Maria Teresa Aguilar - Academia.edu (original) (raw)
Papers by Maria Teresa Aguilar
A Construção Civil: em uma perspectivas econômica, ambiental e social
Quenching commonly causes a geometric distortion in the parts, associated with the thermal contra... more Quenching commonly causes a geometric distortion in the parts, associated with the thermal contraction and with the change in the mechanical and geometrical properties of austenite and martensite. It is of importance to predict the geometric behavior of mechanical components during heat treatment in order to improve the quality of the product, modifying the heat treatment process, or even defining a straightening process in order to correct the distortions. This study presents the finite element (FE) simulations of the quenching of AISI 4140 steel C-rings in oil and water. The severity of the water quenching was responsible for the larger distortion when compared to the oil water quenching process. The simulations are carried out with coupled analysis of heat transfer, deformation mechanics and phase transformations. In addition, hardness and phase transformation were conducted through numerical simulation.
ABM Proceedings, 2018
Resumo Os aços elétricos tem sido uma alternativa para aperfeiçoar a relação eficiência/perda mag... more Resumo Os aços elétricos tem sido uma alternativa para aperfeiçoar a relação eficiência/perda magnética dos equipamentos elétricos, sem a necessidade de grandes alterações de projeto Esses aços, também conhecidos como aços ao silício, podem ser de grão orientado ou não orientado, sendo suas propriedades, de modo geral, dependentes das diferentes condições adotadas para o processamento dos mesmos. Deste modo, considerando essa relação entre as condições de solicitação mecânica e o desempenho desses materiais este trabalho apresenta o estudo da resposta magnética exibida pelo aço de grão orientado após as chapas desse material serem submetidas à rota de processamento envolvendo a aplicação dos esforços de cisalhamento direto / cisalhamento reverso (cisalhamento cíclico). Os resultados indicaram a dependência das propriedades em função da quantidade de deformação plástica, ocasionando, de modo geral, o decaimento do desempenho magnético do mesmo. Palavras-chave: Aço GO; Ensaio Barkhausen; Cisalhamento cíclico, EFFECT OF CYCLIC SHEARING ON THE MAGNETIC PROPERTY OF GO STEEL
Materials Research, 2020
Severe plastic deformation (SPD) of metals leads to their strengthening and grain refinement, but... more Severe plastic deformation (SPD) of metals leads to their strengthening and grain refinement, but to low uniform elongations. Low Strain Amplitude Multi Directional Forging (LSA-MDF) is an important method for increasing this low uniform elongation. The application of workpieces of SPD-processed materials requires that their distributions of mechanical properties, microstructures and deformation be as homogeneous as possible. Analyses of these distributions after LSA-MDF have not been found in the literature, and are presented in the current investigation utilizing microhardness measurements, optical and electronic microscopy and finite element simulations. LSA-MDF causes higher strains, mcrohardeness and structural distortions in the central regions of the specimens than at their edges and corners. In addition, LSA-MDF utilizing confined compressions seems to be the preferred processing route, due to its ease and to the more homogeneous microhardness, microstructure and strain distributions in relation to other experimental procedures.
Matéria (Rio de Janeiro), 2020
RESUMO O vidro soda-cal-sílica é um material com alto potencial de reciclagem. No entanto, o seu ... more RESUMO O vidro soda-cal-sílica é um material com alto potencial de reciclagem. No entanto, o seu beneficiamento gera micropartículas que ficam suspensas na água utilizada para resfriamento das ferramentas. Esse resíduo é inerte e, comumente, não reaproveitado. Para seu descarte é feita a decantação das micropartículas de vidro utilizando floculantes, sendo a lama produzida depositada em aterros sanitários. De acordo com a literatura, essas micropartículas de vidro poderiam atuar como material cimentício suplementar na produção de cimento Portland. Contudo, as informações sobre o desempenho térmico desses materiais são escassas. Neste estudo investiga-se a difusividade térmica de argamassas para fins estruturais confeccionadas com cimento Portland e lama de vidro soda-cal-sílica com características pozolânicas. Foram produzidas argamassas com e sem substituição do cimento por 10 e 20% de lama in natura e lama lavada para retirada do floculante. As argamassas foram caracterizadas quan...
Matéria (Rio de Janeiro), 2020
RESUMO Um método alternativo para produção de concretos ecoeficientes seria a substituição parcia... more RESUMO Um método alternativo para produção de concretos ecoeficientes seria a substituição parcial de cimento Portland por resíduos de pastas e argamassas submetidas a um tratamento termomecânico. Neste contexto, este estudo avalia a influência da relação água/cimento (a/c) e do tamanho médio das partículas na decomposição térmica do cimento hidratado. Pastas de cimento com três relações a/c (0,40, 0,50 e 0,60) e curadas por 28 dias foram moídas para obtenção de granulometrias com tamanho médio de 0,60 mm e 0,15 mm. A decomposição térmica das pastas foi analisada por termogravimetria (TGA), difração de raios X (DRX) e espectroscopia no infravermelho por Transformada de Fourier (FTIR). A análise de TGA indica que o teor de água quimicamente combinada é favorecido pelo aumento da relação a/c entre 0,40 e 0,50, mas é constante para a/c de 0,50 e 0,60. A redução do tamanho médio quase não interfere nas curvas de TGA. De acordo com as análises por DRX e TGA, a maior parte dos hidratos se...
Blucher Design Proceedings, 2016
Journal of Civil Engineering and Architecture, 2015
Concrete is a widely used material in civil construction and may be submitted to high working tem... more Concrete is a widely used material in civil construction and may be submitted to high working temperatures under various circumstances. Many factors influence the behavior of this material at high temperatures, which usually leads to the evaporation of the hydrated cement. The dehydrated cement undergoes a contraction, simultaneously with the thermal expansion of the inert fraction of the material. As a consequence of these conflicting expansions and contractions, the material cracks and its strength and modulus of elasticity decrease significantly. On the other hand, the addition of short metallic fibers to the material increases its toughness, probably due to its action on the cracking behavior of the composite. It is thus expected that a concrete containing metallic fibers should maintain its original properties even after exposure to elevated temperatures. This paper presents an evaluation of the influence of steel fibers on the microstructure and toughness of concretes submitted to high temperatures. The bending behavior, under strain rate control, of concretes with a strength of 30 MPa and containing short steel fibers, submitted to a previous treatment at 500 °C, was analyzed. It was observed that, after both heat treatments, the addition of metallic fibers to concrete was able to maintain the pseudo-ductility and load-carrying capacity of this composite material.
Proceedings of the 3rd International Conference on Mechatronics, Robotics and Automation, 2015
The use of waste from both industrial and agricultural sources or from the construction sector it... more The use of waste from both industrial and agricultural sources or from the construction sector itself as alternative materials to partially or totally replace the aggregates or agglomerates of concrete/mortar has been an interesting option for obtaining eco-efficient cement compounds. The most commonly used wastes are blast furnace slag, silica fume, fly ash and waste from construction and demolition activities. Other interesting options are related to the use of sugarcane bagasse ash and glass waste. Despite the importance of cementitious compounds, there are few reports on their thermal performance, once the thermal comfort of the built environment is closely associated with the capacity of building materials to absorb, store and transmit heat to their interior. Published works indicate that replacing part of the cement with microparticles of soda-lime glass microparticles can contribute to the production of mortars and concretes of similar mechanical performance and workability, and the production of concretes durable in regard to the inhibition of the alkali-aggregate reaction. Accordingly, this study evaluated the thermal performance of mortars made with partial replacements of cement (10% and 20%) per colorless soda-lime glass microparticles and amber, and analyzed the results in relation to the surface temperature of materials after natural exposure to sunlight.
Rem: Revista Escola de Minas, 2012
Cementitious composites are commonly evaluated considering their workability, level of incorporat... more Cementitious composites are commonly evaluated considering their workability, level of incorporated air, elasticity modulus and compression strength. Data from compression testing commonly present a high dispersion, which has been attributed to effects of the specimen geometry, dimensions and of the degree of material compaction, as well as to problems in the specimen end-faces, such as their parallelism, orthogonality in relation to the compression axis and surface regularity. Specimen end-face regularization has been achieved through various techniques, such as adhering or non-adhering capping with various materials, mechanical grinding and systems involving special moulds. The regularization methods utilized more frequently employ sulfur mortar capping, neoprene cushions and surface grinding. The present work covers the experimental compression tests of cementitious composites of different classes of strength employing sulfur mortar capping and neoprene cushions. It was concluded...
Rem: Revista Escola de Minas, 2014
The effect of calcination temperature and air flow on the content of organic material, morphology... more The effect of calcination temperature and air flow on the content of organic material, morphology of particles, degree of crystallinity and the reactivity with lime solution of the sugar cane bagasse ash is evaluated. The results show that the long fibers of the bagasse and organic material are retained when calcination occurs without sufficient air flow. Calcining with forced air-flow breaks the fibers, removes organic material and produces fine particles at a temperature of 600ºC. The non-organic material observed in the ash displays a high degree of crystallinity. Experiments show that the crystalline structure observed in the ashes is due to adhered sand which was not previously washed away. The reduction on the conductivity in lime solution and X-rays diffraction pattern suggest that amorphous silica is formed at temperatures lower than 600ºC and cristobalite is formed at higher temperatures.
Research, Development and Practice in Structural Engineering and Construction, 2012
AC impedance spectroscopy was used to study the setting of alkali-activated geopolymers. Results ... more AC impedance spectroscopy was used to study the setting of alkali-activated geopolymers. Results show that electrochemical theory has certain advantages in analysis of the continuous microstructural changes of geopolymers in the process of geopolymerization.Setting process of alkali-activated geopolymer was divided into several stages according to the AC impedance spectra. AC impedance spectroscopy can be used to study the effect of the modulus and amount of activator on the microstructural change.
Materials Research, 2012
Grain refinement in magnesium is evaluated in the present paper. Equal Channel Angular Pressing i... more Grain refinement in magnesium is evaluated in the present paper. Equal Channel Angular Pressing is used to process commercially pure magnesium. Processing was carried out at 523 K which is lower than the temperature used in other papers on the literature. The grain structure was evaluated throughout the deformation zone. The low processing temperature prevents significant grain growth. The evolution of the grain structure is compared to a recent model for mechanism of grain refinement in magnesium. The present results confirm the validity of the model.
Journal of Materials Processing Technology, 2012
Metallic wires and bars are produced by axisymmetric drawing of hot rolled material and must not ... more Metallic wires and bars are produced by axisymmetric drawing of hot rolled material and must not display surface defects that impair their service use or whose opening during subsequent cold forming is unacceptable. Experimental and numerical (Finite Element Analysis-FEA) analyses of the evolution of longitudinal superficial defects in copper bars during seven successive axisymmetric drawing passes are presented. The initial experimental defects displayed a rectangular cross-section, 1 mm wide and 0.3, 0.6 or 0.9 mm deep; the two latter evolved after drawing into the "inverted Y" defect already reported in the literature, but the former led to a newly reported "double V" defect. There was a good agreement between the results from experiments and FEA and further analyses were then carried only through FEA, covering two other materials (a carbon steel and aluminum), a decrease in the defect width (from 1.0 to 0.5 mm) and an inclination of 15 • or 30 • of the walls of the 1.0 mm wide rectangular defect. The defect evolution was similar for the three materials; the decrease in the defect width enhanced the incidence of "inverted Y" defects, and indicated the formation of newly reported "Radial" and "Inverted V" defects. The inclination of the defect walls led to the possibility of a change from the "inverted Y" defect to a "double V" one. Defects 0.3 mm deep and with walls at 30 • were eliminated by the present drawing sequence. A novel approach for the prediction of the effect of the initial superficial imperfections on the final drawn stock, through the so called "defect evolution maps" is presented.
ISIJ International, 2008
In the present work, experimental techniques for evaluating the deformation and the redundant wor... more In the present work, experimental techniques for evaluating the deformation and the redundant work factor in the axisymmetric drawing of ferritic AISI 420 stainless steel bars were investigated. Six operation conditions, involving two reductions of area and three die semi-angles, were employed in the study. Regarding the redundant deformation analysis, the visioplasticity technique was considered as the most adequate procedure for estimating the average deformation in drawing. In this case, an increasing relationship between the redundant deformation factor and the parameter D was obtained. On the other hand, the stress-strain curves superposition technique led to redundant deformation factor values almost insensitive to variations of the parameter D and below unity, a phenomenon which was associated with strain path effects. Concerning the redundant work factor study, the experimental results were lower than those obtained through a theoretical approach and, in some conditions, below unity. This was also attributed to strain path effects.
PeerJ Materials Science
The potential applications of fungi in the development of new biomaterials derived from fungal my... more The potential applications of fungi in the development of new biomaterials derived from fungal mycelium have captured the attention from both the scientific community and the society. The notable ability of mycelium networks to self-construct and aggregate can be used to produce diverse biomaterials. These biomaterials can be created in a pure state, or both in conjunction with other organic/inorganic compounds. Recent advancements in mycomaterials have gained attention due to their sustainability and mechanical, thermogravimetric, and compression properties. Such properties contribute to reducing the reliance on environmentally problematic substrates within the industry. After a standardized and comprehensive review of publications on mycomaterials across different fields, such as biology, health, agriculture, engineering, and material sciences, we detected that publications on this theme are utterly scattered. This critical review enabled us to also propose a novel classification ...
In this study, activated carbon (AC) particles were combined with AZ91 alloy to manufacture a mag... more In this study, activated carbon (AC) particles were combined with AZ91 alloy to manufacture a magnesium syntactic foam. This novel lightweight foam has a very low density, in the range of 1.12-1.18 gcm −3. The results show that no chemical reaction occurred between the AZ91 matrix and the activated carbon particles. The mechanical properties of the foam were evaluated under quasi-static compression loading conditions, and showed a consistent trend for the energy absorption of the fabricated AZ91-AC syntactic foams. The deformation mechanism of samples was a brittle fracture mode with the formation of shear bands during the fracture of all samples.
A Construção Civil: em uma perspectivas econômica, ambiental e social
Quenching commonly causes a geometric distortion in the parts, associated with the thermal contra... more Quenching commonly causes a geometric distortion in the parts, associated with the thermal contraction and with the change in the mechanical and geometrical properties of austenite and martensite. It is of importance to predict the geometric behavior of mechanical components during heat treatment in order to improve the quality of the product, modifying the heat treatment process, or even defining a straightening process in order to correct the distortions. This study presents the finite element (FE) simulations of the quenching of AISI 4140 steel C-rings in oil and water. The severity of the water quenching was responsible for the larger distortion when compared to the oil water quenching process. The simulations are carried out with coupled analysis of heat transfer, deformation mechanics and phase transformations. In addition, hardness and phase transformation were conducted through numerical simulation.
ABM Proceedings, 2018
Resumo Os aços elétricos tem sido uma alternativa para aperfeiçoar a relação eficiência/perda mag... more Resumo Os aços elétricos tem sido uma alternativa para aperfeiçoar a relação eficiência/perda magnética dos equipamentos elétricos, sem a necessidade de grandes alterações de projeto Esses aços, também conhecidos como aços ao silício, podem ser de grão orientado ou não orientado, sendo suas propriedades, de modo geral, dependentes das diferentes condições adotadas para o processamento dos mesmos. Deste modo, considerando essa relação entre as condições de solicitação mecânica e o desempenho desses materiais este trabalho apresenta o estudo da resposta magnética exibida pelo aço de grão orientado após as chapas desse material serem submetidas à rota de processamento envolvendo a aplicação dos esforços de cisalhamento direto / cisalhamento reverso (cisalhamento cíclico). Os resultados indicaram a dependência das propriedades em função da quantidade de deformação plástica, ocasionando, de modo geral, o decaimento do desempenho magnético do mesmo. Palavras-chave: Aço GO; Ensaio Barkhausen; Cisalhamento cíclico, EFFECT OF CYCLIC SHEARING ON THE MAGNETIC PROPERTY OF GO STEEL
Materials Research, 2020
Severe plastic deformation (SPD) of metals leads to their strengthening and grain refinement, but... more Severe plastic deformation (SPD) of metals leads to their strengthening and grain refinement, but to low uniform elongations. Low Strain Amplitude Multi Directional Forging (LSA-MDF) is an important method for increasing this low uniform elongation. The application of workpieces of SPD-processed materials requires that their distributions of mechanical properties, microstructures and deformation be as homogeneous as possible. Analyses of these distributions after LSA-MDF have not been found in the literature, and are presented in the current investigation utilizing microhardness measurements, optical and electronic microscopy and finite element simulations. LSA-MDF causes higher strains, mcrohardeness and structural distortions in the central regions of the specimens than at their edges and corners. In addition, LSA-MDF utilizing confined compressions seems to be the preferred processing route, due to its ease and to the more homogeneous microhardness, microstructure and strain distributions in relation to other experimental procedures.
Matéria (Rio de Janeiro), 2020
RESUMO O vidro soda-cal-sílica é um material com alto potencial de reciclagem. No entanto, o seu ... more RESUMO O vidro soda-cal-sílica é um material com alto potencial de reciclagem. No entanto, o seu beneficiamento gera micropartículas que ficam suspensas na água utilizada para resfriamento das ferramentas. Esse resíduo é inerte e, comumente, não reaproveitado. Para seu descarte é feita a decantação das micropartículas de vidro utilizando floculantes, sendo a lama produzida depositada em aterros sanitários. De acordo com a literatura, essas micropartículas de vidro poderiam atuar como material cimentício suplementar na produção de cimento Portland. Contudo, as informações sobre o desempenho térmico desses materiais são escassas. Neste estudo investiga-se a difusividade térmica de argamassas para fins estruturais confeccionadas com cimento Portland e lama de vidro soda-cal-sílica com características pozolânicas. Foram produzidas argamassas com e sem substituição do cimento por 10 e 20% de lama in natura e lama lavada para retirada do floculante. As argamassas foram caracterizadas quan...
Matéria (Rio de Janeiro), 2020
RESUMO Um método alternativo para produção de concretos ecoeficientes seria a substituição parcia... more RESUMO Um método alternativo para produção de concretos ecoeficientes seria a substituição parcial de cimento Portland por resíduos de pastas e argamassas submetidas a um tratamento termomecânico. Neste contexto, este estudo avalia a influência da relação água/cimento (a/c) e do tamanho médio das partículas na decomposição térmica do cimento hidratado. Pastas de cimento com três relações a/c (0,40, 0,50 e 0,60) e curadas por 28 dias foram moídas para obtenção de granulometrias com tamanho médio de 0,60 mm e 0,15 mm. A decomposição térmica das pastas foi analisada por termogravimetria (TGA), difração de raios X (DRX) e espectroscopia no infravermelho por Transformada de Fourier (FTIR). A análise de TGA indica que o teor de água quimicamente combinada é favorecido pelo aumento da relação a/c entre 0,40 e 0,50, mas é constante para a/c de 0,50 e 0,60. A redução do tamanho médio quase não interfere nas curvas de TGA. De acordo com as análises por DRX e TGA, a maior parte dos hidratos se...
Blucher Design Proceedings, 2016
Journal of Civil Engineering and Architecture, 2015
Concrete is a widely used material in civil construction and may be submitted to high working tem... more Concrete is a widely used material in civil construction and may be submitted to high working temperatures under various circumstances. Many factors influence the behavior of this material at high temperatures, which usually leads to the evaporation of the hydrated cement. The dehydrated cement undergoes a contraction, simultaneously with the thermal expansion of the inert fraction of the material. As a consequence of these conflicting expansions and contractions, the material cracks and its strength and modulus of elasticity decrease significantly. On the other hand, the addition of short metallic fibers to the material increases its toughness, probably due to its action on the cracking behavior of the composite. It is thus expected that a concrete containing metallic fibers should maintain its original properties even after exposure to elevated temperatures. This paper presents an evaluation of the influence of steel fibers on the microstructure and toughness of concretes submitted to high temperatures. The bending behavior, under strain rate control, of concretes with a strength of 30 MPa and containing short steel fibers, submitted to a previous treatment at 500 °C, was analyzed. It was observed that, after both heat treatments, the addition of metallic fibers to concrete was able to maintain the pseudo-ductility and load-carrying capacity of this composite material.
Proceedings of the 3rd International Conference on Mechatronics, Robotics and Automation, 2015
The use of waste from both industrial and agricultural sources or from the construction sector it... more The use of waste from both industrial and agricultural sources or from the construction sector itself as alternative materials to partially or totally replace the aggregates or agglomerates of concrete/mortar has been an interesting option for obtaining eco-efficient cement compounds. The most commonly used wastes are blast furnace slag, silica fume, fly ash and waste from construction and demolition activities. Other interesting options are related to the use of sugarcane bagasse ash and glass waste. Despite the importance of cementitious compounds, there are few reports on their thermal performance, once the thermal comfort of the built environment is closely associated with the capacity of building materials to absorb, store and transmit heat to their interior. Published works indicate that replacing part of the cement with microparticles of soda-lime glass microparticles can contribute to the production of mortars and concretes of similar mechanical performance and workability, and the production of concretes durable in regard to the inhibition of the alkali-aggregate reaction. Accordingly, this study evaluated the thermal performance of mortars made with partial replacements of cement (10% and 20%) per colorless soda-lime glass microparticles and amber, and analyzed the results in relation to the surface temperature of materials after natural exposure to sunlight.
Rem: Revista Escola de Minas, 2012
Cementitious composites are commonly evaluated considering their workability, level of incorporat... more Cementitious composites are commonly evaluated considering their workability, level of incorporated air, elasticity modulus and compression strength. Data from compression testing commonly present a high dispersion, which has been attributed to effects of the specimen geometry, dimensions and of the degree of material compaction, as well as to problems in the specimen end-faces, such as their parallelism, orthogonality in relation to the compression axis and surface regularity. Specimen end-face regularization has been achieved through various techniques, such as adhering or non-adhering capping with various materials, mechanical grinding and systems involving special moulds. The regularization methods utilized more frequently employ sulfur mortar capping, neoprene cushions and surface grinding. The present work covers the experimental compression tests of cementitious composites of different classes of strength employing sulfur mortar capping and neoprene cushions. It was concluded...
Rem: Revista Escola de Minas, 2014
The effect of calcination temperature and air flow on the content of organic material, morphology... more The effect of calcination temperature and air flow on the content of organic material, morphology of particles, degree of crystallinity and the reactivity with lime solution of the sugar cane bagasse ash is evaluated. The results show that the long fibers of the bagasse and organic material are retained when calcination occurs without sufficient air flow. Calcining with forced air-flow breaks the fibers, removes organic material and produces fine particles at a temperature of 600ºC. The non-organic material observed in the ash displays a high degree of crystallinity. Experiments show that the crystalline structure observed in the ashes is due to adhered sand which was not previously washed away. The reduction on the conductivity in lime solution and X-rays diffraction pattern suggest that amorphous silica is formed at temperatures lower than 600ºC and cristobalite is formed at higher temperatures.
Research, Development and Practice in Structural Engineering and Construction, 2012
AC impedance spectroscopy was used to study the setting of alkali-activated geopolymers. Results ... more AC impedance spectroscopy was used to study the setting of alkali-activated geopolymers. Results show that electrochemical theory has certain advantages in analysis of the continuous microstructural changes of geopolymers in the process of geopolymerization.Setting process of alkali-activated geopolymer was divided into several stages according to the AC impedance spectra. AC impedance spectroscopy can be used to study the effect of the modulus and amount of activator on the microstructural change.
Materials Research, 2012
Grain refinement in magnesium is evaluated in the present paper. Equal Channel Angular Pressing i... more Grain refinement in magnesium is evaluated in the present paper. Equal Channel Angular Pressing is used to process commercially pure magnesium. Processing was carried out at 523 K which is lower than the temperature used in other papers on the literature. The grain structure was evaluated throughout the deformation zone. The low processing temperature prevents significant grain growth. The evolution of the grain structure is compared to a recent model for mechanism of grain refinement in magnesium. The present results confirm the validity of the model.
Journal of Materials Processing Technology, 2012
Metallic wires and bars are produced by axisymmetric drawing of hot rolled material and must not ... more Metallic wires and bars are produced by axisymmetric drawing of hot rolled material and must not display surface defects that impair their service use or whose opening during subsequent cold forming is unacceptable. Experimental and numerical (Finite Element Analysis-FEA) analyses of the evolution of longitudinal superficial defects in copper bars during seven successive axisymmetric drawing passes are presented. The initial experimental defects displayed a rectangular cross-section, 1 mm wide and 0.3, 0.6 or 0.9 mm deep; the two latter evolved after drawing into the "inverted Y" defect already reported in the literature, but the former led to a newly reported "double V" defect. There was a good agreement between the results from experiments and FEA and further analyses were then carried only through FEA, covering two other materials (a carbon steel and aluminum), a decrease in the defect width (from 1.0 to 0.5 mm) and an inclination of 15 • or 30 • of the walls of the 1.0 mm wide rectangular defect. The defect evolution was similar for the three materials; the decrease in the defect width enhanced the incidence of "inverted Y" defects, and indicated the formation of newly reported "Radial" and "Inverted V" defects. The inclination of the defect walls led to the possibility of a change from the "inverted Y" defect to a "double V" one. Defects 0.3 mm deep and with walls at 30 • were eliminated by the present drawing sequence. A novel approach for the prediction of the effect of the initial superficial imperfections on the final drawn stock, through the so called "defect evolution maps" is presented.
ISIJ International, 2008
In the present work, experimental techniques for evaluating the deformation and the redundant wor... more In the present work, experimental techniques for evaluating the deformation and the redundant work factor in the axisymmetric drawing of ferritic AISI 420 stainless steel bars were investigated. Six operation conditions, involving two reductions of area and three die semi-angles, were employed in the study. Regarding the redundant deformation analysis, the visioplasticity technique was considered as the most adequate procedure for estimating the average deformation in drawing. In this case, an increasing relationship between the redundant deformation factor and the parameter D was obtained. On the other hand, the stress-strain curves superposition technique led to redundant deformation factor values almost insensitive to variations of the parameter D and below unity, a phenomenon which was associated with strain path effects. Concerning the redundant work factor study, the experimental results were lower than those obtained through a theoretical approach and, in some conditions, below unity. This was also attributed to strain path effects.
PeerJ Materials Science
The potential applications of fungi in the development of new biomaterials derived from fungal my... more The potential applications of fungi in the development of new biomaterials derived from fungal mycelium have captured the attention from both the scientific community and the society. The notable ability of mycelium networks to self-construct and aggregate can be used to produce diverse biomaterials. These biomaterials can be created in a pure state, or both in conjunction with other organic/inorganic compounds. Recent advancements in mycomaterials have gained attention due to their sustainability and mechanical, thermogravimetric, and compression properties. Such properties contribute to reducing the reliance on environmentally problematic substrates within the industry. After a standardized and comprehensive review of publications on mycomaterials across different fields, such as biology, health, agriculture, engineering, and material sciences, we detected that publications on this theme are utterly scattered. This critical review enabled us to also propose a novel classification ...
In this study, activated carbon (AC) particles were combined with AZ91 alloy to manufacture a mag... more In this study, activated carbon (AC) particles were combined with AZ91 alloy to manufacture a magnesium syntactic foam. This novel lightweight foam has a very low density, in the range of 1.12-1.18 gcm −3. The results show that no chemical reaction occurred between the AZ91 matrix and the activated carbon particles. The mechanical properties of the foam were evaluated under quasi-static compression loading conditions, and showed a consistent trend for the energy absorption of the fabricated AZ91-AC syntactic foams. The deformation mechanism of samples was a brittle fracture mode with the formation of shear bands during the fracture of all samples.