The powder of hematite sample was isothermally reduced with hydrogen-water vapor gas mixture at 1023K-1273K. The results indicated that the overall reduction process of hematite could be separated into three stages (Fe2O3-Fe3O4-FeO-Fe) to respectively study. At 1023K, the average reaction rate dropped by 53.6% in the stage 1 when the water vapor content of gas reactant rose from 0% to 50%, and it decreased by about 77.2% in the stage 2. However, in the stage 3, when the water vapor content only increased from 0% to 20%, it decreased by about 78.1%. Besides, the average reaction rate had a roughly negative linear relationship with the water vapor content, and the results further shown that the effect of water vapor on the reduction reaction increased with increasing reaction temperature at all stages of the reduction reaction. The microstructure of reduction products showed that it still had some holes, which the channel for hydrogen diffusion was not seriously blocked. In order to further clarify the influence of water vapor in the reduction stage, different models were considered, and the range of apparent activation energy of different stages obtained by model fitting was about 20-70 kJ/mol, which also confirmed the absence of solid-state diffusion phenomenon.
{"title":"Effect of water vapor on the reduction kinetics of hematite powder by hydrogen-water vapor in different stages","authors":"X. Mao, X. Hu, Yuewen Fan, K. Chou","doi":"10.2298/jmmb220523006m","DOIUrl":"https://doi.org/10.2298/jmmb220523006m","url":null,"abstract":"The powder of hematite sample was isothermally reduced with hydrogen-water vapor gas mixture at 1023K-1273K. The results indicated that the overall reduction process of hematite could be separated into three stages (Fe2O3-Fe3O4-FeO-Fe) to respectively study. At 1023K, the average reaction rate dropped by 53.6% in the stage 1 when the water vapor content of gas reactant rose from 0% to 50%, and it decreased by about 77.2% in the stage 2. However, in the stage 3, when the water vapor content only increased from 0% to 20%, it decreased by about 78.1%. Besides, the average reaction rate had a roughly negative linear relationship with the water vapor content, and the results further shown that the effect of water vapor on the reduction reaction increased with increasing reaction temperature at all stages of the reduction reaction. The microstructure of reduction products showed that it still had some holes, which the channel for hydrogen diffusion was not seriously blocked. In order to further clarify the influence of water vapor in the reduction stage, different models were considered, and the range of apparent activation energy of different stages obtained by model fitting was about 20-70 kJ/mol, which also confirmed the absence of solid-state diffusion phenomenon.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"25 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83605623","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}
Yun-yang Xiao, L.-J. Wang, S.-Y. Liu, Xiao-bo He, K. Chou
Direct alloying of chromium by chromite attracts a lot of interest for its superiority in energy-saving and process simplification. The knowledge of chromium alloying by reduction of FeCr2O4, the main component of chromite, is key to understanding the mechanism of chromium alloying from chromite. The effect of melt composition (carbon and chromium addition) and temperature on the reduction of FeCr2O4 by carbon-containing iron melt was studied. The higher the carbon content is in the melt, the higher chromium recovery is obtained. Similarly, the higher temperature is favourable for the reduction of FeCr2O4. The reduction of FeCr2O4 was impeded by chromium addition due to the lower activity of carbon resulting from the strong attraction between carbon and chromium. The kinetics of FeCr2O4 reduction by carbon dissolving in iron melt were investigated, and the results indicated that the controlling step is the chemical reaction at the FeCr2O4/melt interface at 1823K. And the calculated activation energy for the chemical reaction is 392.82 kJ/mol.
{"title":"Kinetic mechanism of FeCr2O4 reduction in carbon-containing iron melt","authors":"Yun-yang Xiao, L.-J. Wang, S.-Y. Liu, Xiao-bo He, K. Chou","doi":"10.2298/jmmb230215010x","DOIUrl":"https://doi.org/10.2298/jmmb230215010x","url":null,"abstract":"Direct alloying of chromium by chromite attracts a lot of interest for its superiority in energy-saving and process simplification. The knowledge of chromium alloying by reduction of FeCr2O4, the main component of chromite, is key to understanding the mechanism of chromium alloying from chromite. The effect of melt composition (carbon and chromium addition) and temperature on the reduction of FeCr2O4 by carbon-containing iron melt was studied. The higher the carbon content is in the melt, the higher chromium recovery is obtained. Similarly, the higher temperature is favourable for the reduction of FeCr2O4. The reduction of FeCr2O4 was impeded by chromium addition due to the lower activity of carbon resulting from the strong attraction between carbon and chromium. The kinetics of FeCr2O4 reduction by carbon dissolving in iron melt were investigated, and the results indicated that the controlling step is the chemical reaction at the FeCr2O4/melt interface at 1823K. And the calculated activation energy for the chemical reaction is 392.82 kJ/mol.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"22 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88402785","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}
Chromium-molybdenum steel (16Mo3) is widely used in petroleum, gas, automotive, and construction industries due to its good oxidation resistance and mechanical properties at moderately elevated temperatures. The aim of the research was to evaluate the corrosion susceptibility of 16Mo3 steel in hot rolled and aluminized states. Aluminization was performed by diffusion pack aluminization process at 900?C/2h and 730?C/4h, respectively. Electrochemical corrosion testing included measuring open circuit potential (EOCP), linear polarization resistance (LPR), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in potassium phosphate buffer (KH2PO4, pH = 7). Optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) have been used for surface layer microstructure characterization before and after corrosion tests. It has been demonstrated that corrosion resistance of aluminized steel is increased substantially. Corrosion properties are related to the structure and properties of intermetallic phase (FeAl, FeAl2 and Fe2Al5) formed on the surface of 16Mo3 steel.
铬钼钢(16Mo3)具有良好的抗氧化性能和中等高温下的机械性能，广泛应用于石油、天然气、汽车和建筑行业。研究了16Mo3钢在热轧和渗铝状态下的腐蚀敏感性。采用900℃的扩散包渗铝工艺进行渗铝。C/2h和730?分别为4 C / h。电化学腐蚀测试包括测量磷酸钾缓冲液(KH2PO4, pH = 7)的开路电位(EOCP)、线性极化电阻(LPR)、动电位极化和电化学阻抗谱(EIS)。腐蚀测试前后采用光学显微镜(OM)、扫描电镜(SEM)和能量色散x射线能谱(EDS)对表层微观结构进行表征。结果表明，渗铝钢的耐蚀性大大提高。腐蚀性能与16Mo3钢表面形成的金属间相(FeAl、FeAl2和Fe2Al5)的结构和性能有关。
{"title":"Corrosion properties of aluminized 16Mo3 steel","authors":"B. Karpe, K. Prijatelj, M. Bizjak, T. Kosec","doi":"10.2298/jmmb220927008k","DOIUrl":"https://doi.org/10.2298/jmmb220927008k","url":null,"abstract":"Chromium-molybdenum steel (16Mo3) is widely used in petroleum, gas, automotive, and construction industries due to its good oxidation resistance and mechanical properties at moderately elevated temperatures. The aim of the research was to evaluate the corrosion susceptibility of 16Mo3 steel in hot rolled and aluminized states. Aluminization was performed by diffusion pack aluminization process at 900?C/2h and 730?C/4h, respectively. Electrochemical corrosion testing included measuring open circuit potential (EOCP), linear polarization resistance (LPR), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in potassium phosphate buffer (KH2PO4, pH = 7). Optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) have been used for surface layer microstructure characterization before and after corrosion tests. It has been demonstrated that corrosion resistance of aluminized steel is increased substantially. Corrosion properties are related to the structure and properties of intermetallic phase (FeAl, FeAl2 and Fe2Al5) formed on the surface of 16Mo3 steel.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"417 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79470913","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}
Hai-yan Zheng, Y. Zhang, Z. Wang, Jingbo Du, X. Jiang, Qiang-jian Gao, Feng-man Shen
With a view to understanding the performance of the blast furnace slag with high Al2O3 content, the effects of w(MgO)/w(Al2O3), w(CaO)/w(SiO2), and w(Al2O3) on the melting performance (melting characteristic temperature and melting heat) of the blast furnace slag with high Al2O3 content were investigated by the differential scanning calorimeter (DSC) method. Experimental results indicate that melting end temperature (Tend) for almost all the slags has no obvious change with the increase of w(MgO)/w(Al2O3), w(CaO)/w(SiO2) and w(Al2O3) of the slag will raise Tend of the slag. When (w(MgO)/w(Al2O3), R, and w(Al2O3) are high, the melting onset temperature (Tonset) of the slag increases with the increase of any variables. When w(CaO)/w(SiO2) is low, Tonset of the slag decreases with the increase of w(Al2O3). w(MgO)/w(Al2O3), w(CaO)/w(SiO2), and w(Al2O3) within the scope of this study and all these factors lead to the increase of the slag melting heat.
{"title":"The melting performance of high alumina blast furnace slags","authors":"Hai-yan Zheng, Y. Zhang, Z. Wang, Jingbo Du, X. Jiang, Qiang-jian Gao, Feng-man Shen","doi":"10.2298/jmmb220722009z","DOIUrl":"https://doi.org/10.2298/jmmb220722009z","url":null,"abstract":"With a view to understanding the performance of the blast furnace slag with high Al2O3 content, the effects of w(MgO)/w(Al2O3), w(CaO)/w(SiO2), and w(Al2O3) on the melting performance (melting characteristic temperature and melting heat) of the blast furnace slag with high Al2O3 content were investigated by the differential scanning calorimeter (DSC) method. Experimental results indicate that melting end temperature (Tend) for almost all the slags has no obvious change with the increase of w(MgO)/w(Al2O3), w(CaO)/w(SiO2) and w(Al2O3) of the slag will raise Tend of the slag. When (w(MgO)/w(Al2O3), R, and w(Al2O3) are high, the melting onset temperature (Tonset) of the slag increases with the increase of any variables. When w(CaO)/w(SiO2) is low, Tonset of the slag decreases with the increase of w(Al2O3). w(MgO)/w(Al2O3), w(CaO)/w(SiO2), and w(Al2O3) within the scope of this study and all these factors lead to the increase of the slag melting heat.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"43 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73786512","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}
Huiyuan Xie, Z. Yang, Q. Ma, W. Meng, L. Hu, X. Yin
In this work, the effect of extrusion process on the mechanical properties and the stress corrosion cracking (SCC) resistance of 7N01 aluminum alloys are systematically investigated by tensile testing, slow strain rate testing(SSRT), electrochemical experiment, scanning electron microscopy(SEM), electron backscattered diffraction (EBSD) and transmission electron microscope (TEM) observation, respectively. The results show that with the increase of extrusion temperature, the SCC resistances of the alloys deteriorate, and this tendency is also proved by the electrochemical experiments include polarization curves and EIS results. The Microstructure observation results reveal that recrystallization play an important role on the SCC resistances of the alloys: the new recrystallization grain boundaries with higher grain boundary energy and wider PFZ can magnify the difference of electrochemical property between grain boundary area and the grain interior, thus raises the stress corrosion crack sensitivity of the alloys.
{"title":"Effect of extrusion process on the stress corrosion cracking resistance of 7N01 aluminum alloy","authors":"Huiyuan Xie, Z. Yang, Q. Ma, W. Meng, L. Hu, X. Yin","doi":"10.2298/jmmb221229012x","DOIUrl":"https://doi.org/10.2298/jmmb221229012x","url":null,"abstract":"In this work, the effect of extrusion process on the mechanical properties and the stress corrosion cracking (SCC) resistance of 7N01 aluminum alloys are systematically investigated by tensile testing, slow strain rate testing(SSRT), electrochemical experiment, scanning electron microscopy(SEM), electron backscattered diffraction (EBSD) and transmission electron microscope (TEM) observation, respectively. The results show that with the increase of extrusion temperature, the SCC resistances of the alloys deteriorate, and this tendency is also proved by the electrochemical experiments include polarization curves and EIS results. The Microstructure observation results reveal that recrystallization play an important role on the SCC resistances of the alloys: the new recrystallization grain boundaries with higher grain boundary energy and wider PFZ can magnify the difference of electrochemical property between grain boundary area and the grain interior, thus raises the stress corrosion crack sensitivity of the alloys.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"31 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78195822","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}
B. Wen, X.-P. Zhang, D.-L. Liu, J.-X. Li, X.-D. Sun, J.-L. Yang
Ultrafine iron ore concentrate pose challenges like poor pellets formation performance, low-bursting temperature, and a complex drying thermal regime. To examine the drying characteristics of green pellets of ultrafine iron ore concentrate, we employed Weibull distribution function and Dincer model to fit and analyze the corresponding drying curve. The effects of drying temperature and air speed on the strength of dried pellets were also studied. Our findings reveal that the drying process of green pellets of ultrafine iron ore concentrate involves three stages: ascending speed, constant speed, and descending speed. As the drying temperature and air speed increase, the drying time decreases. The coefficient of determination R2 for the fitted Weibull distribution function model ranged from 0.995 to 0.998, while the R2 value for the Dincer model ranged from 0.990 to 0.996. Both fitted models align with experimental data and prove to be effective. According to the Bi values obtained through the Dincer model, raising the drying air speed in the initial stage and the drying air temperature in the subsequent stage of the drying system can efficiently remove moisture, reduce green pellets rupture risk, and maintain productivity. The moisture diffusion coefficient and convective mass transfer coefficient increase with rising temperature and air velocity, following the order of Deff > Dcal > D*eff as determined by the Weibull distribution function, Dincer model, and Fick's second law. Additionally, the activation energy value of ultrafine iron ore concentrate for drying derived from the Arrhenius formula is 4515.60 J/(mol?K). Notably, increasing drying temperature increases the strength of dried particles due to their more compact and dense internal structure. This study offers theoretical support for simulating the drying of green ultrafine iron ore concentrate pellets and provides guidelines for selecting diverse drying conditions and designing drying equipment.
{"title":"Study on the drying characteristics of green pellets of ultrafine iron ore concentrate","authors":"B. Wen, X.-P. Zhang, D.-L. Liu, J.-X. Li, X.-D. Sun, J.-L. Yang","doi":"10.2298/jmmb220810018w","DOIUrl":"https://doi.org/10.2298/jmmb220810018w","url":null,"abstract":"Ultrafine iron ore concentrate pose challenges like poor pellets formation performance, low-bursting temperature, and a complex drying thermal regime. To examine the drying characteristics of green pellets of ultrafine iron ore concentrate, we employed Weibull distribution function and Dincer model to fit and analyze the corresponding drying curve. The effects of drying temperature and air speed on the strength of dried pellets were also studied. Our findings reveal that the drying process of green pellets of ultrafine iron ore concentrate involves three stages: ascending speed, constant speed, and descending speed. As the drying temperature and air speed increase, the drying time decreases. The coefficient of determination R2 for the fitted Weibull distribution function model ranged from 0.995 to 0.998, while the R2 value for the Dincer model ranged from 0.990 to 0.996. Both fitted models align with experimental data and prove to be effective. According to the Bi values obtained through the Dincer model, raising the drying air speed in the initial stage and the drying air temperature in the subsequent stage of the drying system can efficiently remove moisture, reduce green pellets rupture risk, and maintain productivity. The moisture diffusion coefficient and convective mass transfer coefficient increase with rising temperature and air velocity, following the order of Deff > Dcal > D*eff as determined by the Weibull distribution function, Dincer model, and Fick's second law. Additionally, the activation energy value of ultrafine iron ore concentrate for drying derived from the Arrhenius formula is 4515.60 J/(mol?K). Notably, increasing drying temperature increases the strength of dried particles due to their more compact and dense internal structure. This study offers theoretical support for simulating the drying of green ultrafine iron ore concentrate pellets and provides guidelines for selecting diverse drying conditions and designing drying equipment.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"26 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77572344","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}
A. Dębski, W. Gasior, W. Gierlotka, A. Baran, M. Polański
A drop calorimetry method was used to measure the partial and integral mixing enthalpies of Ag-Mg-Pd liquid solutions. The experiments were performed for six separate series of liquid alloys starting from the binary alloys with constant xAg/xMg ratios equal to 1/9, 1/3, 1/1, and 3/1 for (Ag0.10Mg0.90)1-xPdx and (Ag0.25Mg0.75)1-xPdx at 1116 K and (Ag0.50Mg0.50)1-xPdx and (Ag0.75Mg0.25)1-xPdx at 1279 K and xMg/xPd ratios of 9/1 and 8/1 for (Mg0.90Pd0.10)1-xAgx and (Mg0.80Pd0.20)1-xAgx at 1116 K. Then, using the thermodynamic properties of the binary systems in the form of the Redlich-Kister equations and the changes in mixing enthalpies provided by this study, the ternary interaction parameters were determined with the Muggianu model and our own software (TerGexHm). Based on the binary and ternary interaction parameters, the partial mixing enthalpies of Ag, Mg, and Pd were calculated for the same cross-sections where the measurements were conducted. These studies were the first step of an investigation of the Ag-Mg-Pd system before the calculation of the phase diagram for this ternary system.
{"title":"The magnesium-palladium-silver system: Thermodynamic properties of the liquid phase","authors":"A. Dębski, W. Gasior, W. Gierlotka, A. Baran, M. Polański","doi":"10.2298/jmmb230222016d","DOIUrl":"https://doi.org/10.2298/jmmb230222016d","url":null,"abstract":"A drop calorimetry method was used to measure the partial and integral mixing enthalpies of Ag-Mg-Pd liquid solutions. The experiments were performed for six separate series of liquid alloys starting from the binary alloys with constant xAg/xMg ratios equal to 1/9, 1/3, 1/1, and 3/1 for (Ag0.10Mg0.90)1-xPdx and (Ag0.25Mg0.75)1-xPdx at 1116 K and (Ag0.50Mg0.50)1-xPdx and (Ag0.75Mg0.25)1-xPdx at 1279 K and xMg/xPd ratios of 9/1 and 8/1 for (Mg0.90Pd0.10)1-xAgx and (Mg0.80Pd0.20)1-xAgx at 1116 K. Then, using the thermodynamic properties of the binary systems in the form of the Redlich-Kister equations and the changes in mixing enthalpies provided by this study, the ternary interaction parameters were determined with the Muggianu model and our own software (TerGexHm). Based on the binary and ternary interaction parameters, the partial mixing enthalpies of Ag, Mg, and Pd were calculated for the same cross-sections where the measurements were conducted. These studies were the first step of an investigation of the Ag-Mg-Pd system before the calculation of the phase diagram for this ternary system.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"75 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85475544","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}
B. Grzegorczyk, S. Rusz, P. Snopiński, O. Hilšer, A. Skowronek, A. Grajcar
The study concerns the influence of various variants of severe plastic deformation in the Equal Channel Angular Pressing (ECAP) process on the microstructure, microhardness and conductivity of the CuCoNi alloy. The evolution of the microstructure was investigated by microscopic observations and electron back-scattered diffraction (EBSD) in a scanning electron microscope (SEM). Using the Vickers method, tests of microhardness of samples were performed after various variants of the ECAP process. The conductivity was measured with an eddy current device for measuring electrical conductivity based on the complex impedance of the measuring probe. The results indicated the possibility of deformation of CuCoNi alloys in the process of pressing through the ECAP angular channel and developing their microstructure and properties. The method is an effective tool for strengthening the tested copper alloy by refinement of the microstructure. After the first pass, the grain size was reduced by 80%. Increasing the plastic deformation temperature did not significantly affect the obtained level of microstructure fragmentation - the average grain size is approx. 1.4-1.5 ?m. The fragmentation of the microstructure had a negligible effect on the conductivity of the CuCoNi alloy, which after the ECAP process oscillated at the value of 13 MS/m.
{"title":"Effect of ECAP process on deformability, microstructure and conductivity of CuCoNi alloy","authors":"B. Grzegorczyk, S. Rusz, P. Snopiński, O. Hilšer, A. Skowronek, A. Grajcar","doi":"10.2298/jmmb220309004g","DOIUrl":"https://doi.org/10.2298/jmmb220309004g","url":null,"abstract":"The study concerns the influence of various variants of severe plastic deformation in the Equal Channel Angular Pressing (ECAP) process on the microstructure, microhardness and conductivity of the CuCoNi alloy. The evolution of the microstructure was investigated by microscopic observations and electron back-scattered diffraction (EBSD) in a scanning electron microscope (SEM). Using the Vickers method, tests of microhardness of samples were performed after various variants of the ECAP process. The conductivity was measured with an eddy current device for measuring electrical conductivity based on the complex impedance of the measuring probe. The results indicated the possibility of deformation of CuCoNi alloys in the process of pressing through the ECAP angular channel and developing their microstructure and properties. The method is an effective tool for strengthening the tested copper alloy by refinement of the microstructure. After the first pass, the grain size was reduced by 80%. Increasing the plastic deformation temperature did not significantly affect the obtained level of microstructure fragmentation - the average grain size is approx. 1.4-1.5 ?m. The fragmentation of the microstructure had a negligible effect on the conductivity of the CuCoNi alloy, which after the ECAP process oscillated at the value of 13 MS/m.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"3 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90732838","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}
H. Allasi, P. Kumaradhas, M. Sivapragash, S. Vettivel
The as received AZ91D Mg alloy was coated by ZrO2 and ZrN ceramic using Physical Vapour Deposition (PVD) process. The dry sliding wear studies were carried out in a pin-on-disc wear tester at a sliding speed of 2-8 m/s and in normal loads of 2- 10 N. The wear mechanism such as abrasive, delamination, thermal softening and oxidation were observed. The results showed that the PVD coating increased the wear resistance of the AZ91D Mg alloy. The worn out surface were examined by using Scanning Electron Microscope (SEM).
{"title":"Study on wear behaviour characteristics of ZrO2 and ZrN coated AZ91D Mg alloy","authors":"H. Allasi, P. Kumaradhas, M. Sivapragash, S. Vettivel","doi":"10.2298/jmmb230323024a","DOIUrl":"https://doi.org/10.2298/jmmb230323024a","url":null,"abstract":"The as received AZ91D Mg alloy was coated by ZrO2 and ZrN ceramic using Physical Vapour Deposition (PVD) process. The dry sliding wear studies were carried out in a pin-on-disc wear tester at a sliding speed of 2-8 m/s and in normal loads of 2- 10 N. The wear mechanism such as abrasive, delamination, thermal softening and oxidation were observed. The results showed that the PVD coating increased the wear resistance of the AZ91D Mg alloy. The worn out surface were examined by using Scanning Electron Microscope (SEM).","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"26 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83262624","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}
Effect of thermal ageing (873 K/5000 h) on microstructure, tensile-plastic flow and work hardening parameters of normalized and tempered (N&T) 1.4W-0.06Ta Indian Reduced Activated Ferritic Martensitic (INRAFM) steel was investigated. Hollomon, Ludwigson and Voce equations were used to explain the tensile-plastic flow response of the INRAFM steel over a wide temperature range of 300-873 K. Variations of strain hardening exponent was found to increase on ageing due to increase in work hardening capability of aged steel while strain hardening coefficient decreased on ageing. TEM specimens extracted near the tensile tested specimen of different temperatures were used to correlate the formation and movement of dislocation debris structure of both N&T and thermal aged specimens. Tensile plastic flow behavior at different temperatures was appropriately represented by Hollomon. Ludwigson and Voce equations and best fitting was adjudged by the goodness of fit (i.e. lowest ?2 values). Both yield strength (YS) and ultimate tensile strength (UTS) were fitted by the initial stress and saturation stress respectively as per the Voce constitutive equation and variations of initial stress and saturation stress with temperature were observed for N&T and aged steel. The absolute value of Voce strain component (nv) decreases due to ageing exhibiting two-stage behaviour with increase in temperature. The acceleration of recovery process was found lower at high temperature in case of steel subjected to thermal ageing as compared to N&T steel. Voce relation has been successfully used to predict the yield stress (YS) and ultimate tensile strength (UTS) of both thermal aged and N&T IN-RAFM steel at different temperatures.
{"title":"Effect of thermal ageing on tensile-plastic flow and work hardening parameters of Indian reduced activated Ferritic Martensitic steel","authors":"K. C. Sahoo, K. Laha","doi":"10.2298/jmmb221114019s","DOIUrl":"https://doi.org/10.2298/jmmb221114019s","url":null,"abstract":"Effect of thermal ageing (873 K/5000 h) on microstructure, tensile-plastic flow and work hardening parameters of normalized and tempered (N&T) 1.4W-0.06Ta Indian Reduced Activated Ferritic Martensitic (INRAFM) steel was investigated. Hollomon, Ludwigson and Voce equations were used to explain the tensile-plastic flow response of the INRAFM steel over a wide temperature range of 300-873 K. Variations of strain hardening exponent was found to increase on ageing due to increase in work hardening capability of aged steel while strain hardening coefficient decreased on ageing. TEM specimens extracted near the tensile tested specimen of different temperatures were used to correlate the formation and movement of dislocation debris structure of both N&T and thermal aged specimens. Tensile plastic flow behavior at different temperatures was appropriately represented by Hollomon. Ludwigson and Voce equations and best fitting was adjudged by the goodness of fit (i.e. lowest ?2 values). Both yield strength (YS) and ultimate tensile strength (UTS) were fitted by the initial stress and saturation stress respectively as per the Voce constitutive equation and variations of initial stress and saturation stress with temperature were observed for N&T and aged steel. The absolute value of Voce strain component (nv) decreases due to ageing exhibiting two-stage behaviour with increase in temperature. The acceleration of recovery process was found lower at high temperature in case of steel subjected to thermal ageing as compared to N&T steel. Voce relation has been successfully used to predict the yield stress (YS) and ultimate tensile strength (UTS) of both thermal aged and N&T IN-RAFM steel at different temperatures.","PeriodicalId":51090,"journal":{"name":"Journal of Mining and Metallurgy Section B-Metallurgy","volume":"51 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78295860","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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