B. Karpe, Katarina Kern, J. Kovač, M. Klanjšek Gunde, A. Nagode, M. Bizjak, M. Zorc
Scandium (Sc) is known to be one of the most effective alloying elements of aluminum alloys. The only drawback is its high price, but that could change quickly due to the promising results of recent research on its extraction. However, the data on how it affects anodic oxidation are very scarce. In this research, we analyzed how a micro-addition of Sc to the AlMg alloy affects the growth mechanism and properties of the protective aluminium oxide layer depending on the anodization parameters. For comparison, alloy AA5083 with a similar magnesium content was also anodized with the same anodizing parameters. In all experiments, sulfuric acid (VI) with concentrations of 1.72 M or 2.2 M at temperatures of 21 °C or 35 °C was used as the electrolyte. Potentiostatic (18 V) and galvanostatic (20 mA/cm2) anodizing methods were applied. The results (SED-EDS) show that scandium is uniformly intercalated in the matrix of the oxide layer and decreases its resistivity, which increases the oxide growth rate during potentiostatic anodizing and decreases the pore density and pore diameters during galvanostatic anodizing. Moreover, it increases the mobility of cations through the oxide layer, thus accelerating the oxidation reaction in concentrated sulfuric acid electrolytes. On the other hand, the increased cation mobility considerably increases the sensitivity to the temperature of the electrolyte, which can change the growth mechanism of the oxide layer and thus its morphology.
{"title":"EFFECT OF A SCANDIUM ADDITION ON ANODIZING AlMg ALLOYS","authors":"B. Karpe, Katarina Kern, J. Kovač, M. Klanjšek Gunde, A. Nagode, M. Bizjak, M. Zorc","doi":"10.17222/mit.2023.755","DOIUrl":"https://doi.org/10.17222/mit.2023.755","url":null,"abstract":"Scandium (Sc) is known to be one of the most effective alloying elements of aluminum alloys. The only drawback is its high price, but that could change quickly due to the promising results of recent research on its extraction. However, the data on how it affects anodic oxidation are very scarce. In this research, we analyzed how a micro-addition of Sc to the AlMg alloy affects the growth mechanism and properties of the protective aluminium oxide layer depending on the anodization parameters. For comparison, alloy AA5083 with a similar magnesium content was also anodized with the same anodizing parameters. In all experiments, sulfuric acid (VI) with concentrations of 1.72 M or 2.2 M at temperatures of 21 °C or 35 °C was used as the electrolyte. Potentiostatic (18 V) and galvanostatic (20 mA/cm2) anodizing methods were applied. The results (SED-EDS) show that scandium is uniformly intercalated in the matrix of the oxide layer and decreases its resistivity, which increases the oxide growth rate during potentiostatic anodizing and decreases the pore density and pore diameters during galvanostatic anodizing. Moreover, it increases the mobility of cations through the oxide layer, thus accelerating the oxidation reaction in concentrated sulfuric acid electrolytes. On the other hand, the increased cation mobility considerably increases the sensitivity to the temperature of the electrolyte, which can change the growth mechanism of the oxide layer and thus its morphology.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"11 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72846552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Friction stir welding of AISI 304 stainless-steel sheets was successfully carried out with a tungsten-alloy (W+La2O3) tool and the effect of the tool rotational speed on the microstructure and mechanical properties of the joints were evaluated. 3-mm-thick plates were friction-stir welded at various rotational speeds of 600–1000 min–1 and a constant welding speed of 40 mm/min with a constant axial load of 15 kN. Defect-free joints were produced at 800 min–1 and 900 min–1, indicating a proper plastic flow of the material and ensuring adequate heat generation during welding. Tensile, Charpy impact, compression and microhardness tests were performed to evaluate the joint mechanical properties. The microstructural behavior of the welded and base-metal samples was examined with optical microscopy and scanning electron microscopy. According to the mechanical results, the welded material has a higher yield strength than the base metal due to the grain refinement and work hardening effect in the stir zone. FSW welds have a higher hardness than the base metal due to the high density of dislocations and continuous dynamic recrystallization. The joints also exhibit acceptable impact toughness. Finally, the EDS analysis confirms that there is no secondary-phase formation in the weld zone of the fabricated material.
{"title":"MECHANICAL AND METALLURGICAL PROPERTIES OF FRICTION-STIR-WELDED AISI 304 STAINLESS STEEL","authors":"Sundar raju Govindaraj, Sivakumar Karuppa","doi":"10.17222/mit.2022.678","DOIUrl":"https://doi.org/10.17222/mit.2022.678","url":null,"abstract":"Friction stir welding of AISI 304 stainless-steel sheets was successfully carried out with a tungsten-alloy (W+La2O3) tool and the effect of the tool rotational speed on the microstructure and mechanical properties of the joints were evaluated. 3-mm-thick plates were friction-stir welded at various rotational speeds of 600–1000 min–1 and a constant welding speed of 40 mm/min with a constant axial load of 15 kN. Defect-free joints were produced at 800 min–1 and 900 min–1, indicating a proper plastic flow of the material and ensuring adequate heat generation during welding. Tensile, Charpy impact, compression and microhardness tests were performed to evaluate the joint mechanical properties. The microstructural behavior of the welded and base-metal samples was examined with optical microscopy and scanning electron microscopy. According to the mechanical results, the welded material has a higher yield strength than the base metal due to the grain refinement and work hardening effect in the stir zone. FSW welds have a higher hardness than the base metal due to the high density of dislocations and continuous dynamic recrystallization. The joints also exhibit acceptable impact toughness. Finally, the EDS analysis confirms that there is no secondary-phase formation in the weld zone of the fabricated material.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"41 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81273118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Han Zhang, Tingting Zhang, J. Zhang, Zhihang Yan, Wen-xian Wang
The effect of reducing the thinning rate when flow forming AZ31B magnesium alloy barrels on the microstructure, crystal orientation, micro-, nano- and macro-mechanical properties was investigated. The results demonstrate that when the magnesium alloy undergoes different degrees of plastic deformation after flow forming, the grain size and dislocation density inside the crystal change greatly, and the evolution pattern of the organization has a significant effect on the mechanical properties of the materials. The stress-strain curve of the cylindrical parts was obtained by nano-indentation and hardness. This is important to improve the mechanical properties of the magnesium alloy.
{"title":"EFFECT OF THICKNESS REDUCTIONS ON MICROSTRUCTURE AND NANO-MECHANICAL PROPERTIES OF AZ31 MAGNESIUM ALLOY IN FLOW-FORMING","authors":"Han Zhang, Tingting Zhang, J. Zhang, Zhihang Yan, Wen-xian Wang","doi":"10.17222/mit.2022.659","DOIUrl":"https://doi.org/10.17222/mit.2022.659","url":null,"abstract":"The effect of reducing the thinning rate when flow forming AZ31B magnesium alloy barrels on the microstructure, crystal orientation, micro-, nano- and macro-mechanical properties was investigated. The results demonstrate that when the magnesium alloy undergoes different degrees of plastic deformation after flow forming, the grain size and dislocation density inside the crystal change greatly, and the evolution pattern of the organization has a significant effect on the mechanical properties of the materials. The stress-strain curve of the cylindrical parts was obtained by nano-indentation and hardness. This is important to improve the mechanical properties of the magnesium alloy.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79611387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aluminium metal matrix composites have wide applications in the aerospace and automotive industries due to their excellent physical properties like hardness, tensile strength, etc. The reinforcement of ZrO2 hard ceramic particles and soft solid lubricant graphite on AA6082 produces a high-strength composite. This research aims to fabricate AA6082-ZrO2-Gr MMCs with different compositions and evaluate the abrasive-waterjet-machining (AWJM) parameters in the machining of the fabricated composites, which eliminates the thermal distortion and damage to the work material. The experiments were conducted by varying the dominant process parameters such as water pressure, traverse speed, abrasive flow rate and mesh size. The kerf taper angle was affected by the traverse speed and water pressure, while the surface roughness was affected by the abrasive flow rate, mesh size and water pressure. The abrasive mesh size of 120 provided the best surface finish.
{"title":"INVESTIGATION OF THE SURFACE QUALITY OF AA6082-ZrO2-Gr MMCs USING ABRASIVE WATERJET MACHINING","authors":"Kannapiran Karuppasamy, B. Ranganathan","doi":"10.17222/mit.2022.602","DOIUrl":"https://doi.org/10.17222/mit.2022.602","url":null,"abstract":"Aluminium metal matrix composites have wide applications in the aerospace and automotive industries due to their excellent physical properties like hardness, tensile strength, etc. The reinforcement of ZrO2 hard ceramic particles and soft solid lubricant graphite on AA6082 produces a high-strength composite. This research aims to fabricate AA6082-ZrO2-Gr MMCs with different compositions and evaluate the abrasive-waterjet-machining (AWJM) parameters in the machining of the fabricated composites, which eliminates the thermal distortion and damage to the work material. The experiments were conducted by varying the dominant process parameters such as water pressure, traverse speed, abrasive flow rate and mesh size. The kerf taper angle was affected by the traverse speed and water pressure, while the surface roughness was affected by the abrasive flow rate, mesh size and water pressure. The abrasive mesh size of 120 provided the best surface finish.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"29 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73751294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research introduces an ultra-wideband frequency-selective surface (FSS) that offers a very good bandwidth for insulation and communication applications. It consists of two layers: a dielectric substrate layer and a metal layer. The basal layer, which is the substrate, is made of FR4; and the top patch, which is the metal, is made of copper. The FSS is constructed without using several layers or several resonators in a single unit cell. This single-sheet, planar-structure-based FSS has an ultra-level bandwidth of 20.3 GHz, ranging from 2.3 GHz to 22.6 GHz. It will be employed in microwave applications in the S, C, X, Ku, and K bands, with a centre frequency of 10.6 GHz. The polarisation and angle stability of the transverse electric (TE) and transverse magnetic (TM) modes are examined, and it was found that they are insensitive up to 90 degrees. Plots depicting the distribution of the magnetic field, surface current, and electric field are used to analyse the structure's physical mechanism. The performances from previous studies are compared and contrasted with that of the current work.
{"title":"A SINGLE-LAYER FSS FOR S-, C-, X-, KU- AND K-BAND APPLICATIONS","authors":"Srigitha Surendranath, Varalakshmi Subramanian, Arthi Devarani Paulretnam, Elakkiya Azhagar","doi":"10.17222/mit.2022.710","DOIUrl":"https://doi.org/10.17222/mit.2022.710","url":null,"abstract":"This research introduces an ultra-wideband frequency-selective surface (FSS) that offers a very good bandwidth for insulation and communication applications. It consists of two layers: a dielectric substrate layer and a metal layer. The basal layer, which is the substrate, is made of FR4; and the top patch, which is the metal, is made of copper. The FSS is constructed without using several layers or several resonators in a single unit cell. This single-sheet, planar-structure-based FSS has an ultra-level bandwidth of 20.3 GHz, ranging from 2.3 GHz to 22.6 GHz. It will be employed in microwave applications in the S, C, X, Ku, and K bands, with a centre frequency of 10.6 GHz. The polarisation and angle stability of the transverse electric (TE) and transverse magnetic (TM) modes are examined, and it was found that they are insensitive up to 90 degrees. Plots depicting the distribution of the magnetic field, surface current, and electric field are used to analyse the structure's physical mechanism. The performances from previous studies are compared and contrasted with that of the current work. \u0000 ","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"21 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87283426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ningning Li, Lei Xu, Liang Huang, Yuping Tong, Z. Jiang, Keliang Li
A functionally graded Ni-Al coating can improve the hardness of low-carbon steel, which can then adapt to various conditions due to a high hardness. The primary purpose of this research was the preparation of a Ni-Al coating by adopting a two-step method including nickel plating and pack aluminizing. The coating phase and morphology were characterized with XRD, SEM and EDS. Subsequently, the hardness of the Ni-Al coating was measured using a nanoindentation test. The results show that different aluminum contents in the coating surface lead to different coating phases, mainly Ni2Al3. The change in the coating phases conformed to the Ni-Al binary phase diagram. The Ni-Al coating showed a continuous gradient structure and composition. In addition, the coating also showed continuous gradient variation, relating to the hardness.
{"title":"PREPARATION AND HARDNESS OF A FUNCTIONALLY GRADED Ni-Al COATING","authors":"Ningning Li, Lei Xu, Liang Huang, Yuping Tong, Z. Jiang, Keliang Li","doi":"10.17222/mit.2022.650","DOIUrl":"https://doi.org/10.17222/mit.2022.650","url":null,"abstract":"A functionally graded Ni-Al coating can improve the hardness of low-carbon steel, which can then adapt to various conditions due to a high hardness. The primary purpose of this research was the preparation of a Ni-Al coating by adopting a two-step method including nickel plating and pack aluminizing. The coating phase and morphology were characterized with XRD, SEM and EDS. Subsequently, the hardness of the Ni-Al coating was measured using a nanoindentation test. The results show that different aluminum contents in the coating surface lead to different coating phases, mainly Ni2Al3. The change in the coating phases conformed to the Ni-Al binary phase diagram. The Ni-Al coating showed a continuous gradient structure and composition. In addition, the coating also showed continuous gradient variation, relating to the hardness. \u0000 ","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"316 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77575744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Palanivel, Soundararaja Perumal Vigneshwaran, Y. Alqurashi, M. A. Rasheed
The joining of aluminium (Al) and copper (Cu) is an essential spot weld for renewable energy applications due to its excellent thermal and electrical conductivity. It is challenging to produce a high-quality Al-Cu spot weld using traditional techniques and the durability of a weldment is also uncertain. A new welding technique that is effective and suitable for spot welding Cu and Al is friction-melt-bonding (FMB) spot welding. The process parameters employed during welding have a strong impact on the quality of a weld. The strategy for integrating the FMB process characteristics, such as tool rotational speed and dwell time, into a mathematical model that may be used for predicting the process parameters of dissimilar spot joints, was the focus of this study. The findings showed that the tensile shear fracture load (TSFL) was significantly influenced by the tool's rotational speed and dwell time. Optimization was carried out using the response surface methodology (RSM) to find the best FMB process parameters for making a dissimilar spot weld of AA 6061-Cu.
{"title":"EFFECTS OF PRE-OXIDATION ON HOT CORROSION RESISTANCE OF Al–Si COATINGS","authors":"R. Palanivel, Soundararaja Perumal Vigneshwaran, Y. Alqurashi, M. A. Rasheed","doi":"10.17222/mit.2022.689","DOIUrl":"https://doi.org/10.17222/mit.2022.689","url":null,"abstract":"The joining of aluminium (Al) and copper (Cu) is an essential spot weld for renewable energy applications due to its excellent thermal and electrical conductivity. It is challenging to produce a high-quality Al-Cu spot weld using traditional techniques and the durability of a weldment is also uncertain. A new welding technique that is effective and suitable for spot welding Cu and Al is friction-melt-bonding (FMB) spot welding. The process parameters employed during welding have a strong impact on the quality of a weld. The strategy for integrating the FMB process characteristics, such as tool rotational speed and dwell time, into a mathematical model that may be used for predicting the process parameters of dissimilar spot joints, was the focus of this study. The findings showed that the tensile shear fracture load (TSFL) was significantly influenced by the tool's rotational speed and dwell time. Optimization was carried out using the response surface methodology (RSM) to find the best FMB process parameters for making a dissimilar spot weld of AA 6061-Cu.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"27 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78122914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Pečlin, J. Rozman, Renata Janež, Nuša Bajželj, S. Ribaric, T. Mirkovic̆
The principal objective of the research was to develop and test a multichannel system intended to capture heart (PCG) and Korotkoff sound (KS) signals in a human model of transcutaneous auricular nerve stimulation (tANS). In particular, the purpose was to develop contact auscultation transducers (transducers) capable of capturing PCG and KS at standard auscultation positions without and during the selective tANS. The scope was to develop transducers capable of capturing body sounds lying in a portion of the frequency spectrum between 20 Hz and 200 Hz. They should be as insensitive as possible to external sound or ambient noise and should be capable of compensating for friction noise due to body movements. The system developed consisted of five transducers, where four of them were intended for the auscultation of PCG generated by heart valves, while one of them was intended to capture KS. The functionality of the transducers was tested in the female model by applying four of transducers to the standard positions on the chest and one over the Brachial artery. The results show that the system developed was highly sensitive to PCG and KS, and less sensitive to external ambient sounds and friction noise. Namely, the S1 and S2 heart-sound peaks are present clearly in the recorded PCG signal as well as during the tANS. It was also shown that during the tANS, heart cycles became slightly shorter and, thus, the heart rhythm slightly higher. Finally, during the tANS, both heart sounds S1 and S2 became louder. In conclusion, the findings provide some evidence that the sounds captured by the transducers emanate from the organs under study and are related to their activity and tANS.
{"title":"AUSCULTATION OF A HEART AND VASCULAR ACTIVITY DURING AURICULAR NERVE STIMULATION","authors":"P. Pečlin, J. Rozman, Renata Janež, Nuša Bajželj, S. Ribaric, T. Mirkovic̆","doi":"10.17222/mit.2022.700","DOIUrl":"https://doi.org/10.17222/mit.2022.700","url":null,"abstract":"The principal objective of the research was to develop and test a multichannel system intended to capture heart (PCG) and Korotkoff sound (KS) signals in a human model of transcutaneous auricular nerve stimulation (tANS). In particular, the purpose was to develop contact auscultation transducers (transducers) capable of capturing PCG and KS at standard auscultation positions without and during the selective tANS. The scope was to develop transducers capable of capturing body sounds lying in a portion of the frequency spectrum between 20 Hz and 200 Hz. They should be as insensitive as possible to external sound or ambient noise and should be capable of compensating for friction noise due to body movements. The system developed consisted of five transducers, where four of them were intended for the auscultation of PCG generated by heart valves, while one of them was intended to capture KS. The functionality of the transducers was tested in the female model by applying four of transducers to the standard positions on the chest and one over the Brachial artery. The results show that the system developed was highly sensitive to PCG and KS, and less sensitive to external ambient sounds and friction noise. Namely, the S1 and S2 heart-sound peaks are present clearly in the recorded PCG signal as well as during the tANS. It was also shown that during the tANS, heart cycles became slightly shorter and, thus, the heart rhythm slightly higher. Finally, during the tANS, both heart sounds S1 and S2 became louder. In conclusion, the findings provide some evidence that the sounds captured by the transducers emanate from the organs under study and are related to their activity and tANS.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"105 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86965718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of the present research is to assess the impact of foundry sand (FS) and cement kiln dust (CKD) on the autogenous shrinkage, drying and total shrinkage of engineered cementitious composites (ECCs) over 100 d. Additionally, the pore sizes and their distribution in the developed ECC system were assessed through the BJH adsorption technique. The findings showed that the pore structure was refined continuously over time. This indicates that the CKD-modified ECC mixes demonstrated decreased autogenous shrinkage at the early and later ages of the 100-d period, although the total shrinkage, developed during the later stages, was comparable to the CKD/FS mixes and conventional ECCs. Specimens with 30 % FS and 15 % CKD inclusions showed significantly fewer medium capillary holes and more gel pores. As the pores in a CKD-modified ECC system are smaller than in the traditional ECC, the modified ECC specimens are denser and show a lower loss of water.
{"title":"SHRINKAGE BEHAVIOR OF AN ECO-FRIENDLY ENGINEERED CEMENTITIOUS COMPOSITE","authors":"R. R. Infanto, S. A. Kumar","doi":"10.17222/mit.2022.669","DOIUrl":"https://doi.org/10.17222/mit.2022.669","url":null,"abstract":"The purpose of the present research is to assess the impact of foundry sand (FS) and cement kiln dust (CKD) on the autogenous shrinkage, drying and total shrinkage of engineered cementitious composites (ECCs) over 100 d. Additionally, the pore sizes and their distribution in the developed ECC system were assessed through the BJH adsorption technique. The findings showed that the pore structure was refined continuously over time. This indicates that the CKD-modified ECC mixes demonstrated decreased autogenous shrinkage at the early and later ages of the 100-d period, although the total shrinkage, developed during the later stages, was comparable to the CKD/FS mixes and conventional ECCs. Specimens with 30 % FS and 15 % CKD inclusions showed significantly fewer medium capillary holes and more gel pores. As the pores in a CKD-modified ECC system are smaller than in the traditional ECC, the modified ECC specimens are denser and show a lower loss of water.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"13 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73167020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Environmental concerns, such as pollution, greenhouse-gas emissions, sustainability, global warming and climate change, are the biggest challenges of our times. In this respect, the more efficient use of energy and materials combined with technology optimization and innovation are playing a key role in the quest to become a green society with green industry. Multiple environmental and economic benefits can mostly be achieved through novel, lightweight energy-efficient designs. In order to develop and properly use new materials and new designs, complete understanding and information on their properties must be obtained. It is also vital to know how these properties are affected by the conditions of a specific application. Furthermore, as the design of components is pushed towards the limits, unsuitable and outdated measuring methods, measuring uncertainty and deviations from the defined material properties can lead to unexpected premature failure of the component and environmental problems. For the green future, it is extremely important to develop new, advanced materials. However, it is often the changes of the production technology and to the surface of an already-existing material that can achieve great benefits to performance as well as the environment. It is all about modifying the material to perform better, last longer, be biocompatible and achieve different functionalities. Finally, besides high-tech equipment and research facilities, close cooperation between universities, research institutes and industry is needed to develop technologies, functional materials and solutions that can effectively support the journey of our society into a green future
{"title":"ADVANCED MATERIALS AND RESEARCH FOR THE GREEN FUTURE","authors":"B. Podgornik","doi":"10.17222/mit.2022.717","DOIUrl":"https://doi.org/10.17222/mit.2022.717","url":null,"abstract":"Environmental concerns, such as pollution, greenhouse-gas emissions, sustainability, global warming and climate change, are the biggest challenges of our times. In this respect, the more efficient use of energy and materials combined with technology optimization and innovation are playing a key role in the quest to become a green society with green industry. Multiple environmental and economic benefits can mostly be achieved through novel, lightweight energy-efficient designs. In order to develop and properly use new materials and new designs, complete understanding and information on their properties must be obtained. It is also vital to know how these properties are affected by the conditions of a specific application. Furthermore, as the design of components is pushed towards the limits, unsuitable and outdated measuring methods, measuring uncertainty and deviations from the defined material properties can lead to unexpected premature failure of the component and environmental problems. \u0000For the green future, it is extremely important to develop new, advanced materials. However, it is often the changes of the production technology and to the surface of an already-existing material that can achieve great benefits to performance as well as the environment. It is all about modifying the material to perform better, last longer, be biocompatible and achieve different functionalities. Finally, besides high-tech equipment and research facilities, close cooperation between universities, research institutes and industry is needed to develop technologies, functional materials and solutions that can effectively support the journey of our society into a green future","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"29 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81384075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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