurally deficient bridges, often weight and geometry of the deck further limit the load rating and functionality of the bridge. Traditional deck systems and construction methods usually lead to prolonged periods of traffic delays, limiting options for transportation agencies to replace or widen a bridge, especially in urban areas. The purpose of this study was to develop a new generation of ultra-lightweight super shallow solid deck systems to replace open grid steel decks on movable bridges and as well serve as a viable alternative in bridge deck replacements across the country. The study has led to a lightweight low-profile asymmetric waffle deck made with advanced materials. The asymmetry comes from the arrangement of primary and secondary ribs, respectively perpendicular and parallel to the direction of traffic. The waffle deck is made with ultrahigh performance concrete (UHPC) reinforced with either high-strength steel (HSS) or carbon fiber reinforced polymer (CFRP) reinforcement. With this combination, the deck weight was limited to below 21 psf and its overall depth to only 4 inch, while still meeting the strength and ductility demands for 4 ft. typical stringer spacing. It was further envisioned that the ultra-high strength of UHPC is best matched with the high strength of HSS or CFRP reinforcement for an efficient system and the ductile behavior of UHPC can help mask the linear elastic response of CFRP reinforcement and result in an overall ductile system. The issues of consideration from the design and constructability perspectives have included strength and stiffness, bond and development length for the reinforcement, punching shear and panel action. A series of experiments were conducted to help address these issues. Additionally full-size panels were made for testing under heavy vehicle simulator (HVS) at the accelerated pavement testing (APT) facility in Gainesville. Detailed finite element analyses were also carried out to help guide the design of this new generation of bridge decks. The research has confirmed the superior performance of the new deck system and its feasibility.

Performance of buildings and bridges during past earthquakes has indicated that many of these structures are vulnerable to seismic damage and structural collapse. The deficiencies in pre-1970s design codes have resulted in poor performance of reinforced concrete structures during seismic excitations. The Richter Magnitude 6.6 - 1971 San Fernando Earthquake raised awareness for seismic retrofit needs of existing buildings for the first time. The majority of deficiencies of vulnerable concrete columns can be overcome through seismic retrofits that involve additional transverse reinforcement. This can be done either by providing reinforced concrete, steel, or fibre-reinforced polymer (FRP) jackets around existing columns; or by applying transverse prestressing to columns (RetroBelt System). The research project presented in this thesis involves a seismic retrofit methodology for seismically deficient building and bridge columns, utilizing the use of high-strength packaging straps as external reinforcement for transverse prestressing. The emphasis in the project is placed on experimental research. Three seismically deficient full-size reinforced concrete columns, with a circular, a square and a rectangular cross- section, either critical in shear or flexure, were designed, built and tested under simulated seismic loading. The results indicate that external prestressing of columns in transverse direction with high-strength steel straps improves ductility and energy dissipation capacity of seismically deficient columns. They further indicate that current analytical techniques can be used to predict the force-displacement relationships of columns. A design approach is presented for the retrofit methodology investigated.

No description available.

This master thesis deals with the development of an expansive anchor material. This material is intended especially for the engineering and power industry where the operating conditions cause thermal stresses of the anchor. In order to meet the requirements for a firm and secure connection of the anchored part, it is necessary to achieve excellent physical-mechanical properties of the developed material such as high compressive strength, high tensile strength based on the base, and resistance to thermal stresses till 200 ° C. All of these processes must be achieved after the ageing of the cement material. Due to the current trend of modern materials that are environmentally friendly, the use of partial replacements for Portland cement is used as a substitute for a primary binder.

The subject of the diploma thesis is the preparation of macro-defect-free (MDF) composites based on calcium-aluminate cement and organic polymer polyvinylalcohol. Attention focused on the optimization of the dose, the degree of hydrolysis and molecular weight of the polymer with respect to the heat resistance of the material. Thermal degradation of polyvinyl alcohol leads to changes in the structure of MDF composite. The study was mainly focused on the characteristics of polyvinyl alcohol dosage associated with the resultant mechanical properties of the material. During the work were monitored for changes in the mechanical properties of samples were cured at 60 °C and subsequently fired at 180 °C, 600 °C, 1000 °C and 1400 °C. It was tested in flexural strength, heat microscopy, TGA-DTA-EGA and SEM analysis.

Properties of weld at the high-powered welding methods. Description of MIG/MAG welding, LaserHybrid, Time Twin Digital. Steel Characteristic IMEX 700/DILLIMAX 690. Evaluation of weld with methods Time Twin Digital. Results of drawing, bending examinations, examination of hardness test and structure of weld surface.

In the last decades, significant improvements regarding the design, materials and technology of rock drills have been made. Likewise, in sheet metal forming, forming tools experience very high contact pressures when processing high strength steel sheets. In both applications components operate under extremely tough contact conditions that result in an accelerated component failure. Enhancements on mechanical properties of components material subjected to extreme contact conditions are highly required in order to withstand the application loads and prevent severe wear. The present thesis was focused on understanding of machinery component damage mechanisms under severe contact conditions. A case study of worn components used in rock drilling and sheet metal cold work was carried out. Thread joints from rock drilling and punches from sheet metal pressing were selected for the investigation. For these components, sliding contact under high contact pressure is a common load condition under the components usage. Then, to understand and quantify the influence of contact parameters, load and surface quality on material performance, laboratory simulations were performed. The results were used for a comparative analysis of the typical damage mechanisms observed in the tests and the case study of the components. The case study results showed that the threaded surfaces underwent severe plastic deformation due to the high-pressure sliding contact. The microstructure beneath the worn surface was altered and surface cracks and delamination were frequently observed at the worn surface. The dominant damage mechanism found on the investigated punches was adhesive wear. Material transfer adds friction stresses at the punch surface and ultimately, with repeated punch strokes, it leads to initiation and propagation of fatigue cracks. Wear process in thread joint and punch wear was simulated using the SOFS. The worn specimens tested experimentally showed similar wear mechanisms obtained in the case study. The thread joint wear simulation showed that the total damage at the worn surface was a result of adhesive wear, plastic deformation, and initiation and propagation of fatigue cracks. In addition, the results showed that the type of motion had a significant influence on the worn volume and crack initiation, and more severe wear was observed at reciprocal motion. The punch wear simulation showed that the friction quickly increased as work material from metal sheets transferred to the disc surface. The rate of the material transfer was strongly dependent on the combination of sheet material and tool steel. Further, the present experimental simulations were applicable to characterize and predict wear of components in the application. / Components used in rock drilling and sheet metal forming operate under harsh contact conditions that result in an early-life component failure. Wear and fatigue are considered as the most common damage mechanism for these components. Commonly, the service life of a component is designed based on its fatigue life. However, wear might have a significant effect on the components life too. Wear results in a surface damage that in turn may cause a fatigue crack initiation. Therefore, knowledge about wear of materials and components is a key factor in design and prediction of the lifetime of the components. In order to predict wear of a certain component, a thorough understanding of the component with regards to its material properties, application loads and working environment, and damage mechanisms is required. The overall aim of the present work was to define the typical wear mechanisms occurred on machinery components used in rock drilling and sheet metal forming. A comparative analysis of the case studies and results from performed laboratory tests simulated wear mechanisms in the applications highlighted wear mechanisms and factors influencing severity of wear in the applications. Obtained information is crucial for ranking and selection of the best material in the applications. / <p>The presentation will will be via zoom. PhD student will together with the supervisors will be in Karlstad while the opponent is in Luleå. </p>