This paper aims to reveal the influence of different TiC powder particle sizes and process parameters on the cladding morphology of composite materials and realize the forming control of cladding layer. The center composite design of response surface method was adopted to analyze the effects of laser power, scanning speed and particle size on the cladding morphology of composite materials. The mathematical models between process parameters, TiC powder particle size and micro-hardness, wear volume of the composite cladding layer were established and confirmed by variance analysis and model verification. The results indicate that powder particle size has most significant effect on the micro-hardness, and it increase with the increase of scanning speed, laser power and powder particle size; the effect of powder particle size on the wear resistance of the clad layer is most significant, and it increases with the increase of powder particle size and decreases with the increase of scanning speed and laser power. The optimization of process parameters is carried out with the target of maximizing micro-hardness and minimizing wear area. The error rates between prediction and experiment for the micro-hardness and wear area are 0.1% and 2.0% respectively. The results of this paper provide a reference for the prediction and control of the cladding morphology of composite materials.
{"title":"Investigation on the effect of powder size on the properties of cladding layer based on RSM","authors":"Kun Yue, G. Lian, Meiyan Feng, Youji Zhan","doi":"10.1051/metal/2022003","DOIUrl":"https://doi.org/10.1051/metal/2022003","url":null,"abstract":"This paper aims to reveal the influence of different TiC powder particle sizes and process parameters on the cladding morphology of composite materials and realize the forming control of cladding layer. The center composite design of response surface method was adopted to analyze the effects of laser power, scanning speed and particle size on the cladding morphology of composite materials. The mathematical models between process parameters, TiC powder particle size and micro-hardness, wear volume of the composite cladding layer were established and confirmed by variance analysis and model verification. The results indicate that powder particle size has most significant effect on the micro-hardness, and it increase with the increase of scanning speed, laser power and powder particle size; the effect of powder particle size on the wear resistance of the clad layer is most significant, and it increases with the increase of powder particle size and decreases with the increase of scanning speed and laser power. The optimization of process parameters is carried out with the target of maximizing micro-hardness and minimizing wear area. The error rates between prediction and experiment for the micro-hardness and wear area are 0.1% and 2.0% respectively. The results of this paper provide a reference for the prediction and control of the cladding morphology of composite materials.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"18 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84712649","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}
In order to match rapidly development of high strength low alloy steels, the new metal cored wire contained copper was designed. The multi-pass weld metals were obtained by gas metal arc welding. Results show that microstructure of weld metals is bainite with M-A constituents, and there are nano-9RCu precipitates after PWHT. The weld metal as welded achieves 737 MPa of yield strength (YS) and 1097 MPa of ultimate tensile strength (UTS), with an elongation 8%. After PWHT, the YS and UTS are 725 MPa and 968 MPa, respectively, and elongation increases to 16%. The lower dislocations density and reduction of Cu element at solid solution state hence for the decrease of YS. As well, the nano-Cu precipitates and reduction of effective grain size make it increase. The combined effect of these factors makes YS decrease by only 12 MPa after PWHT. Besides, a good impact performance (46.6 J) can be obtained after PWHT, while it is only 27.7 J of weld metals as welded. The improved toughness of weld metals after PWHT is obtained by the contributions of finer effective grain size, soft bainite, and dispersed nano-9RCu precipitation. The nano-Cu precipitates can improve strength without damage to toughness of weld metal after PWHT.
{"title":"Characterization of nanoscale precipitates and enhanced mechanical properties of high strength weld metals containing Cu additions after PWHT","authors":"Jiamei Wang, X. Di, Chengning Li, Dong-po Wang","doi":"10.1051/metal/2022007","DOIUrl":"https://doi.org/10.1051/metal/2022007","url":null,"abstract":"In order to match rapidly development of high strength low alloy steels, the new metal cored wire contained copper was designed. The multi-pass weld metals were obtained by gas metal arc welding. Results show that microstructure of weld metals is bainite with M-A constituents, and there are nano-9RCu precipitates after PWHT. The weld metal as welded achieves 737 MPa of yield strength (YS) and 1097 MPa of ultimate tensile strength (UTS), with an elongation 8%. After PWHT, the YS and UTS are 725 MPa and 968 MPa, respectively, and elongation increases to 16%. The lower dislocations density and reduction of Cu element at solid solution state hence for the decrease of YS. As well, the nano-Cu precipitates and reduction of effective grain size make it increase. The combined effect of these factors makes YS decrease by only 12 MPa after PWHT. Besides, a good impact performance (46.6 J) can be obtained after PWHT, while it is only 27.7 J of weld metals as welded. The improved toughness of weld metals after PWHT is obtained by the contributions of finer effective grain size, soft bainite, and dispersed nano-9RCu precipitation. The nano-Cu precipitates can improve strength without damage to toughness of weld metal after PWHT.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"79 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85662222","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 traditional symmetrical rolling process may result in the insufficient central deformation of the heavy steel plate. The gradient temperature rolling (GTR) based on the ultra-fast cooling was adopted in order to improve the central deformation and keep the deformation along the thickness to be well distributed. The temperature and strain field of the gradient temperature rolling were obtained by the thermo-mechanical coupling finite element method combined with different surface heat transfer coefficient, plate thickness, work roll diameters and so on. The calculated results showed that the deformation was more likely to penetrate into the core compared with uniform temperature rolling (UTR). The central equivalent strain with GTR was increased by 44.3% maximum compared with UTR in the same case. The deformation along the thickness was well distributed compared to the UTR. The central deformation gradually increases with the increase of reduction rate, surface heat transfer coefficient, work roll diameters and speed ratio, while the central deformation almost unchanged with linear velocity. Furthermore, industrial application showed the deformation can penetrate into the core compared with the UTR and it can help to eliminate the band structure. In this study, the influencing law of equivalent strain along the thickness with different parameters was summarized. The fitting model to calculate the central equivalent strain after GTR was established according to the numerical results. It can provide reliable theory and technology support for the setting of various parameters for GTR.
{"title":"The central deformation calculation and analysis of the heavy steel plate for the gradient temperature rolling","authors":"Lian-yun Jiang, Heng Li, Yao-yu Wei, Zhen-Lei Li, Zhi Huang","doi":"10.1051/metal/2022006","DOIUrl":"https://doi.org/10.1051/metal/2022006","url":null,"abstract":"The traditional symmetrical rolling process may result in the insufficient central deformation of the heavy steel plate. The gradient temperature rolling (GTR) based on the ultra-fast cooling was adopted in order to improve the central deformation and keep the deformation along the thickness to be well distributed. The temperature and strain field of the gradient temperature rolling were obtained by the thermo-mechanical coupling finite element method combined with different surface heat transfer coefficient, plate thickness, work roll diameters and so on. The calculated results showed that the deformation was more likely to penetrate into the core compared with uniform temperature rolling (UTR). The central equivalent strain with GTR was increased by 44.3% maximum compared with UTR in the same case. The deformation along the thickness was well distributed compared to the UTR. The central deformation gradually increases with the increase of reduction rate, surface heat transfer coefficient, work roll diameters and speed ratio, while the central deformation almost unchanged with linear velocity. Furthermore, industrial application showed the deformation can penetrate into the core compared with the UTR and it can help to eliminate the band structure. In this study, the influencing law of equivalent strain along the thickness with different parameters was summarized. The fitting model to calculate the central equivalent strain after GTR was established according to the numerical results. It can provide reliable theory and technology support for the setting of various parameters for GTR.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"2011 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87945836","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}
Siyi Ma, Ruiming Su, Kaining Wang, Lei Wang, Y. Qu, Rong-de Li
A recently developed AA7075 was subjected to solid solution, high temperature laser surface treatment, deep cryogenic treatment, and artificial aging. The microstructure evolution and precipitation behavior were examined, and their effects on corrosion behaviour were analyzed. The results showed that coarse η phases disappeared and a large number of smaller η phases were formed after high temperature laser surface treatment. Most of the phases dissolved into Al matrix during solution and fine η phases precipitated in laser treatment. η′ phases appeared in the high temperature laser surface treatment samples. Mg element precipitated in deep cryogenic treatment. It was concluded that the precipitation of AA7075 during heat treatment followed the sequence of solid solution → GPI (Guinier Preston) zones → metastable η′ → stable η. Reasonable laser scanning power owned the best corrosion resistance. The reasonable sample which the laser power was 1000 W showed much better corrosion resistance due to the coarsening and separation of grain boundary precipitations.
{"title":"Influence of laser pre-precipitation on the corrosion resistance of Al-Zn-Mg-Cu alloy with deep cryogenic treatment","authors":"Siyi Ma, Ruiming Su, Kaining Wang, Lei Wang, Y. Qu, Rong-de Li","doi":"10.1051/metal/2022009","DOIUrl":"https://doi.org/10.1051/metal/2022009","url":null,"abstract":"A recently developed AA7075 was subjected to solid solution, high temperature laser surface treatment, deep cryogenic treatment, and artificial aging. The microstructure evolution and precipitation behavior were examined, and their effects on corrosion behaviour were analyzed. The results showed that coarse η phases disappeared and a large number of smaller η phases were formed after high temperature laser surface treatment. Most of the phases dissolved into Al matrix during solution and fine η phases precipitated in laser treatment. η′ phases appeared in the high temperature laser surface treatment samples. Mg element precipitated in deep cryogenic treatment. It was concluded that the precipitation of AA7075 during heat treatment followed the sequence of solid solution → GPI (Guinier Preston) zones → metastable η′ → stable η. Reasonable laser scanning power owned the best corrosion resistance. The reasonable sample which the laser power was 1000 W showed much better corrosion resistance due to the coarsening and separation of grain boundary precipitations.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"31 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89784103","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}
Mei Yang, Shuang Li, Xianju Zhang, Honglang Yang, L. Nie, Xin Wu
Titanium alloy is an important metal material with excellent specific strength, which is widely used in aerospace field, nuclear industry, chemical medicine, and military industry. In order to investigate the connection conditions of TC4 titanium alloy and 316L stainless steel at different temperatures, the braze welding measurement with Ti57Zr13Cu21Ni9 filler metal was conducted in vacuum. The microstructure, morphology and phase of the joint were characterized by SEM (scanning electron microscope), EDS (Energy Dispersive Spectrometer) and XRD (X-ray diffraction), respectively. Microhardness and shear strength of the joint at room temperature and the bonding mechanism of TC4 and 316L were also investigated. The obtained results revealed that the main phases in the diffusion layer were Ti-based solid solution and Ti-Fe (TiFe and TiFe2) intermetallic compoundsands (IMCs) the center of the braze was mainly composed of Ti-Fe IMCs, (Ti, Zr)2(Ni, Cu), Ti-based solid solution. Additionally, the increase of brazing temperature firstly increased and then decreased the average shear strength with the maximum value of 133.9 MPa at 960 °C.
钛合金是一种重要的金属材料，具有优异的比强度，广泛应用于航空航天、核工业、化学医药、军工等领域。为了研究TC4钛合金与316L不锈钢在不同温度下的连接情况，在真空条件下对Ti57Zr13Cu21Ni9钎料进行了钎焊试验。采用扫描电镜(SEM)、能谱仪(EDS)和x射线衍射仪(XRD)对接头的微观结构、形貌和物相进行了表征。对接头的室温显微硬度和抗剪强度以及TC4与316L的结合机理进行了研究。结果表明:扩散层的主要相为Ti基固溶体和Ti- fe (TiFe和TiFe2)金属间化合物(IMCs)，钎焊中心主要由Ti- fe IMCs、(Ti, Zr)2(Ni, Cu)、Ti基固溶体组成。随着钎焊温度的升高，平均抗剪强度先升高后降低，在960℃时达到最大值133.9 MPa。
{"title":"Effect of brazing temperatures on microstructure and properties of TC4/Ti57Zr13Cu21Ni9/316L","authors":"Mei Yang, Shuang Li, Xianju Zhang, Honglang Yang, L. Nie, Xin Wu","doi":"10.1051/metal/2021099","DOIUrl":"https://doi.org/10.1051/metal/2021099","url":null,"abstract":"Titanium alloy is an important metal material with excellent specific strength, which is widely used in aerospace field, nuclear industry, chemical medicine, and military industry. In order to investigate the connection conditions of TC4 titanium alloy and 316L stainless steel at different temperatures, the braze welding measurement with Ti57Zr13Cu21Ni9 filler metal was conducted in vacuum. The microstructure, morphology and phase of the joint were characterized by SEM (scanning electron microscope), EDS (Energy Dispersive Spectrometer) and XRD (X-ray diffraction), respectively. Microhardness and shear strength of the joint at room temperature and the bonding mechanism of TC4 and 316L were also investigated. The obtained results revealed that the main phases in the diffusion layer were Ti-based solid solution and Ti-Fe (TiFe and TiFe2) intermetallic compoundsands (IMCs) the center of the braze was mainly composed of Ti-Fe IMCs, (Ti, Zr)2(Ni, Cu), Ti-based solid solution. Additionally, the increase of brazing temperature firstly increased and then decreased the average shear strength with the maximum value of 133.9 MPa at 960 °C.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"75 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80933777","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}
Z. Shi, Mengjie Dong, Yufu Sun, Jiangtao Ma, Xueshan Du, Jingyu Zhao
The effects of austempering time on the structure and properties of high-strength austempered ductile iron were studied by using optical microscopy (OM), X-ray diffractometer (XRD) and scanning electron microscope (SEM). The results show that the matrix structure of austempered ductile iron (ADI) consists of acicular ferrite and retained austenite. With the increase of austempering time, the content of acicular ferrite increases and the content of retained austenite first increases and then decreases, which results in tensile strength, elongation and impact toughness increase whereas hardness and wear resistance decreases. The fracture characteristics of the ADI specimens change from brittle fracture to ductile fracture with the increase of austempering time. ADI has excellent comprehensive mechanical properties after austenitizing at 900 °C for 90 min and then austempering at 250 °C for 120 min.
{"title":"Effects of austempering time on the microstructure and properties of austempered ductile iron","authors":"Z. Shi, Mengjie Dong, Yufu Sun, Jiangtao Ma, Xueshan Du, Jingyu Zhao","doi":"10.1051/metal/2022011","DOIUrl":"https://doi.org/10.1051/metal/2022011","url":null,"abstract":"The effects of austempering time on the structure and properties of high-strength austempered ductile iron were studied by using optical microscopy (OM), X-ray diffractometer (XRD) and scanning electron microscope (SEM). The results show that the matrix structure of austempered ductile iron (ADI) consists of acicular ferrite and retained austenite. With the increase of austempering time, the content of acicular ferrite increases and the content of retained austenite first increases and then decreases, which results in tensile strength, elongation and impact toughness increase whereas hardness and wear resistance decreases. The fracture characteristics of the ADI specimens change from brittle fracture to ductile fracture with the increase of austempering time. ADI has excellent comprehensive mechanical properties after austenitizing at 900 °C for 90 min and then austempering at 250 °C for 120 min.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"179 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90648956","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 gas–solid reaction decarburisation of cast iron strips is a direct steel production method with low production costs. In this study, the decarburisation kinetics of Fe-C alloy strips in an Ar-CO-CO2 atmosphere were investigated. Fe-C alloy strips with 4.2 wt.% C and different thicknesses (1, 1.5, and 2 mm) were used for the decarburisation experiments under temperatures of 1293, 1353, and 1413 K. The results indicate that, under appropriate mixed gas conditions, rapid decarburisation can be achieved. With an increase in the decarburisation temperature, the decarburisation rate increases significantly. Under the same decarburisation temperature and time, thinner Fe-C alloy strips exhibit a better decarburisation effect. The decarburisation process includes three rate-limiting stages, namely gas and surface reaction, carbon diffusion, and cementite decomposition. The microstructure of the decarburised strips comprises a complete decarburised layer and a partial decarburised layer, and the thickness of the complete decarburised layer increases with decarburisation time. The decarburisation of the Fe-C alloy strip is an apparent first-order reaction with an activation energy of 124.7 kJ ∙ mol−1, and the activation energy for the growth of the complete decarburised layer is 132.3 kJ ∙ mol−1. The results of this study can help develop more efficient and cost-effective steel production methods.
{"title":"Decarburisation of Fe-C alloy strips by gas–solid reaction in Ar-CO-CO2","authors":"Meijie Zhou, L. Ai, Lu-kuo Hong, Cai-jiao Sun, Yuqing Zhou, Fanjun Meng","doi":"10.1051/metal/2021092","DOIUrl":"https://doi.org/10.1051/metal/2021092","url":null,"abstract":"The gas–solid reaction decarburisation of cast iron strips is a direct steel production method with low production costs. In this study, the decarburisation kinetics of Fe-C alloy strips in an Ar-CO-CO2 atmosphere were investigated. Fe-C alloy strips with 4.2 wt.% C and different thicknesses (1, 1.5, and 2 mm) were used for the decarburisation experiments under temperatures of 1293, 1353, and 1413 K. The results indicate that, under appropriate mixed gas conditions, rapid decarburisation can be achieved. With an increase in the decarburisation temperature, the decarburisation rate increases significantly. Under the same decarburisation temperature and time, thinner Fe-C alloy strips exhibit a better decarburisation effect. The decarburisation process includes three rate-limiting stages, namely gas and surface reaction, carbon diffusion, and cementite decomposition. The microstructure of the decarburised strips comprises a complete decarburised layer and a partial decarburised layer, and the thickness of the complete decarburised layer increases with decarburisation time. The decarburisation of the Fe-C alloy strip is an apparent first-order reaction with an activation energy of 124.7 kJ ∙ mol−1, and the activation energy for the growth of the complete decarburised layer is 132.3 kJ ∙ mol−1. The results of this study can help develop more efficient and cost-effective steel production methods.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"118 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81310517","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}
Mass transfer between liquid steel and slag is an important physical phenomenon during secondary metallurgy for prediction of the chemical reaction rate and adjustment of liquid steel composition. We study this phenomenon at ambient temperature with a water experiment and perform Direct Numerical Simulations, aiming to reproduce an argon-gas bottom-blown ladle. First, we measure the evolution of the time-averaged open-eye area as a function of the air flow rate. Both simulation and experiment agree relatively well and are close to other water experiments in the literature. Secondly, the mass transfer of thymol between water and oil is investigated. The experimental results show that two mass transfer regimes can be observed. The regime change coincides with atomization of the oil layer resulting in the continuous formation of oil droplets in the water whenever the air flow rate rises above a critical value. The numerical results for the mass-transfer rate or Sherwood number are obtained at small Schmidt numbers and are then extrapolated to the experimental Schmidt number of 1480. A good agreement with experiment is observed although with large error bars. The Sherwood numbers at the two largest simulated flow rates show a steep increase.
{"title":"Experimental and numerical modelling of mass transfer in a refining ladle","authors":"Nelson Joubert, P. Gardin, S. Popinet, S. Zaleski","doi":"10.1051/metal/2021088","DOIUrl":"https://doi.org/10.1051/metal/2021088","url":null,"abstract":"Mass transfer between liquid steel and slag is an important physical phenomenon during secondary metallurgy for prediction of the chemical reaction rate and adjustment of liquid steel composition. We study this phenomenon at ambient temperature with a water experiment and perform Direct Numerical Simulations, aiming to reproduce an argon-gas bottom-blown ladle. First, we measure the evolution of the time-averaged open-eye area as a function of the air flow rate. Both simulation and experiment agree relatively well and are close to other water experiments in the literature. Secondly, the mass transfer of thymol between water and oil is investigated. The experimental results show that two mass transfer regimes can be observed. The regime change coincides with atomization of the oil layer resulting in the continuous formation of oil droplets in the water whenever the air flow rate rises above a critical value. The numerical results for the mass-transfer rate or Sherwood number are obtained at small Schmidt numbers and are then extrapolated to the experimental Schmidt number of 1480. A good agreement with experiment is observed although with large error bars. The Sherwood numbers at the two largest simulated flow rates show a steep increase.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"30 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83994172","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}
In the present work, nano-hydroxyapatite (HA) was used as dispersing phase to develop Ti based composites. The mixture of powders with 5% and 10% HA and remaining being Ti were ball milled for 20 h. The ball milled powders were characterized by X-Ray diffraction analysis, electron microscopy. The powders were then sintered at 850 °C in vacuum. Higher surface energies were observed for the composites compared with medical grade purer Ti calculated from the water contact angles. This can be attributed to the smaller grain size and the presence of nano-HA in the composites. Immersion studies carried out in simulated body fluid for 4 weeks demonstrated excellent bioactivity for the composite as reflected from the higher mineral deposition from the SBF. This can be explained by considering the effect of higher wettability and added nano-HA in the composites. All the samples were found to be nontoxic against 3T3 cells as observed from the cytotoxicity test using MTT assay. Hence, from the results, it can be understood that bioactive Ti-HA composites can be produced from ball milling and sintering which exhibit excellent bioactivity to promote higher healing rate.
{"title":"Titanium-nanohydroxyapatite composites produced by ball milling and sintering: wettability, bioactivity and toxicity studies","authors":"E. Krishna, G. Suresh","doi":"10.1051/metal/2022005","DOIUrl":"https://doi.org/10.1051/metal/2022005","url":null,"abstract":"In the present work, nano-hydroxyapatite (HA) was used as dispersing phase to develop Ti based composites. The mixture of powders with 5% and 10% HA and remaining being Ti were ball milled for 20 h. The ball milled powders were characterized by X-Ray diffraction analysis, electron microscopy. The powders were then sintered at 850 °C in vacuum. Higher surface energies were observed for the composites compared with medical grade purer Ti calculated from the water contact angles. This can be attributed to the smaller grain size and the presence of nano-HA in the composites. Immersion studies carried out in simulated body fluid for 4 weeks demonstrated excellent bioactivity for the composite as reflected from the higher mineral deposition from the SBF. This can be explained by considering the effect of higher wettability and added nano-HA in the composites. All the samples were found to be nontoxic against 3T3 cells as observed from the cytotoxicity test using MTT assay. Hence, from the results, it can be understood that bioactive Ti-HA composites can be produced from ball milling and sintering which exhibit excellent bioactivity to promote higher healing rate.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"15 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90014553","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}
Tingsong Yang, Yingwei Wang, Haijun Wang, Yang Hai, Feng-shan Du
Roll profile electromagnetic control technology (RPECT) is a new strip flatness control technology that changes roll gap shape by controlling the roll profiles of electromagnetic control rolls (ECRs). To address the randomness of the flatness defect locations, this paper proposes an external adjustment method for RPECT roll profiles based on the segmented cooling principle. Based on the layout of the cooling areas and electromagnetic sticks, an electromagnetic-thermal-structural coupled model is established to analyse roll profile variations. The results show that symmetrically changing the cooling intensities of the different cooling areas can increase or decrease the roll crown of the ECR, while asymmetrically changing the cooling intensities of the different cooling areas can change the position of the maximum bulging point of the ECR. Variations in the component cooling ratio coefficient impact the effects of different cooling strategies, which needs to be considered when selecting the cooling strategy configuration scheme. Compared the maximum bulging values, radial temperature gradients and axial temperature gradients of different electromagnetic stick (ES) structures, the regulation law reverses when the length of the ES is too small, and the variation of the law is very small. Therefore, different ES structures have different segmented cooling regulation characteristics.
{"title":"Research on an external adjustment method for RPECT roll profiles based on the segmented cooling principle","authors":"Tingsong Yang, Yingwei Wang, Haijun Wang, Yang Hai, Feng-shan Du","doi":"10.1051/metal/2021098","DOIUrl":"https://doi.org/10.1051/metal/2021098","url":null,"abstract":"Roll profile electromagnetic control technology (RPECT) is a new strip flatness control technology that changes roll gap shape by controlling the roll profiles of electromagnetic control rolls (ECRs). To address the randomness of the flatness defect locations, this paper proposes an external adjustment method for RPECT roll profiles based on the segmented cooling principle. Based on the layout of the cooling areas and electromagnetic sticks, an electromagnetic-thermal-structural coupled model is established to analyse roll profile variations. The results show that symmetrically changing the cooling intensities of the different cooling areas can increase or decrease the roll crown of the ECR, while asymmetrically changing the cooling intensities of the different cooling areas can change the position of the maximum bulging point of the ECR. Variations in the component cooling ratio coefficient impact the effects of different cooling strategies, which needs to be considered when selecting the cooling strategy configuration scheme. Compared the maximum bulging values, radial temperature gradients and axial temperature gradients of different electromagnetic stick (ES) structures, the regulation law reverses when the length of the ES is too small, and the variation of the law is very small. Therefore, different ES structures have different segmented cooling regulation characteristics.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"35 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78366887","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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