Pub Date : 2020-08-28DOI: 10.17265/2161-6221/2020.7-8.001
C. Burkhardt, A. Lehmann, B. Podmiljšak, S. Kobe
Availability of magnetic materials is most crucial for modern Europe, as they are integral to energy conversion across the renewable energy and electric mobility sectors. Unfortunately, there is still no circular economy to reuse and capture value for these types of materials. With the prediction that the need for NdFeB Rare Earth (RE) magnets will double in the next 10 years, this problem becomes even more urgent. As the quality of the recollected materials varies significantly, the development of a classification system for recyclate grades of EOL NdFeB magnets in combination with an eco-labelling system for newly produced RE permanent magnets is proposed to clearly identify different magnet types and qualities. It categorises the NdFeB magnets by technical pre-processing requirements, facilitating use of the highly effective HPMS process (Hydrogen Processing of Magnetic Scrap) for re-processing extracted materials directly from NdFeB alloy. The proposed measures will have a great impact to overcome existing low recycling rates due to poor collection, high leakages of collected materials into non-suitable channels, and inappropriate interface management between logistics, mechanical pre-processing and metallurgical metals recovery.
{"title":"A Systematic Classification and Labelling Approach to Support a Circular Economy Ecosystem for NdFeB-Type Magnet","authors":"C. Burkhardt, A. Lehmann, B. Podmiljšak, S. Kobe","doi":"10.17265/2161-6221/2020.7-8.001","DOIUrl":"https://doi.org/10.17265/2161-6221/2020.7-8.001","url":null,"abstract":"Availability of magnetic materials is most crucial for modern Europe, as they are integral to energy conversion across the renewable energy and electric mobility sectors. Unfortunately, there is still no circular economy to reuse and capture value for these types of materials. With the prediction that the need for NdFeB Rare Earth (RE) magnets will double in the next 10 years, this problem becomes even more urgent. As the quality of the recollected materials varies significantly, the development of a classification system for recyclate grades of EOL NdFeB magnets in combination with an eco-labelling system for newly produced RE permanent magnets is proposed to clearly identify different magnet types and qualities. It categorises the NdFeB magnets by technical pre-processing requirements, facilitating use of the highly effective HPMS process (Hydrogen Processing of Magnetic Scrap) for re-processing extracted materials directly from NdFeB alloy. The proposed measures will have a great impact to overcome existing low recycling rates due to poor collection, high leakages of collected materials into non-suitable channels, and inappropriate interface management between logistics, mechanical pre-processing and metallurgical metals recovery.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90858383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The behavior of S235 metal, a general purpose metal construction material in Senegal, has been studied in perchloric acid solution in the presence of gum arabic from Senegal as a corrosion inhibitor. The protective power of this compound has been evaluated by electrochemical methods (stationary polarization curves and electrochemical impedance spectroscopy), at different inhibitor contents. We have considered testing gum arabic as an aqueous corrosion inhibitor. Electrochemical tests show that the values of the corrosion parameters vary with the content of gum arabic. An optimal inhibitory efficacy of approximately 88% is obtained for this substance, thus demonstrating the inhibitory nature.
{"title":"Influence of the Inhibition of Corrosion of S235 Steel in a Solution of Perchloric Acid by Gum Arabic","authors":"Khaly Cissé, D. Gassama, A. Diagne, M. Badji","doi":"10.12691/AJMSE-8-1-3","DOIUrl":"https://doi.org/10.12691/AJMSE-8-1-3","url":null,"abstract":"The behavior of S235 metal, a general purpose metal construction material in Senegal, has been studied in perchloric acid solution in the presence of gum arabic from Senegal as a corrosion inhibitor. The protective power of this compound has been evaluated by electrochemical methods (stationary polarization curves and electrochemical impedance spectroscopy), at different inhibitor contents. We have considered testing gum arabic as an aqueous corrosion inhibitor. Electrochemical tests show that the values of the corrosion parameters vary with the content of gum arabic. An optimal inhibitory efficacy of approximately 88% is obtained for this substance, thus demonstrating the inhibitory nature.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"37 1","pages":"17-21"},"PeriodicalIF":0.0,"publicationDate":"2020-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86831884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-28DOI: 10.17265/2161-6213/2020.5-6.001
Nicole Araujo, Marília Bortolotto, M. Silva, M. Nava, P. C. Lima, E. Lima
The present research aimed to analyze the influence that different contents of titanium (x = 0.5, 0.6 and 0.7 wt.%) have on the martensitic transformation temperature of a Cu-14Al-4Ni (wt.%) SMA (shape memory alloy). The Cu-14Al-4Ni-xTi samples were casted in an arc-melting furnace and rapidly solidified. All samples underwent heat treatment in a tubular furnace at a temperature of 1,100 °C for 30 min and water quenched at 25 °C. Subsequently, samples were analyzed by SEM (scanning electron microscopy) with EDS (energy dispersive spectroscopy), XRD (X-ray diffraction) and DSC (differential scanning calorimeter). SEM images and XRD patterns showed that the presence of titanium modified the alloy’s microstructure, induced the formation of three titanium rich phases called “X” phase (CuNi2Ti, Cu3Ti and AlCu2Ti) and reduced the presence of the brittle phase γ2 (Cu9Al4) for samples with 0.6 and 0.7 wt.% Ti. The titanium added to the copper based SMA also functioned as a refiner, reducing GS (grain size) up to approximately 80% with the increase of Ti content. DSC results exhibited low enthalpy levels, hysteresis, as well as low start martensitic transformation temperatures.
{"title":"Effect of Titanium on the Martensitic Transformation Temperature of Cu-14Al-4Ni Shape Memory Alloy Rapidly Solidified","authors":"Nicole Araujo, Marília Bortolotto, M. Silva, M. Nava, P. C. Lima, E. Lima","doi":"10.17265/2161-6213/2020.5-6.001","DOIUrl":"https://doi.org/10.17265/2161-6213/2020.5-6.001","url":null,"abstract":"The present research aimed to analyze the influence that different contents of titanium (x = 0.5, 0.6 and 0.7 wt.%) have on the martensitic transformation temperature of a Cu-14Al-4Ni (wt.%) SMA (shape memory alloy). The Cu-14Al-4Ni-xTi samples were casted in an arc-melting furnace and rapidly solidified. All samples underwent heat treatment in a tubular furnace at a temperature of 1,100 °C for 30 min and water quenched at 25 °C. Subsequently, samples were analyzed by SEM (scanning electron microscopy) with EDS (energy dispersive spectroscopy), XRD (X-ray diffraction) and DSC (differential scanning calorimeter). SEM images and XRD patterns showed that the presence of titanium modified the alloy’s microstructure, induced the formation of three titanium rich phases called “X” phase (CuNi2Ti, Cu3Ti and AlCu2Ti) and reduced the presence of the brittle phase γ2 (Cu9Al4) for samples with 0.6 and 0.7 wt.% Ti. The titanium added to the copper based SMA also functioned as a refiner, reducing GS (grain size) up to approximately 80% with the increase of Ti content. DSC results exhibited low enthalpy levels, hysteresis, as well as low start martensitic transformation temperatures.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84129571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-28DOI: 10.17265/2161-6221/2020.5-6.001
P. F. Yao, S. Li, R. Liu
ASTM F75 is a low-carbon CoCrMo alloy which has been used as hip implant material for decades, but the ASTM F75 implants can fail when the femoral head and the acetabular cup loosen because of limited metal-on-metal bearing. Therefore, a modified version of ASTM F75 alloy which has 90 wt.% ASTM F75 plus 10 wt.% Cr is proposed. The wear and corrosion resistance of both alloys are investigated simulating the working environment of hip implants in human body. The mechanics behavior of the femoral implant under the loading condition in human body with ASTM F75 or modified ASTM F75 material used is studied with FEA simulation. The cytotoxicity (MTT) assays of the alloys are measured and compared to that of inert ceramic and cytotoxic cobalt. The experimental and simulation results show that the proposed alloy exhibits better wear and corrosion resistance than the conventional hip implant material. Both alloys behave well with respect to stress and deformation when used for the femoral implant under the loading condition in human body. These two alloys display similar cytotoxicity performance to inert ceramic.
{"title":"Performance Characterization of Modified ASTM F75 Alloy for Hip Implant Application","authors":"P. F. Yao, S. Li, R. Liu","doi":"10.17265/2161-6221/2020.5-6.001","DOIUrl":"https://doi.org/10.17265/2161-6221/2020.5-6.001","url":null,"abstract":"ASTM F75 is a low-carbon CoCrMo alloy which has been used as hip implant material for decades, but the ASTM F75 implants can fail when the femoral head and the acetabular cup loosen because of limited metal-on-metal bearing. Therefore, a modified version of ASTM F75 alloy which has 90 wt.% ASTM F75 plus 10 wt.% Cr is proposed. The wear and corrosion resistance of both alloys are investigated simulating the working environment of hip implants in human body. The mechanics behavior of the femoral implant under the loading condition in human body with ASTM F75 or modified ASTM F75 material used is studied with FEA simulation. The cytotoxicity (MTT) assays of the alloys are measured and compared to that of inert ceramic and cytotoxic cobalt. The experimental and simulation results show that the proposed alloy exhibits better wear and corrosion resistance than the conventional hip implant material. Both alloys behave well with respect to stress and deformation when used for the femoral implant under the loading condition in human body. These two alloys display similar cytotoxicity performance to inert ceramic.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"261 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91476475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-28DOI: 10.17265/2161-6221/2020.5-6.003
Mariame Conde Asseng, Hermann Tamaguelon Dzoujo, Daniela Dina, Marie-Annie Etoh, Armand N. Tchakounte, J. N. Nsami
The study of the performances of regenerated activated carbons for the adsorption of MO (methyl orange) in an aqueous medium was carried out with the aim to evaluate the adsorption capacities of these activated carbons. Three regenerated activated carbons issued from the unit of oil treatment of the thermal power station of Dibamba (Cameroon)-DPDC (Dibamba Power Development Company) were obtained thermally and chemically. These three samples (namely CAR 400 °C (chemical regenerated activated carbon at 400 °C), CAR 700 °C (physical regenerated activated carbon at 700 °C) and CAR 900 °C (physical regenerated activated carbon at 900 °C)) and the non-used one CA were characterized by iodine number, XRD (X-ray Diffraction) and FTIR (Fourier-transform infrared spectroscopy). MO adsorption tests were performed in batch mode; this technique allowed the study of the influence of the parameters such as: the contact time, the initial’s MO concentration and the pH. Moreover, different kinetic models (first-order, pseudo-second-order and Webber and Morris intra-particle diffusion) and adsorption isotherms (Langmuir and Freundlich) are used for the evaluation of adsorption capacities. The physicochemical characterization of these adsorbents showed that they were micro-porous (iodine value: 600 mg/g) and strongly crystallized according to their regeneration pathways. The influence of the parameters revealed that the adsorption of MO is the most favorable for concentrations from 5 to 25 mg/L (for materials CA and CAR 400 °C) and 10 to 25 g/L (for materials CAR 700 °C and 900 °C); and that it was maximum in acid medium (at pH = 3 on the materials CA, CAR 400 °C, CAR 900 °C and at pH = 5 on the material CAR 900 °C). The modeling of the adsorption kinetics of MO has revealed the conformity of the kinetic model of pseudosecond-order and intra-particle diffusion for some of these materials. The study of isotherms has shown that the Langmuir isotherm best describes the adsorption of MO on most of these adsorbents.
{"title":"Batch Studies for the Removal of a Hazardous Azo Dye Methyl Orange from Water through Adsorption on Regenerated Activated Carbons","authors":"Mariame Conde Asseng, Hermann Tamaguelon Dzoujo, Daniela Dina, Marie-Annie Etoh, Armand N. Tchakounte, J. N. Nsami","doi":"10.17265/2161-6221/2020.5-6.003","DOIUrl":"https://doi.org/10.17265/2161-6221/2020.5-6.003","url":null,"abstract":"The study of the performances of regenerated activated carbons for the adsorption of MO (methyl orange) in an aqueous medium was carried out with the aim to evaluate the adsorption capacities of these activated carbons. Three regenerated activated carbons issued from the unit of oil treatment of the thermal power station of Dibamba (Cameroon)-DPDC (Dibamba Power Development Company) were obtained thermally and chemically. These three samples (namely CAR 400 °C (chemical regenerated activated carbon at 400 °C), CAR 700 °C (physical regenerated activated carbon at 700 °C) and CAR 900 °C (physical regenerated activated carbon at 900 °C)) and the non-used one CA were characterized by iodine number, XRD (X-ray Diffraction) and FTIR (Fourier-transform infrared spectroscopy). MO adsorption tests were performed in batch mode; this technique allowed the study of the influence of the parameters such as: the contact time, the initial’s MO concentration and the pH. Moreover, different kinetic models (first-order, pseudo-second-order and Webber and Morris intra-particle diffusion) and adsorption isotherms (Langmuir and Freundlich) are used for the evaluation of adsorption capacities. The physicochemical characterization of these adsorbents showed that they were micro-porous (iodine value: 600 mg/g) and strongly crystallized according to their regeneration pathways. The influence of the parameters revealed that the adsorption of MO is the most favorable for concentrations from 5 to 25 mg/L (for materials CA and CAR 400 °C) and 10 to 25 g/L (for materials CAR 700 °C and 900 °C); and that it was maximum in acid medium (at pH = 3 on the materials CA, CAR 400 °C, CAR 900 °C and at pH = 5 on the material CAR 900 °C). The modeling of the adsorption kinetics of MO has revealed the conformity of the kinetic model of pseudosecond-order and intra-particle diffusion for some of these materials. The study of isotherms has shown that the Langmuir isotherm best describes the adsorption of MO on most of these adsorbents.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"79 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74084957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. A. Tigori, A. Kouyaté, Assouma Dagri Cyrille, Victorien Kouakou, P. Niamien
The behavior of two antidiabetic drugs namely N-[(butylamino) carbonyl]-4-methylbenzenesulfonamide or tolbutamide and N-(hexahydrocyclopentapyrrol-2(1H)-ylcarbamoyl)-4-methylbenzenesulfonamide or gliclazide was theoretically evaluated by the Density Functional Theory (DFT) and the Quantitative Structure Property Relationship (QSPR) methods. Theoretical calculations showed a clear correlation between the descriptor parameters and the inhibition efficicencies. It also permitted to identify the reactivity sites. The results reveal that the molecules studied are good inhibitors of aluminium corrosion in 1M hydrochloric acid. Finally, the Quantitative Structure Property Relationship allowed to find the appropriate set of parameters establishing the relationship between the inhibition efficiency and the molecular descriptors.
{"title":"Theoretical Investigation of Two Antiabetics Drugs as Corrosion Inhibitors of Aluminium in 1.0 M HCl: Combining DFT and QSPR Calculations","authors":"M. A. Tigori, A. Kouyaté, Assouma Dagri Cyrille, Victorien Kouakou, P. Niamien","doi":"10.12691/AJMSE-8-1-2","DOIUrl":"https://doi.org/10.12691/AJMSE-8-1-2","url":null,"abstract":"The behavior of two antidiabetic drugs namely N-[(butylamino) carbonyl]-4-methylbenzenesulfonamide or tolbutamide and N-(hexahydrocyclopentapyrrol-2(1H)-ylcarbamoyl)-4-methylbenzenesulfonamide or gliclazide was theoretically evaluated by the Density Functional Theory (DFT) and the Quantitative Structure Property Relationship (QSPR) methods. Theoretical calculations showed a clear correlation between the descriptor parameters and the inhibition efficicencies. It also permitted to identify the reactivity sites. The results reveal that the molecules studied are good inhibitors of aluminium corrosion in 1M hydrochloric acid. Finally, the Quantitative Structure Property Relationship allowed to find the appropriate set of parameters establishing the relationship between the inhibition efficiency and the molecular descriptors.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"26 1","pages":"6-16"},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77498762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-28DOI: 10.17265/2161-6221/2020.5-6.002
Оblokul Кuvadikovich Кuvadikov, N. S. Hamraev, A. Eshkulov, R. M. Rajabov
Normal, R0, and anomalous, RS, components of the Hall coefficient are determined from the results of experimental investigations of temperature dependences of the Hall coefficient, magnetic susceptibility, and specific electrical resistance for intermetallic Gd3In, Gd3In5 and GdIn3 compounds. Effective parameters of spin-orbital interaction SO of intermetallic compounds are calculated from anomalous components RS of the Hall coefficient and specific electrical resistance. The results calculated for the band parameters and effective parameters of spin-orbital interaction SO for Gd-In system intermetallides coincide by orders of magnitude with the results obtained from the optical spectra of pure REMs (rare-earth metals).
{"title":"The Research of Spin-Orbital Interaction in Intermetallic Compounds of System Gd-In on Paramagnetic Area","authors":"Оblokul Кuvadikovich Кuvadikov, N. S. Hamraev, A. Eshkulov, R. M. Rajabov","doi":"10.17265/2161-6221/2020.5-6.002","DOIUrl":"https://doi.org/10.17265/2161-6221/2020.5-6.002","url":null,"abstract":"Normal, R0, and anomalous, RS, components of the Hall coefficient are determined from the results of experimental investigations of temperature dependences of the Hall coefficient, magnetic susceptibility, and specific electrical resistance for intermetallic Gd3In, Gd3In5 and GdIn3 compounds. Effective parameters of spin-orbital interaction SO of intermetallic compounds are calculated from anomalous components RS of the Hall coefficient and specific electrical resistance. The results calculated for the band parameters and effective parameters of spin-orbital interaction SO for Gd-In system intermetallides coincide by orders of magnitude with the results obtained from the optical spectra of pure REMs (rare-earth metals).","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82365255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The toupie is a ready concrete delivery truck (BPE). Accidentally or negligently, if the concrete is not delivered on time, he makes and hardens. It enters the range of waste. In this study, fresh concrete is crushed and reused as a substitute for natural aggregates. A 2-variable experience plan (% sand and% gravel) was used to reduce the number of measurements. The replacement proportions used are 0%, 50% and 100%. Several mechanical and physical properties were measured including compressive strength, tensile strength and absorption. These results show a good correlation between the percentage of replacement and the properties of this concrete. Replacing 50% of natural aggregates (sand and gravel) with recycled aggregates results in a reduction of about 24% in the compressive strength of the concrete under test.
{"title":"Recycled Concrete Based on Retour de Toupie Aggregates (Fresh Concrete Waste)","authors":"Serifou Mamery Adama, Jolissaint Obre Sery Paul, A. Alexandre, Emeruwa Edjikémé","doi":"10.12691/AJMSE-8-1-1","DOIUrl":"https://doi.org/10.12691/AJMSE-8-1-1","url":null,"abstract":"The toupie is a ready concrete delivery truck (BPE). Accidentally or negligently, if the concrete is not delivered on time, he makes and hardens. It enters the range of waste. In this study, fresh concrete is crushed and reused as a substitute for natural aggregates. A 2-variable experience plan (% sand and% gravel) was used to reduce the number of measurements. The replacement proportions used are 0%, 50% and 100%. Several mechanical and physical properties were measured including compressive strength, tensile strength and absorption. These results show a good correlation between the percentage of replacement and the properties of this concrete. Replacing 50% of natural aggregates (sand and gravel) with recycled aggregates results in a reduction of about 24% in the compressive strength of the concrete under test.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"13 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82153813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-28DOI: 10.17265/2161-6213/2020.3-4.005
M. Nava, E. Lima, P. C. Lima
The non-ferrous SMAs (shape memory alloys) have, normally, two problems that hinder the use in industrial scale: the natural aging and grain growth. The first degrades the memory effect, while the second, observed during the alloy’s mechanical processing, modifies the phase transformation temperatures. Thus, the study of recrystallization kinetics is important for enabling the control of hardened state as a function of treatment time without allowing the exaggerated grain growth. The objective of this study is to determine the recrystallization kinetics in different SMAs (Cu-14Al-4Ni, Cu-12Al-0.5Be and Ni-42Ti), based on an empirical law of J-M-A (Johnson-Mehl-Avrami), as well as their activation energies for grain growth process according to the empirical Arrhenius law.Quantitative evaluations of the grain growth kinetics over a wide range of indicated DSC (differential scanning calorimetry) temperatures have been performed. The results show that the alloy less susceptible to aging in temperatures below the recrystallization peak is the Ni-42Ti, because it presented the highest activation energy, followed by the Cu-14Al-4Ni. The equations that describe the recrystallization kinetics follow the empirical law of J-M-A. The recrystallization kinetics accompanied by hardness variation was an important tool, working as an advisor for selection of treatment time as a function of temperature.
{"title":"Comparisson of Recrystallization Kinetics and Grain Growth in Polycrystalline Shape Memory Alloys","authors":"M. Nava, E. Lima, P. C. Lima","doi":"10.17265/2161-6213/2020.3-4.005","DOIUrl":"https://doi.org/10.17265/2161-6213/2020.3-4.005","url":null,"abstract":"The non-ferrous SMAs (shape memory alloys) have, normally, two problems that hinder the use in industrial scale: the natural aging and grain growth. The first degrades the memory effect, while the second, observed during the alloy’s mechanical processing, modifies the phase transformation temperatures. Thus, the study of recrystallization kinetics is important for enabling the control of hardened state as a function of treatment time without allowing the exaggerated grain growth. The objective of this study is to determine the recrystallization kinetics in different SMAs (Cu-14Al-4Ni, Cu-12Al-0.5Be and Ni-42Ti), based on an empirical law of J-M-A (Johnson-Mehl-Avrami), as well as their activation energies for grain growth process according to the empirical Arrhenius law.Quantitative evaluations of the grain growth kinetics over a wide range of indicated DSC (differential scanning calorimetry) temperatures have been performed. The results show that the alloy less susceptible to aging in temperatures below the recrystallization peak is the Ni-42Ti, because it presented the highest activation energy, followed by the Cu-14Al-4Ni. The equations that describe the recrystallization kinetics follow the empirical law of J-M-A. The recrystallization kinetics accompanied by hardness variation was an important tool, working as an advisor for selection of treatment time as a function of temperature.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"99 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80569712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-28DOI: 10.17265/2161-6213/2020.3-4.002
Daniel Diehl, Carlos Roberto Köhler, E. L. Schneider, T. Clarke
Precipitation-hardened aluminum alloys need to be heat treated to achieve the mechanical properties required for their application. The production of these materials can be optimized to make them more attractive and competitive comparing to other materials such as composites that have a growing and large market share in aeronautics field. One way to do this is by controlling the artificial aging of precipitation-hardenable aluminum alloys, such as the 2000 series Al-Cu alloys. These alloys can be monitored in real time by analyzing their conductivity behavior inside the furnace. The objective of this work is to evaluate the electrical conductivity behavior in real time of the 2024 alloy during the artificial aging at 190 °C. For this, analyses were made in order to assess the behavior of the microhardness curve by aging time and its microstructural characterization with thermal treatments in the times of 1 h to 9 h interrupted every 1 h. The results of the electrical conductivity versus hardness curve showed a significant correlation and indicate that this measure has great potential to be used as a tool to control the thermal treatment of aging.
{"title":"Electrical Conductivity Behavior of the Aluminum Alloy 2024 during Artificial Aging","authors":"Daniel Diehl, Carlos Roberto Köhler, E. L. Schneider, T. Clarke","doi":"10.17265/2161-6213/2020.3-4.002","DOIUrl":"https://doi.org/10.17265/2161-6213/2020.3-4.002","url":null,"abstract":"Precipitation-hardened aluminum alloys need to be heat treated to achieve the mechanical properties required for their application. The production of these materials can be optimized to make them more attractive and competitive comparing to other materials such as composites that have a growing and large market share in aeronautics field. One way to do this is by controlling the artificial aging of precipitation-hardenable aluminum alloys, such as the 2000 series Al-Cu alloys. These alloys can be monitored in real time by analyzing their conductivity behavior inside the furnace. The objective of this work is to evaluate the electrical conductivity behavior in real time of the 2024 alloy during the artificial aging at 190 °C. For this, analyses were made in order to assess the behavior of the microhardness curve by aging time and its microstructural characterization with thermal treatments in the times of 1 h to 9 h interrupted every 1 h. The results of the electrical conductivity versus hardness curve showed a significant correlation and indicate that this measure has great potential to be used as a tool to control the thermal treatment of aging.","PeriodicalId":16171,"journal":{"name":"Journal of materials science & engineering","volume":"2016 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86333400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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