The microstructure and texture evolution of Mg-xAl-1Zn-1Y-0.1Mn alloys are systematically analyzed.There is no effect of Al addition on grain refinement in the Mg-1Zn-1Y-0.1Mn alloy,but the addition of 0.5 wt.%or more...The microstructure and texture evolution of Mg-xAl-1Zn-1Y-0.1Mn alloys are systematically analyzed.There is no effect of Al addition on grain refinement in the Mg-1Zn-1Y-0.1Mn alloy,but the addition of 0.5 wt.%or more Al element dramatically changes texture from a weak texture to a strong basal texture.The predominant second phase particle of Mg_(3)Zn_(3)Y_(2) phase in the Mg-1Zn-1Y-0.1Mn alloy changes to Al_(2)Y phase by the addition of only 0.1 wt.%Al element,and the concentrations of dissolved Y element in the 0Al,0.1Al,0.3Al,0.5Al and 1Al alloys are 0.50,0.31,0.23,0.15 and 0.06 wt.%,respectively.Although the 0.5 wt.%or more Al-added alloys have higher Schmid factor for prismatic(a)slip than the 0.3 wt.%or less Al-added alloys,the lower Al containing alloys show much higher activity of prismatic (a)slip than the higher Al containing alloys.It demonstrates that the addition of high amount of Al element in Mg-Zn-RE alloy dramatically decrease the dissolved Y element,resulting in a significant deterioration of activity of prismaticslip and consequently a poor formability at room temperature.展开更多
The present study proposes a methodology for predicting the mechanical properties of AZ61 and AZ91alloys associated with microstructure,texture and aging parameters and estimating predictor importance.For this,we inve...The present study proposes a methodology for predicting the mechanical properties of AZ61 and AZ91alloys associated with microstructure,texture and aging parameters and estimating predictor importance.For this,we investigate quantitative correlations between microstructure,texture and mechanical properties of aged AZ61 and AZ91 rods through machine learning.This regression analysis focuses on the precipitation behavior of Mg17Al12as the main second phase of Mg-Al-Zn alloys with respect to aging conditions.To simplify data generation,only SEM images were used to quantify the features of discontinuous and continuous precipitates.To overcome the lack of data and make the most of the measured data,we devised a method to extend the existing dataset by a factor of 9 using the mean and standard deviation of the measured data.Artificial neural networks predicted tensile and compressive yield strengths and resultant yield asymmetry with a high accuracy of over 98%using 11 predictors for a total of 288datasets.Decision tree learning quantitatively assessed the importance of predictors in determining the mechanical properties of aged AZ61 and AZ91 rods.展开更多
In this study,the effects of Al addition on the corrosion behavior of pure Mg with controlled impurity contents were systematically analyzed according to the processing history.The results revealed that the corrosion ...In this study,the effects of Al addition on the corrosion behavior of pure Mg with controlled impurity contents were systematically analyzed according to the processing history.The results revealed that the corrosion behavior of high-purity Mg-Al alloys is strongly related to changes in the microstructure,including theβphase and Al-Mn or Al-Fe phases,and the protectiveness of the surface film according to the Al content and processing history.In the as-cast alloys,the corrosion rate increased due to the increase ofβphase as the Al content increased,but in the as-extruded alloys,the corrosion rate,which was high due to intermetallic compounds caused by impurities in the low Al alloy,decreased as the Al content increased,and then increased again.This is due to the combined effect of the increase of theβphase and decrease of the impurity effect,and the increase of the dissolved Al content.The results suggest that it is necessary to analyze the effect of alloying elements on the corrosion behavior of pure Mg with information concerning the impurity content and processing history.展开更多
The effects of various alloying elements on the performance of Mg-Mg_(2)Ni hydrogen storage alloys were investigated by performing firstprinciples density functional theory calculations.We examined the important chara...The effects of various alloying elements on the performance of Mg-Mg_(2)Ni hydrogen storage alloys were investigated by performing firstprinciples density functional theory calculations.We examined the important characteristics of hydrogen storage alloys by considering both Mg-based solid solution and Mg_(2)Ni-based intermetallic compound phases,where the hydride forms are Mg H2and Mg_(2)NiH4,respectively.In particular,qualitatively valid information for predicting changes in plateau pressures in the pressure-composition-temperature(PCT)curve was provided by calculating changes in the energy of related hydrogenation reactions.The effects of alloying elements on volume changes due to hydrogenation reactions were also obtained to provide additional criteria for the practical use of hydrogen storage alloys.For the Mg_(2)Ni-based intermetallic compound,we examined the site preference of each alloying element,considering the designated stoichiometry of the base alloy.Based on the revealed site preferences,the effects of various possible alloying elements on the properties of Mg_(2)Ni-based hydrides were also examined.Electronic structure analyses were further conducted to elucidate the detailed mechanisms underlying the role of the additional solute elements.展开更多
基金financially supported by the Fundamental Research Program of the Korea Institute of Materials Science(Grant No.360–05–04-PNKA540)the National Research Foundation of Korea(CRC23011–210).
文摘The microstructure and texture evolution of Mg-xAl-1Zn-1Y-0.1Mn alloys are systematically analyzed.There is no effect of Al addition on grain refinement in the Mg-1Zn-1Y-0.1Mn alloy,but the addition of 0.5 wt.%or more Al element dramatically changes texture from a weak texture to a strong basal texture.The predominant second phase particle of Mg_(3)Zn_(3)Y_(2) phase in the Mg-1Zn-1Y-0.1Mn alloy changes to Al_(2)Y phase by the addition of only 0.1 wt.%Al element,and the concentrations of dissolved Y element in the 0Al,0.1Al,0.3Al,0.5Al and 1Al alloys are 0.50,0.31,0.23,0.15 and 0.06 wt.%,respectively.Although the 0.5 wt.%or more Al-added alloys have higher Schmid factor for prismatic(a)slip than the 0.3 wt.%or less Al-added alloys,the lower Al containing alloys show much higher activity of prismatic (a)slip than the higher Al containing alloys.It demonstrates that the addition of high amount of Al element in Mg-Zn-RE alloy dramatically decrease the dissolved Y element,resulting in a significant deterioration of activity of prismaticslip and consequently a poor formability at room temperature.
基金financially supported by the Fundamental Research Program(PNK6960)of the Korea Institute of Materials Science(KIMS)。
文摘The present study proposes a methodology for predicting the mechanical properties of AZ61 and AZ91alloys associated with microstructure,texture and aging parameters and estimating predictor importance.For this,we investigate quantitative correlations between microstructure,texture and mechanical properties of aged AZ61 and AZ91 rods through machine learning.This regression analysis focuses on the precipitation behavior of Mg17Al12as the main second phase of Mg-Al-Zn alloys with respect to aging conditions.To simplify data generation,only SEM images were used to quantify the features of discontinuous and continuous precipitates.To overcome the lack of data and make the most of the measured data,we devised a method to extend the existing dataset by a factor of 9 using the mean and standard deviation of the measured data.Artificial neural networks predicted tensile and compressive yield strengths and resultant yield asymmetry with a high accuracy of over 98%using 11 predictors for a total of 288datasets.Decision tree learning quantitatively assessed the importance of predictors in determining the mechanical properties of aged AZ61 and AZ91 rods.
基金the main research program of the Korea Institute of Materials Science(Grant No.PNK8150)for financially supporting this study
文摘In this study,the effects of Al addition on the corrosion behavior of pure Mg with controlled impurity contents were systematically analyzed according to the processing history.The results revealed that the corrosion behavior of high-purity Mg-Al alloys is strongly related to changes in the microstructure,including theβphase and Al-Mn or Al-Fe phases,and the protectiveness of the surface film according to the Al content and processing history.In the as-cast alloys,the corrosion rate increased due to the increase ofβphase as the Al content increased,but in the as-extruded alloys,the corrosion rate,which was high due to intermetallic compounds caused by impurities in the low Al alloy,decreased as the Al content increased,and then increased again.This is due to the combined effect of the increase of theβphase and decrease of the impurity effect,and the increase of the dissolved Al content.The results suggest that it is necessary to analyze the effect of alloying elements on the corrosion behavior of pure Mg with information concerning the impurity content and processing history.
基金National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Grant No.NRF-2022M3D1A2095313)National Research Council of Science&Technology(NST)grant by the Korea government(MSIT)(No.GTL24051-300)+2 种基金Ministry of Trade,Industry and Energy through machinery and equipment industry technology development project(Grant No.20018661)support from the Korea Institute of Industrial Technology(KITECH EH-24-0007)support from the National Supercomputing Center with supercomputing resources including technical support(KSC-2021-CRE0402)。
文摘The effects of various alloying elements on the performance of Mg-Mg_(2)Ni hydrogen storage alloys were investigated by performing firstprinciples density functional theory calculations.We examined the important characteristics of hydrogen storage alloys by considering both Mg-based solid solution and Mg_(2)Ni-based intermetallic compound phases,where the hydride forms are Mg H2and Mg_(2)NiH4,respectively.In particular,qualitatively valid information for predicting changes in plateau pressures in the pressure-composition-temperature(PCT)curve was provided by calculating changes in the energy of related hydrogenation reactions.The effects of alloying elements on volume changes due to hydrogenation reactions were also obtained to provide additional criteria for the practical use of hydrogen storage alloys.For the Mg_(2)Ni-based intermetallic compound,we examined the site preference of each alloying element,considering the designated stoichiometry of the base alloy.Based on the revealed site preferences,the effects of various possible alloying elements on the properties of Mg_(2)Ni-based hydrides were also examined.Electronic structure analyses were further conducted to elucidate the detailed mechanisms underlying the role of the additional solute elements.
