In order to obtain ultrafine grained structure, commercially pure aluminium (Al 1050) plates were... more In order to obtain ultrafine grained structure, commercially pure aluminium (Al 1050) plates were subjected up to 8 passes of Incremental Equal Channel Angular Pressing (IECAP) following route C. Plates in different stages of IECAP were joined using Friction Stir Welding (FSW). All welded samples were investigated to determine their mechanical properties and structure evolution in the joint zone. The joining process reduced mechanical strength of material in the nugget zone, which was explained by the grain growth resulting from temperature rise during FSW. Nevertheless, the obtained results are promising in comparison to other methods of joining aluminium.
Highlights Ultrafine grained and coarse grained pure aluminium was investigated No changes in... more Highlights Ultrafine grained and coarse grained pure aluminium was investigated No changes in electrochemical response were observed between samples Pits nucleated at intermetallic particles The dissolution of material occurred along HAGBs The morphology of the pits reflects the array of the HAGBs
Archives of Civil and Mechanical Engineering, Nov 12, 2021
Copper rods with ultrafine-grained microstructure, obtained by multi-turn ECAP processing, were s... more Copper rods with ultrafine-grained microstructure, obtained by multi-turn ECAP processing, were subjected to Direct Drive Rotary Friction Welding using various processing parameters, such as rotational speed and pressure, which resulted in different energy and heat input. Even though friction welding is a high energy process, by a proper selection of processing parameters it was possible to maintain grain size at around 0.7 µm in the weld zone and preserve the UFG microstructure. These microstructural features translated into mechanical properties: the YS for those specimens was around 330 MPa. Processing parameters that resulted in a larger heat input caused an increase in grain size to around 2 µm; this, however, increased ductility and led to a uniform elongation exceeding 5%. Corrosion resistance in the stir zone increased, as was evident in the higher open circuit potential and higher corrosion potential in comparison with base material; the observed differences were about 50 mV. These changes can be explained by the higher fraction of HAGBs in the SZ.
Equal Channel Angular Pressing (ECAP) is one of the methods which allows to obtain ultrafinegrain... more Equal Channel Angular Pressing (ECAP) is one of the methods which allows to obtain ultrafinegrained and nanocrystalline metallic materials. It is well known that microstructure of materials processed by ECAP in not very stable. There were published many experimental and theoretical evidences of this fact obtained by various methods such as microstructure observations, properties measurement and computer modeling. The aim of presented paper was to investigate the thermal stability of microstructure and mechanical properties of the Al 5483 alloy processed by ECAP. As a result of performed investigations it was concluded that accumulated plastic deformation has no influence on the thermal stability of Al 5483 alloy processed by ECAP. It was also found that properly chosen parameters of ECAP and subsequent annealing allows to produce materials with high strength and plasticity.
Vacuum carburising with pre-nitriding (PreNitLPC ® technology) involves feeding ammonia during th... more Vacuum carburising with pre-nitriding (PreNitLPC ® technology) involves feeding ammonia during the charge heating stage before carburising. The purpose is to restrict the growth of grain in the surface layer of the carburised steel. The article presents the influence of nitrogen on restricting austenite grain growth during vacuum carburising and on mechanical properties (fatigue strength, impact resistance) of layers that underwent such treatment in comparison with traditional carburising methods.
The machining response of metallurgically and mechanically modified materials when they are proce... more The machining response of metallurgically and mechanically modified materials when they are processed by employing the micro wire EDM (μWEDM) technology is reported in this paper. In particular, the effects of the material microstructure on resulting surface integrity of Al5083 series aluminium alloys after μWEDM processing is investigated. The machining response of an "as received" aluminium alloy was compared against the results obtained on samples processed through extrusion strain hardening and severe plastic deformation. Especially, the process-material effects on the resulting phase content changes and surface hardness after both rough and finishing μWEDM cuts were analyzed. This study shows that an ultra-fine grain Al5083 material maintained its advantageous structural characteristics and superior mechanical properties after μWEDM. The machined surfaces of UFG material displayed a 30% higher micro hardness, when compared with 'as received' and 'conventio...
The properties of materials are directly related to their microstructure, one quantitative measur... more The properties of materials are directly related to their microstructure, one quantitative measure of which is the average grain size. Most of the strength properties of crystalline materials are improved with diminishing grain size, and therefore new technologies have been developed to produce also bulk metals with nanocrystalline or ultrafine grain sizes. In this paper, we report the results of compression experiments on ultrafine-grained 1070 aluminum produced by different routes of equal-channel angular pressing (ECAP). The compression tests were conducted at different strain rates and temperatures using a servo-hydraulic materials testing machine and the Split Hopkinson Pressure bar technique. The results show that both increasing strain rate and decreasing temperature increase the work hardening capability of ultrafine-grained aluminum, thus enhancing the ductility of the material. The strain rate dependence of ultrafine-grained aluminum is also higher than that of the coarse-...
Incremental ECAP, unlike conventional ECAP, works in small steps in which deformation and feeding... more Incremental ECAP, unlike conventional ECAP, works in small steps in which deformation and feeding are divided between two different tools acting asynchronously. Incremental processing reduces forces and allows processing in relatively large billets. The major advantage of this technique is that the specimens are in the form of plates with a rectangular shape, which makes them suitable for further processing, e.g. via deep drawing, which may extend the range of potential applications of UFG materials. Plates of 1xxx and 3xxx series aluminum were processed by Incremental ECAP and evaluated in terms of microstructure, mechanical properties, anisotropy and formability. It was demonstrated that incremental ECAP is one of the most effective severe plastic deformation methods in terms of grain size refinement and high angle grain boundaries formation. Eight passes brings about grain size reduction to below 500 nm and very high fraction of high angle grain boundaries of about 80%. The plate...
Tool steels are a widely used material for construction of tools designated for shaping and formi... more Tool steels are a widely used material for construction of tools designated for shaping and forming of metal, plastic and other elements in mass production. These elements include extruding dies, pressure casting dies, moulds, punches and various other elements for plastic shaping of other materials preheated to temperatures in the range of 250-700 °C (Fig. 1). Since shape stability constitutes the basic requirement any tool has to meet, the material it is made from is expected to withstand loads without any plastic strain while maintaining high abrasion resistance. Additionally, a tool should feature good hardness and strength as well as appropriate ductility and impact strength which condition crack resistance, and these qualities are to be obtained at high working temperatures (up to 700 °C).
Dynamic behavior of ultrafine-grained (UFG) commercially pure aluminum (AA1070) samples prepared ... more Dynamic behavior of ultrafine-grained (UFG) commercially pure aluminum (AA1070) samples prepared via two different equal-channel angular pressing (ECAP) routes was studied at high strain rates at room and sub-zero temperatures using the Hopkinson Split Bar technique, and at quasi-static strain rates at room temperature using a servohydraulic materials testing machine. For comparison, similar tests were also conducted on coarse-grained AA1070 aluminum samples. 3D- and 2D-ECAP dies were used to deform the initial coarse-grained aluminum to total equivalent plastic strains of ca. 10 using routes Bc and C+Bc, respectively. The ECAP processing increased the strength of the material substantially but at the same time reduced its strain hardening capability. After initial yielding, strain softening took place in all studied UFG materials at quasi- static strain rates, but at high strain rates (above 103 s-1) notable strain hardening was observed. Strain hardening was further enhanced by su...
S tale narzędziowe są szeroko stosowanym materiałem do kształtowania narzędzi z metali, polimerów... more S tale narzędziowe są szeroko stosowanym materiałem do kształtowania narzędzi z metali, polimerów, ceramik i kompozytów, przy czym nadawanie kształtu może odbywać się na drodze obróbki skrawaniem lub przeróbki plastycznej. Ponieważ zasadniczym wymaganiem stawianym narzędziu jest stałość kształtu, oczekuje się, że materiał z którego został wykonany, będzie znosił obciążenia bez odkształceń plastycznych oraz będzie wykazywał dużą odporność na ścieranie. Stale narzędziowe klasyfikuje się ze względu na zastosowania. Matryce, stemple, tłoczniki, rolki do prasowania i inne elementy do obróbki elementów nie nagrzanych wykonywane są ze stali stopowych do pracy na zimno, takich jak NCLV, NC10, NC11LV, NZ3 (jakkolwiek w praktyce zarówno materiał jak i narzędzia Stale narzędziowe stanowią podstawowy materiał do formowania wszystkich grup materiałów do produkcji narzędzi. Prawidłowo zaprojektowany i kontrolowany proces chłodzenia ma zasadnicze znaczenie dla efektu końcowego obróbki cieplnej elementu, a tym samym na jego trwałość i przydatność użytkową. Nowoczesne urządzenia i technologie obróbki cieplnej umożliwiają wielkoseryjną i skuteczną obróbkę cieplną stali narzędziowych, natomiast symulatory takie jak G-Quench Pro® umożliwiają tworzenie nowych metod obróbki przy równoczesnym zmniejszeniu czasochłonnych procesów testowych.
The goal of this study was to examine performance of various lubricants for aluminium alloy AA508... more The goal of this study was to examine performance of various lubricants for aluminium alloy AA5083. Conventional ring compression tests were conducted at 200 °C. Samples were compressed to 50% of the initial height with a constant ram velocity 0.5 mm/s using a servo-controlled hydraulic press. The optimization procedure was implemented in self-developed software to identify friction factors from experiments. The application launches remotely finite element (FE) simulations of ring compression with a changing friction factor until a difference between experiment and numerical prediction of the internal diameter of the sample is smaller than 0.5%. FE simulations were run using Forge3 commercial software. The obtained friction factor quantitatively describes performance of a lubricant and can be used as an input parameter in FE simulation of other processes. It was shown that application of calcium aluminate conversion coating as pre-lubrication surface treatment reduced friction facto...
In order to obtain ultrafine grained structure, commercially pure aluminium (Al 1050) plates were... more In order to obtain ultrafine grained structure, commercially pure aluminium (Al 1050) plates were subjected up to 8 passes of Incremental Equal Channel Angular Pressing (IECAP) following route C. Plates in different stages of IECAP were joined using Friction Stir Welding (FSW). All welded samples were investigated to determine their mechanical properties and structure evolution in the joint zone. The joining process reduced mechanical strength of material in the nugget zone, which was explained by the grain growth resulting from temperature rise during FSW. Nevertheless, the obtained results are promising in comparison to other methods of joining aluminium.
Highlights Ultrafine grained and coarse grained pure aluminium was investigated No changes in... more Highlights Ultrafine grained and coarse grained pure aluminium was investigated No changes in electrochemical response were observed between samples Pits nucleated at intermetallic particles The dissolution of material occurred along HAGBs The morphology of the pits reflects the array of the HAGBs
Archives of Civil and Mechanical Engineering, Nov 12, 2021
Copper rods with ultrafine-grained microstructure, obtained by multi-turn ECAP processing, were s... more Copper rods with ultrafine-grained microstructure, obtained by multi-turn ECAP processing, were subjected to Direct Drive Rotary Friction Welding using various processing parameters, such as rotational speed and pressure, which resulted in different energy and heat input. Even though friction welding is a high energy process, by a proper selection of processing parameters it was possible to maintain grain size at around 0.7 µm in the weld zone and preserve the UFG microstructure. These microstructural features translated into mechanical properties: the YS for those specimens was around 330 MPa. Processing parameters that resulted in a larger heat input caused an increase in grain size to around 2 µm; this, however, increased ductility and led to a uniform elongation exceeding 5%. Corrosion resistance in the stir zone increased, as was evident in the higher open circuit potential and higher corrosion potential in comparison with base material; the observed differences were about 50 mV. These changes can be explained by the higher fraction of HAGBs in the SZ.
Equal Channel Angular Pressing (ECAP) is one of the methods which allows to obtain ultrafinegrain... more Equal Channel Angular Pressing (ECAP) is one of the methods which allows to obtain ultrafinegrained and nanocrystalline metallic materials. It is well known that microstructure of materials processed by ECAP in not very stable. There were published many experimental and theoretical evidences of this fact obtained by various methods such as microstructure observations, properties measurement and computer modeling. The aim of presented paper was to investigate the thermal stability of microstructure and mechanical properties of the Al 5483 alloy processed by ECAP. As a result of performed investigations it was concluded that accumulated plastic deformation has no influence on the thermal stability of Al 5483 alloy processed by ECAP. It was also found that properly chosen parameters of ECAP and subsequent annealing allows to produce materials with high strength and plasticity.
Vacuum carburising with pre-nitriding (PreNitLPC ® technology) involves feeding ammonia during th... more Vacuum carburising with pre-nitriding (PreNitLPC ® technology) involves feeding ammonia during the charge heating stage before carburising. The purpose is to restrict the growth of grain in the surface layer of the carburised steel. The article presents the influence of nitrogen on restricting austenite grain growth during vacuum carburising and on mechanical properties (fatigue strength, impact resistance) of layers that underwent such treatment in comparison with traditional carburising methods.
The machining response of metallurgically and mechanically modified materials when they are proce... more The machining response of metallurgically and mechanically modified materials when they are processed by employing the micro wire EDM (μWEDM) technology is reported in this paper. In particular, the effects of the material microstructure on resulting surface integrity of Al5083 series aluminium alloys after μWEDM processing is investigated. The machining response of an "as received" aluminium alloy was compared against the results obtained on samples processed through extrusion strain hardening and severe plastic deformation. Especially, the process-material effects on the resulting phase content changes and surface hardness after both rough and finishing μWEDM cuts were analyzed. This study shows that an ultra-fine grain Al5083 material maintained its advantageous structural characteristics and superior mechanical properties after μWEDM. The machined surfaces of UFG material displayed a 30% higher micro hardness, when compared with 'as received' and 'conventio...
The properties of materials are directly related to their microstructure, one quantitative measur... more The properties of materials are directly related to their microstructure, one quantitative measure of which is the average grain size. Most of the strength properties of crystalline materials are improved with diminishing grain size, and therefore new technologies have been developed to produce also bulk metals with nanocrystalline or ultrafine grain sizes. In this paper, we report the results of compression experiments on ultrafine-grained 1070 aluminum produced by different routes of equal-channel angular pressing (ECAP). The compression tests were conducted at different strain rates and temperatures using a servo-hydraulic materials testing machine and the Split Hopkinson Pressure bar technique. The results show that both increasing strain rate and decreasing temperature increase the work hardening capability of ultrafine-grained aluminum, thus enhancing the ductility of the material. The strain rate dependence of ultrafine-grained aluminum is also higher than that of the coarse-...
Incremental ECAP, unlike conventional ECAP, works in small steps in which deformation and feeding... more Incremental ECAP, unlike conventional ECAP, works in small steps in which deformation and feeding are divided between two different tools acting asynchronously. Incremental processing reduces forces and allows processing in relatively large billets. The major advantage of this technique is that the specimens are in the form of plates with a rectangular shape, which makes them suitable for further processing, e.g. via deep drawing, which may extend the range of potential applications of UFG materials. Plates of 1xxx and 3xxx series aluminum were processed by Incremental ECAP and evaluated in terms of microstructure, mechanical properties, anisotropy and formability. It was demonstrated that incremental ECAP is one of the most effective severe plastic deformation methods in terms of grain size refinement and high angle grain boundaries formation. Eight passes brings about grain size reduction to below 500 nm and very high fraction of high angle grain boundaries of about 80%. The plate...
Tool steels are a widely used material for construction of tools designated for shaping and formi... more Tool steels are a widely used material for construction of tools designated for shaping and forming of metal, plastic and other elements in mass production. These elements include extruding dies, pressure casting dies, moulds, punches and various other elements for plastic shaping of other materials preheated to temperatures in the range of 250-700 °C (Fig. 1). Since shape stability constitutes the basic requirement any tool has to meet, the material it is made from is expected to withstand loads without any plastic strain while maintaining high abrasion resistance. Additionally, a tool should feature good hardness and strength as well as appropriate ductility and impact strength which condition crack resistance, and these qualities are to be obtained at high working temperatures (up to 700 °C).
Dynamic behavior of ultrafine-grained (UFG) commercially pure aluminum (AA1070) samples prepared ... more Dynamic behavior of ultrafine-grained (UFG) commercially pure aluminum (AA1070) samples prepared via two different equal-channel angular pressing (ECAP) routes was studied at high strain rates at room and sub-zero temperatures using the Hopkinson Split Bar technique, and at quasi-static strain rates at room temperature using a servohydraulic materials testing machine. For comparison, similar tests were also conducted on coarse-grained AA1070 aluminum samples. 3D- and 2D-ECAP dies were used to deform the initial coarse-grained aluminum to total equivalent plastic strains of ca. 10 using routes Bc and C+Bc, respectively. The ECAP processing increased the strength of the material substantially but at the same time reduced its strain hardening capability. After initial yielding, strain softening took place in all studied UFG materials at quasi- static strain rates, but at high strain rates (above 103 s-1) notable strain hardening was observed. Strain hardening was further enhanced by su...
S tale narzędziowe są szeroko stosowanym materiałem do kształtowania narzędzi z metali, polimerów... more S tale narzędziowe są szeroko stosowanym materiałem do kształtowania narzędzi z metali, polimerów, ceramik i kompozytów, przy czym nadawanie kształtu może odbywać się na drodze obróbki skrawaniem lub przeróbki plastycznej. Ponieważ zasadniczym wymaganiem stawianym narzędziu jest stałość kształtu, oczekuje się, że materiał z którego został wykonany, będzie znosił obciążenia bez odkształceń plastycznych oraz będzie wykazywał dużą odporność na ścieranie. Stale narzędziowe klasyfikuje się ze względu na zastosowania. Matryce, stemple, tłoczniki, rolki do prasowania i inne elementy do obróbki elementów nie nagrzanych wykonywane są ze stali stopowych do pracy na zimno, takich jak NCLV, NC10, NC11LV, NZ3 (jakkolwiek w praktyce zarówno materiał jak i narzędzia Stale narzędziowe stanowią podstawowy materiał do formowania wszystkich grup materiałów do produkcji narzędzi. Prawidłowo zaprojektowany i kontrolowany proces chłodzenia ma zasadnicze znaczenie dla efektu końcowego obróbki cieplnej elementu, a tym samym na jego trwałość i przydatność użytkową. Nowoczesne urządzenia i technologie obróbki cieplnej umożliwiają wielkoseryjną i skuteczną obróbkę cieplną stali narzędziowych, natomiast symulatory takie jak G-Quench Pro® umożliwiają tworzenie nowych metod obróbki przy równoczesnym zmniejszeniu czasochłonnych procesów testowych.
The goal of this study was to examine performance of various lubricants for aluminium alloy AA508... more The goal of this study was to examine performance of various lubricants for aluminium alloy AA5083. Conventional ring compression tests were conducted at 200 °C. Samples were compressed to 50% of the initial height with a constant ram velocity 0.5 mm/s using a servo-controlled hydraulic press. The optimization procedure was implemented in self-developed software to identify friction factors from experiments. The application launches remotely finite element (FE) simulations of ring compression with a changing friction factor until a difference between experiment and numerical prediction of the internal diameter of the sample is smaller than 0.5%. FE simulations were run using Forge3 commercial software. The obtained friction factor quantitatively describes performance of a lubricant and can be used as an input parameter in FE simulation of other processes. It was shown that application of calcium aluminate conversion coating as pre-lubrication surface treatment reduced friction facto...
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