cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14321604
title: Determination of elastic properties of polymeric pieces constructed by 3D printing, subjected to bending

description: ABSTRACT The method of Fused Deposition Modelling (MDF) for polymers processing - usually called 3D printing - is one of the additive construction technologies with greatest impact in recent years. The irruption of low cost machines and the continuous improvement in quality and resistance of employed polymers, demand to estimate the life time and performance of printed parts. Hence, this work analyses the mechanical performance under bending efforts of polymers, typically used in additive construction. In particular, the bending elastic modulus is evaluated - through experiments designed "ad-hoc" - in Poly Lactic Acid (PLA), Nylon, and High Impact Polystyrene (HIPS) probes, as a function of tracing direction, orientation of printed parts, presence of dye additives in polymers, and printing speed. We found that all the studied variability factors significantly modify the bending elastic modulus. Analysis of filaments orientation in the three materials reveals that the MDF technique produces anisotropic pieces. The highest elastic modulus is achieved when all filament directions match the direction of main stresses. Besides, the dye additives have significant influence as well as the orientation of the printed parts. Besides, we verified that the elastic modulus decreases with increasing printing speed.
DOI: 10.6084/m9.figshare.14321604.v1
title: Determination of elastic properties of polymeric pieces constructed by 3D printing, subjected to bending

description: ABSTRACT The method of Fused Deposition Modelling (MDF) for polymers processing - usually called 3D printing - is one of the additive construction technologies with greatest impact in recent years. The irruption of low cost machines and the continuous improvement in quality and resistance of employed polymers, demand to estimate the life time and performance of printed parts. Hence, this work analyses the mechanical performance under bending efforts of polymers, typically used in additive construction. In particular, the bending elastic modulus is evaluated - through experiments designed "ad-hoc" - in Poly Lactic Acid (PLA), Nylon, and High Impact Polystyrene (HIPS) probes, as a function of tracing direction, orientation of printed parts, presence of dye additives in polymers, and printing speed. We found that all the studied variability factors significantly modify the bending elastic modulus. Analysis of filaments orientation in the three materials reveals that the MDF technique produces anisotropic pieces. The highest elastic modulus is achieved when all filament directions match the direction of main stresses. Besides, the dye additives have significant influence as well as the orientation of the printed parts. Besides, we verified that the elastic modulus decreases with increasing printing speed.
DOI: 10.6084/m9.figshare.14321607.v1
title: Deposition of carbonaceous films in AISI D6 steel using the cathodic cage technique

description: ABSTRACT In this work, thin films of diamond-like carbon DLC (Diamond-like carbon) were deposited on substrates of AISI D6 tool steel by means of the plasma deposition technique with cathodic cage of graphite, with the objective of evaluating the influence of the treatment parameters, such as the duration of the treatment and the polarization of the samples. The treated samples were evaluated in terms of morphology and structure by X-ray Diffraction (XRD), Raman Spectroscopy and Scanning Electron Microscopy (SEM). The results of the diffractograms indicated the presence of the ferrite, graphite and diamond structures for the samples treated with alumina and the formation of graphite with hexagonal structure for treated samples without alumina. The Raman spectra identified the D and G bands characteristic of graphite materials and the best results were obtained for samples that did not use alumina. Micrographs of the films using alumina indicated structures in the form of tiny particles, with clearer and defined contours. As for the non-alumina samples, the DLC films presented a more uniform appearance and coalescence of the grains. The layers of the alumina treated samples had the highest layer thicknesses, especially for the treated sample for 6 hours. Regarding the treatments without alumina, the samples treated for 5 and 6 hours presented on average the highest layer thickness. Thus, it was possible to affirm that the alumina and, also, the time of treatment influence in a significant way the characteristics of microstructure and final thickness of the film.
DOI: 10.6084/m9.figshare.14321607
title: Deposition of carbonaceous films in AISI D6 steel using the cathodic cage technique

description: ABSTRACT In this work, thin films of diamond-like carbon DLC (Diamond-like carbon) were deposited on substrates of AISI D6 tool steel by means of the plasma deposition technique with cathodic cage of graphite, with the objective of evaluating the influence of the treatment parameters, such as the duration of the treatment and the polarization of the samples. The treated samples were evaluated in terms of morphology and structure by X-ray Diffraction (XRD), Raman Spectroscopy and Scanning Electron Microscopy (SEM). The results of the diffractograms indicated the presence of the ferrite, graphite and diamond structures for the samples treated with alumina and the formation of graphite with hexagonal structure for treated samples without alumina. The Raman spectra identified the D and G bands characteristic of graphite materials and the best results were obtained for samples that did not use alumina. Micrographs of the films using alumina indicated structures in the form of tiny particles, with clearer and defined contours. As for the non-alumina samples, the DLC films presented a more uniform appearance and coalescence of the grains. The layers of the alumina treated samples had the highest layer thicknesses, especially for the treated sample for 6 hours. Regarding the treatments without alumina, the samples treated for 5 and 6 hours presented on average the highest layer thickness. Thus, it was possible to affirm that the alumina and, also, the time of treatment influence in a significant way the characteristics of microstructure and final thickness of the film.
DOI: 10.6084/m9.figshare.14321608
title: Corrosion failures of austenitic and duplex stainless steels in a biodiesel plant

description: ABSTRACT The neutralization of catalysts with hydrochloric acid is an important step in a biodiesel process which generates steel corrosion due to the decrease in pH, and the addition of chlorides in the medium. Other factor responsible for corrosion and consequently failures is the poor miscibility between biodiesel and acid water generating a heterogeneous coverage of the surface of the pipelines and equipment by biodiesel and acid water, presence of galvanic cells and localized corrosion. In this paper, corrosion failures of AISI 316L and 904L austenitic stainless steels (SS), and of SAF 2205, 2507 duplex SS in a biodiesel plant were identified and studied. The low pH, presence of chlorides, high thermal input in welding, temperature gradient and mainly proximity to the acid injection site play the major roles in corrosion which generate the studied failures. Corrosion failures occurred in pipes transporting biodiesel and acid water, in a spool of acid water injection, in a static biodiesel mixer with acidic water, in a cylindrical decanter vessel, and in heat exchangers.
DOI: 10.6084/m9.figshare.14321608.v1
title: Corrosion failures of austenitic and duplex stainless steels in a biodiesel plant

description: ABSTRACT The neutralization of catalysts with hydrochloric acid is an important step in a biodiesel process which generates steel corrosion due to the decrease in pH, and the addition of chlorides in the medium. Other factor responsible for corrosion and consequently failures is the poor miscibility between biodiesel and acid water generating a heterogeneous coverage of the surface of the pipelines and equipment by biodiesel and acid water, presence of galvanic cells and localized corrosion. In this paper, corrosion failures of AISI 316L and 904L austenitic stainless steels (SS), and of SAF 2205, 2507 duplex SS in a biodiesel plant were identified and studied. The low pH, presence of chlorides, high thermal input in welding, temperature gradient and mainly proximity to the acid injection site play the major roles in corrosion which generate the studied failures. Corrosion failures occurred in pipes transporting biodiesel and acid water, in a spool of acid water injection, in a static biodiesel mixer with acidic water, in a cylindrical decanter vessel, and in heat exchangers.
DOI: 10.6084/m9.figshare.14321610.v1
title: A simple empirical model to quantify the residual strain of a Cu-Al-Be-Nb shape memory alloy

description: ABSTRACT The wide knowledge of the thermomechanical behavior of shape memory alloys (SMAs) is necessary to obtain alloys with high thermal hysteresis, which makes it possible to eliminate the need for cryogenic means in many applications. In this way, the mathematical models appear as an effective alternative to describe this thermomechanical behavior. In the present work, a mathematical model was developed able to measure the residual strain for a Cu-Al-Be-Nb alloy as a function of the variables: strain, temperature and strain rate. It is observed that the results obtained through the model are presented with good agreement when compared with the experimental data. Furthermore, it was found that the model is capable of predicting the conditions necessary to obtain the maximum residual strain.
DOI: 10.6084/m9.figshare.14321610
title: A simple empirical model to quantify the residual strain of a Cu-Al-Be-Nb shape memory alloy

description: ABSTRACT The wide knowledge of the thermomechanical behavior of shape memory alloys (SMAs) is necessary to obtain alloys with high thermal hysteresis, which makes it possible to eliminate the need for cryogenic means in many applications. In this way, the mathematical models appear as an effective alternative to describe this thermomechanical behavior. In the present work, a mathematical model was developed able to measure the residual strain for a Cu-Al-Be-Nb alloy as a function of the variables: strain, temperature and strain rate. It is observed that the results obtained through the model are presented with good agreement when compared with the experimental data. Furthermore, it was found that the model is capable of predicting the conditions necessary to obtain the maximum residual strain.
DOI: 10.6084/m9.figshare.14321620
title: Pitting Corrosion Behavior of UNS S31803 and UNS S32304 Duplex Stainless Steels in 3.5 wt% NaCl Solution

description: ABSTRACT This work examined the pitting corrosion resistance of two types of duplex stainless steels: UNS S31803, with molybdenum, and UNS S32304, without molybdenum. Cyclic potentiodynamic polarization and critical pitting temperature (CPT) tests were performed in 3.5 wt% NaCl solution. Scanning electron microscopy (SEM) was used for analysis of the pits on the surface of samples. The two steels studied presented susceptible to pitting corrosion in 3.5 wt% NaCl solution. UNS S31803 steel showed a higher corrosion potential (Ecorr), pitting potential (Epit), and polarization resistance (Rp) compared to UNS S32304 steel. It was also observed that the UNS S31803 steel showed higher capacity to repassivation and CPT than the UNS S32304 steel.
DOI: 10.6084/m9.figshare.14321620.v1
title: Pitting Corrosion Behavior of UNS S31803 and UNS S32304 Duplex Stainless Steels in 3.5 wt% NaCl Solution

description: ABSTRACT This work examined the pitting corrosion resistance of two types of duplex stainless steels: UNS S31803, with molybdenum, and UNS S32304, without molybdenum. Cyclic potentiodynamic polarization and critical pitting temperature (CPT) tests were performed in 3.5 wt% NaCl solution. Scanning electron microscopy (SEM) was used for analysis of the pits on the surface of samples. The two steels studied presented susceptible to pitting corrosion in 3.5 wt% NaCl solution. UNS S31803 steel showed a higher corrosion potential (Ecorr), pitting potential (Epit), and polarization resistance (Rp) compared to UNS S32304 steel. It was also observed that the UNS S31803 steel showed higher capacity to repassivation and CPT than the UNS S32304 steel.
DOI: 10.6084/m9.figshare.14321622.v1
title: Effect of niobium addition on the properties and microstructure of a high chromium cast iron alloy

description: ABSTRACT High chromium cast iron (HCCI) is usually employed in equipment that experience high abrasive wear and therefore requires high resistance. Niobium could be added to these alloys to improve their resistance to wear. This study consisted in addressing the influence of 0.5% and 1.0% of niobium on the microstructure of a 26% Cr and 2.8% C HCCI alloy. Standard samples – without niobium – and samples with 0.5% and 1.0% Nb were melted, cut and then machined into adequate dimensions for tests. Two groups of samples – with and without heat treatment – were analyzed through X-ray Diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), Vickers and Rockwell-C hardness. Carbides Volume Fraction (CVF) was quantified in the heat-treated samples. The majority of NbC carbides were observed to be thin and presented a hook shaped morphology. In addition, it was noted a precipitation of Nb-rich layers around the M7C3 carbides, which could act as a higher hardness coating. There was significant reduction in carbide volume fraction, from an initial 33.3% to 28.1% for the 0.5 % Nb alloy, and further reduction to 24.9% for the 1.0% Nb alloy, it was also noted an alteration on the quasi-eutectic microstructure to a hypoeutectic microstructure. The NbC carbides prevented hardness reduction as a result of lowering the CVF in heat-treated alloys; however, the alloys without heat treatment experienced reductions in hardness.
DOI: 10.6084/m9.figshare.14321622
title: Effect of niobium addition on the properties and microstructure of a high chromium cast iron alloy

description: ABSTRACT High chromium cast iron (HCCI) is usually employed in equipment that experience high abrasive wear and therefore requires high resistance. Niobium could be added to these alloys to improve their resistance to wear. This study consisted in addressing the influence of 0.5% and 1.0% of niobium on the microstructure of a 26% Cr and 2.8% C HCCI alloy. Standard samples – without niobium – and samples with 0.5% and 1.0% Nb were melted, cut and then machined into adequate dimensions for tests. Two groups of samples – with and without heat treatment – were analyzed through X-ray Diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), Vickers and Rockwell-C hardness. Carbides Volume Fraction (CVF) was quantified in the heat-treated samples. The majority of NbC carbides were observed to be thin and presented a hook shaped morphology. In addition, it was noted a precipitation of Nb-rich layers around the M7C3 carbides, which could act as a higher hardness coating. There was significant reduction in carbide volume fraction, from an initial 33.3% to 28.1% for the 0.5 % Nb alloy, and further reduction to 24.9% for the 1.0% Nb alloy, it was also noted an alteration on the quasi-eutectic microstructure to a hypoeutectic microstructure. The NbC carbides prevented hardness reduction as a result of lowering the CVF in heat-treated alloys; however, the alloys without heat treatment experienced reductions in hardness.
DOI: 10.6084/m9.figshare.14321625
title: Investigating the use of wastes from the processing of eucalyptus wood for the compacted solid fuels production

description: ABSTRACT This study aimed to analyze the charcoals of bark, shavings and sawdust of Eucalyptus pellita, and the briquettes produced from these materials, carbonized at two temperatures. The bark, shavings and sawdust generated by mechanical processing were charred at temperatures of 400 °C and 600 °C. The physicochemical properties of the charcoals produced were compared with those of the carbonized wood at the same temperatures. Then the charred residues were briquetted and analyzed through equilibrium moisture, apparent specific mass, natural and forced degradation rate. Carbonization of the bark of Eucalyptus pellita wood increased the gravimetric yields in charcoal. There was a positive relationship between the carbonization temperature and the equilibrium moisture of the briquettes produced with the carbonized residues. The briquettes produced with charcoal from the carbonized bark at 400 ºC presented a high rate of thermal degradation.
DOI: 10.6084/m9.figshare.14321625.v1
title: Investigating the use of wastes from the processing of eucalyptus wood for the compacted solid fuels production

description: ABSTRACT This study aimed to analyze the charcoals of bark, shavings and sawdust of Eucalyptus pellita, and the briquettes produced from these materials, carbonized at two temperatures. The bark, shavings and sawdust generated by mechanical processing were charred at temperatures of 400 °C and 600 °C. The physicochemical properties of the charcoals produced were compared with those of the carbonized wood at the same temperatures. Then the charred residues were briquetted and analyzed through equilibrium moisture, apparent specific mass, natural and forced degradation rate. Carbonization of the bark of Eucalyptus pellita wood increased the gravimetric yields in charcoal. There was a positive relationship between the carbonization temperature and the equilibrium moisture of the briquettes produced with the carbonized residues. The briquettes produced with charcoal from the carbonized bark at 400 ºC presented a high rate of thermal degradation.
DOI: 10.6084/m9.figshare.14321626
title: Influence of corrosion and alternating cyclic stresses on fatigue life of FE 50010 and FE 50007 nodular cast irons

description: ABSTRACT The FE 50007 nodular cast iron is widely used in engineering applications, mainly in the automobile industry. However, in the last years the FE 50007 nodular cast iron is being replaced by the FE 50010 nodular cast iron because of its greater ductility. The ductility leads to a decrease in hardness, favoring the machining and, consequently, having a lower final cost of production. Besides the hardness, tensile mechanical properties also present a small difference between the materials. However, for engineering applications with dynamic loading the selection of the material also depends on its behavior in fatigue. Therefore, the aim of this work was to study the fatigue life of these two nodular cast irons under natural environmental conditions and after salt spray exposition. Before the fatigue tests the materials were characterized by chemical analysis, metallography, hardness and tensile tests. The fatigue tests were performed by rotating bending under natural environmental conditions and after salt spray corrosion for 48, 96, 168 and 240 hours. The FE 50007 cast iron has higher hardness and mechanical strength but less ductility than the FE 50010. These properties are related to the present phases: the FE 50007 is composed of graphite nodules, ferrite and cementite, while the FE 50010 is composed of graphite nodules and ferrite. The FE 50010 cast iron presented higher fatigue life for tensile bending equal or less than 250 MPa under natural environmental conditions. After exposure to salt spray, the FE 50010 cast iron also presented higher fatigue strength for a tensile bending of 250 MPa. The corrosion products are porous and brittle, and basically composed of iron oxides and hydroxides.
DOI: 10.6084/m9.figshare.14321626.v1
title: Influence of corrosion and alternating cyclic stresses on fatigue life of FE 50010 and FE 50007 nodular cast irons

description: ABSTRACT The FE 50007 nodular cast iron is widely used in engineering applications, mainly in the automobile industry. However, in the last years the FE 50007 nodular cast iron is being replaced by the FE 50010 nodular cast iron because of its greater ductility. The ductility leads to a decrease in hardness, favoring the machining and, consequently, having a lower final cost of production. Besides the hardness, tensile mechanical properties also present a small difference between the materials. However, for engineering applications with dynamic loading the selection of the material also depends on its behavior in fatigue. Therefore, the aim of this work was to study the fatigue life of these two nodular cast irons under natural environmental conditions and after salt spray exposition. Before the fatigue tests the materials were characterized by chemical analysis, metallography, hardness and tensile tests. The fatigue tests were performed by rotating bending under natural environmental conditions and after salt spray corrosion for 48, 96, 168 and 240 hours. The FE 50007 cast iron has higher hardness and mechanical strength but less ductility than the FE 50010. These properties are related to the present phases: the FE 50007 is composed of graphite nodules, ferrite and cementite, while the FE 50010 is composed of graphite nodules and ferrite. The FE 50010 cast iron presented higher fatigue life for tensile bending equal or less than 250 MPa under natural environmental conditions. After exposure to salt spray, the FE 50010 cast iron also presented higher fatigue strength for a tensile bending of 250 MPa. The corrosion products are porous and brittle, and basically composed of iron oxides and hydroxides.
DOI: 10.6084/m9.figshare.14321629
title: Effect of titanium content on the porosity and hardness of Cu-Ti-TiC composite sintered by abnormal glow discharge

description: ABSTRACT Copper metal matrix composites reinforced with TiC 1 % (%w/w) and titanium mass with fractions of 10 %, 15 % and 20 % were synthesized and characterized in order to evaluate the porosity in the material generated by the presence of titanium and material hardness. The MMC’s were manufactured by powder metallurgical route that included: mechanical and ultrasonic mixing of Cu-Ti-TiC in liquid suspension of 2-propanol, following by drying with subsequent uniaxial cold compaction at 400 MPa. Sintering by abnormal glow discharge at 850 °C in 10 % nitrogen and 90 % argon atmosphere; sintering time of 30 minutes and later cooling. Sintered samples were characterized by X-ray diffraction to determine the material phases. The morphological and compositional characterization were performed by scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS). Porosity in green and sintered conditions were estimated by digital image analysis. As a result, in the green samples were evidenced a porosity in the range between 5,2% and 7,21% with the three fractions of Ti. The sintered samples value close to 13,6% were obtained with concentrations of 20% of Ti. The X-ray diffraction analysis showed the majority presence of the Cu3Ti and CuTi2 phases at 850 °C. The results by SEM and EDS exhibited the distribution of titanium associated with diffusive phenomena during sintering process. The hardness data were determined with the use of Vickers microdurometer with a load of 100 gf, showing that the presence of higher titanium content had influenced the hardness due to the formation of intermetallic phases, increasing its values up to 454 HV.