The reactions between Ti and Al-Mg alloys were systematically investigated by heating the Ti/Al-Mg al-loy powder mixture compacts with Mg contents ranging from 5.09 to 40.36 wt.%at 660°C.Mg element in the Al-Mg a...The reactions between Ti and Al-Mg alloys were systematically investigated by heating the Ti/Al-Mg al-loy powder mixture compacts with Mg contents ranging from 5.09 to 40.36 wt.%at 660°C.Mg element in the Al-Mg alloys contributed to the breakage of the oxide films on the surfaces of the Ti and Al-Mg alloy powders,thus,promoting the reactions.In the samples with Mg contents varying from 5.09 wt.%to 25.93 wt.%,the first-formed intermetallic compound was Al_(18)Ti_(2)Mg_(3),and then Al_(3)Ti generated at the Al_(18)Ti_(2)Mg_(3)/Ti interface.Since the Mg content in the Al-Mg melts decreased during the subsequent heat-ing process,the previously formed Al_(18)Ti_(2)Mg_(3)in the Ti/Al-5.09Mg sample transformed into Al_(3)Ti accom-panied by the reaction of Al with Ti to newly form Al_(3)Ti,generating a single Al_(3)Ti phase.In contrast,the new formation of Al_(3)Ti and its transformation to Al_(18)Ti_(2)Mg_(3)proceeded continuously in the Ti/Al-13.54Mg and Ti/Al-25.94Mg samples,resulting in a mixture of Al_(18)Ti_(2)Mg_(3)and a little Al_(3)Ti residue.In the Ti/Al-40.54Mg sample,Al_(3)Ti was the unique reaction product throughout the heating process.The final Al_(3)Ti particles in the Ti/Al-5.09Mg sample were in a blocky shape,while they were in a plate-like form in the Ti/Al-40.54Mg sample,which was caused by the enhanced growth anisotropy due to the de-creased interfacial energy between Al_(3)Ti particles and Al-Mg melts with the increase of Mg content.A twin plane re-entrant mechanism was suggested for the growth of Al_(18)Ti_(2)Mg_(3)particles,weakening the anisotropic growth caused by the directional supply of Ti atoms,and contributing to the blocky mor-phology of Al_(18)Ti_(2)Mg_(3)particles.In addition,the volume difference between the formed Al_(18)Ti_(2)Mg_(3)and consumed Ti was greater than that between the Al_(3)Ti and Ti,and the Al_(18)Ti_(2)Mg_(3)has worse plasticity than the Al_(3)Ti,resulting in the Al_(18)Ti_(2)Mg_(3)reaction product fracturing more easily during thickening,thus forming a petal-like structure,but the Al_(3)Ti product being in an almost continuous layer.展开更多
The Portevin–Le Chatelier（PLC） effect in Al–2.30wt%Mg, Al–4.57wt%Mg and Al–6.91wt%Mg alloys has been investigated at various applied strain rates at room temperature in this study. Three-dimensional digital imag...The Portevin–Le Chatelier（PLC） effect in Al–2.30wt%Mg, Al–4.57wt%Mg and Al–6.91wt%Mg alloys has been investigated at various applied strain rates at room temperature in this study. Three-dimensional digital image correlation（3D-DIC） technique was applied to obtaining the further insight into the spatiotemporal characteristics, in particular the influence of Mg content on deformation behaviors. Mg content has a pronounced effect on serration characteristics, including the serration type and amplitude; Mg content tends to weaken the spatial correlation of the propagative bands. Additionally, the serration amplitude linearly increases with the maximum PLC band strain; high Mg content generates a higher PLC band strain at a given serration amplitude compared with low Mg content. Mg content is found to be effective to enhance the serration amplitude, the maximum PLC band strain and also the amount of elastic shrinkage outside PLC bands.展开更多
Effects of Mg content on the microstructure and mechanical properties of low Zn-containing Al−xMg−3Zn−1Cu cast alloys(x=3−5,wt.%)were investigated.As Mg content increased in the as-cast alloys,the grains were refined ...Effects of Mg content on the microstructure and mechanical properties of low Zn-containing Al−xMg−3Zn−1Cu cast alloys(x=3−5,wt.%)were investigated.As Mg content increased in the as-cast alloys,the grains were refined due to enhanced growth restriction,and the formation ofη-Mg(AlZnCu)_(2) and S-Al_(2)CuMg phases was inhibited while the formation of T-Mg_(32)(AlZnCu)_(49 )phase was promoted when Mg content exceeded 4 wt.%.The increase of Mg content encumbered the solution kinetics by increasing the size of eutectic phase but accelerated and enhanced the age-hardening through expediting precipitation kinetics and elevating the number density of the precipitates.As Mg content increased,the yield strength and tensile strength of the as-cast,solution-treated and peak-aged alloys were severally improved,while the elongation of the alloys decreased.The tensile strength and elongation of the peak-aged Al−5Mg−3Zn−1Cu alloy exceed 500 MPa and 5%,respectively.Precipitation strengthening implemented by T′precipitates is the predominant strengthening mechanism in the peak-aged alloys and is enhanced by increasing Mg content.展开更多
To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properti...To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properties of the SLM-fabricated Al−Mg−Mn−Sc−Zr alloy were systematically investigated by density measurement,microstructure characterization,and tensile testing.The results revealed that dense samples could be obtained by adjusting the SLM process parameters.The alloy exhibited a fine equiaxed-columnar bimodal grain microstructure.The presence of primary Al3Sc andα-Al(Mn,Fe)Si particles contributed to the grain refinement of the alloy with an average grain size of 4.63μm.Upon aging treatment at 350°C for 2 h,the strength and elongation of the alloy were simultaneously improved due to the precipitation of Al3Sc nanoparticles and the formation of the 9R phase.This study demonstrates that the strength−plasticity trade-off of the aluminum alloy can be overcome by utilizing SLM technology and subsequent post-heat treatment to induce the formation of the long-period stacked ordered phase.展开更多
The Mg content of Zn1-xMgxO film grown on A-sapphire substrates by plasma-assisted molecular beam epitaxy is measured by inductively coupled plasma (ICP) and electronic probe microanalysis (EPMA). A theoretical model ...The Mg content of Zn1-xMgxO film grown on A-sapphire substrates by plasma-assisted molecular beam epitaxy is measured by inductively coupled plasma (ICP) and electronic probe microanalysis (EPMA). A theoretical model for analyzing the difference in the Mg content between Zn-rich and Zn-deficient conditions in the growth process is established, and the mathematical relation between Mg content and the temperature of the Mg cell is formulated under Zn-rich condition. The formula derived is proven to be correct by experiments.展开更多
N-type Mg_(3)Sb_(2)-based alloys have recently attracted considerable attention due to the high thermoelectric performance.However,the performance degradation occurs because of Mg loss at high temperature.Elemental Mg...N-type Mg_(3)Sb_(2)-based alloys have recently attracted considerable attention due to the high thermoelectric performance.However,the performance degradation occurs because of Mg loss at high temperature.Elemental Mg plays a significantly critical role in thermoelectric performance and thermal stability,where most studies on these compounds have thus far concentrated on the nominal Mg content which heavily depends on the fabrication methods,with few attentions devoted to the essential issue of actual Mg content,resulting in the unclear mechanism of improving their stability,severely limiting their practical applications in thermoelectric power generation.Here,we systematically analyzed the thermoelectric performance,thermal stability,and changed micro structures before and after in situ electronic thermoelectric performance measurement at 750 K,for n-type Mg_(3)Sb_(2)-based alloys with different Mg and Co content.It was found that elemental Mg and Co have a similar effect on adjusting the electron transport characteristic,and the peak values of power factor and ZT are up to 32.4μW cm^(-1)K^(-2)and 1.8,respectively.Thermal stability is more sensitive to the Mg content of material matrix than thermoelectric performance,and the effects of Mgpoor condition on thermal stability cannot be compensated via cationic Co doping.We also proved the route of Mg loss in experiments.By balancing Mg content and Co doping,the optimized sample showed good stability,in which it reduced only by 10%over 170 h of measurement at 750 K.Density functional theory calculation showed that the bonding strength of Co-Mg is stronger than MgMg,also explaining the enhanced thermal stability.展开更多
Mg-content cored-wire was used to desulphurize and spheroidize ductile iron melt in industrial experiments. The optimal feeding speed and suitable treatment temperature were determined in the experiments. And cored-wi...Mg-content cored-wire was used to desulphurize and spheroidize ductile iron melt in industrial experiments. The optimal feeding speed and suitable treatment temperature were determined in the experiments. And cored-wire method and pouring method were compared. Conclusions have been drawn that, under these conditions in the experiments, the optimal feeding speed is 15m/min, treatment temperature should be as low as possible, 1400-1450℃ generally; and cored-wire method can act more effective in ductile iron melt desulphurization and spheroid than pouring method.展开更多
In the present study,the effect of Zn content on the microstructure and deformation behavior of the as-cast Mg-Zn-Y-Nd alloy has been investigated.The results showed that as Zn content increased,the volume fraction of...In the present study,the effect of Zn content on the microstructure and deformation behavior of the as-cast Mg-Zn-Y-Nd alloy has been investigated.The results showed that as Zn content increased,the volume fraction of secondary phases increased.Moreover,the phase transformation from W-phase to W-phase and I-phase occurred.In the as-cast state,W-phase exists as eutectic and large block form.When Zn content increases to 6 and 8%（wt%）,small I-phase could precipitate around W-phase particles.Additionally,the effect of Zn content on the tensile properties and deformation behavior varies with the testing temperature.At room temperature,the tensile strength increases with Zn content,whereas the elongation increases initially and then decreases.At 250℃,as Zn content increases,the tensile strength decreases initially and then increases slightly,whereas the elongation decreases.At 350℃,the elongation increases with Zn content,whereas the tensile strength decreases initially and then increases slightly.展开更多
In order to improve the cyclic stability of La-Mg-Ni system （Ce2Ni7-type） alloy electrode, small amount of Co was added in La0.75Mg0.25Ni3.5 alloy. The effect of Co on electrochemical performance and microstructure ...In order to improve the cyclic stability of La-Mg-Ni system （Ce2Ni7-type） alloy electrode, small amount of Co was added in La0.75Mg0.25Ni3.5 alloy. The effect of Co on electrochemical performance and microstructure of the alloys were investigated in detail. XRD results showed that the alloys had multiphase structure composed of （La, Mg）2Ni7, LaNi5 and small amount of LaNi2 phases. The discharge capacity of the alloys first increased and then decreased with increasing Co content. At a discharge current density of 900 mA/g, the HRD of the alloy electrodes increased from 81.3% （x=0） to 89.2 % （x=0.2）, and then reduced to 87.8 % （x=0.6）. After 60 charge/discharge cycles, the capacity retention rate of the alloys enhanced from 52.67% to 61.32%, and the capacity decay rate of the alloys decreased from 2.60 to 2.05 mAh/g per cycle with increasing Co content. The obtained results by XPS and XRD showed that the fundamental reasons for the capacity decay of the La-Mg-Ni system （Ce2Ni7-type） alloy electrodes were corrosion and oxidation as well as passivation of Mg and Lain alkaline solution.展开更多
By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu...By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu alloys were investigated. The results indicate that the constituents formed during casting alloys are main Al1.9CuMg4.1Si3.3,Al4(MnFe)3Si2 and Mg2Si, while pure Si is only present in the alloy containing lower magnesium content. Increasing Mg content leads to increasing the amount of Mg2Si, but decreasing the amount of Al1.9CuMg4.1Si3.3 and Al4(MnFe)3Si2. During the following homogenization process, Al1.9CuMg4.1Si3.3 is completely dissolved, Al4(MnFe)3Si2 and pure Si remain unchanged. After rolling and final heat treatment, the constituents in the alloys change no longer.展开更多
The doping content of Mg plays an important role in the crystalline structure and morphology properties of Zn_(1-x )Mg_xO thin films. Here,using radio-frequency magnetron sputtering method,we prepared Zn_(1-x )Mg_xO t...The doping content of Mg plays an important role in the crystalline structure and morphology properties of Zn_(1-x )Mg_xO thin films. Here,using radio-frequency magnetron sputtering method,we prepared Zn_(1-x )Mg_xO thin films on single crystalline Si(100) substrates with a series of x values. By means of X-ray diffraction(XRD) and scanning electron microscope(SEM),the crystalline structure and morphology of Zn_(1-x )Mg_xO thin films with different x values are investigated. The crystalline structure of Zn_(1-x )Mg_xO thin film is single phase with x<0.3,while there is phase separation phenomenon with x>0.3,and hexagonal and cubic structures will coexist in Zn_(1-x )Mg_xO thin films with higher x values. Especially with lower x values,a shoulder peak of 35.1° appearing in the XRD pattern indicates a double-crystalline structure of Zn_(1-x )Mg_xO thin film. The crystalline quality has been improved and the inner stress has been released,after the Zn_(1-x )Mg_xO thin films were annealed at 600 °C in vacuum condition.展开更多
基金the National Key Re-search and Development Program(Grant No.2018YFB2001800)the National Natural Science Foundation of China(Grant No.51564035).
文摘The reactions between Ti and Al-Mg alloys were systematically investigated by heating the Ti/Al-Mg al-loy powder mixture compacts with Mg contents ranging from 5.09 to 40.36 wt.%at 660°C.Mg element in the Al-Mg alloys contributed to the breakage of the oxide films on the surfaces of the Ti and Al-Mg alloy powders,thus,promoting the reactions.In the samples with Mg contents varying from 5.09 wt.%to 25.93 wt.%,the first-formed intermetallic compound was Al_(18)Ti_(2)Mg_(3),and then Al_(3)Ti generated at the Al_(18)Ti_(2)Mg_(3)/Ti interface.Since the Mg content in the Al-Mg melts decreased during the subsequent heat-ing process,the previously formed Al_(18)Ti_(2)Mg_(3)in the Ti/Al-5.09Mg sample transformed into Al_(3)Ti accom-panied by the reaction of Al with Ti to newly form Al_(3)Ti,generating a single Al_(3)Ti phase.In contrast,the new formation of Al_(3)Ti and its transformation to Al_(18)Ti_(2)Mg_(3)proceeded continuously in the Ti/Al-13.54Mg and Ti/Al-25.94Mg samples,resulting in a mixture of Al_(18)Ti_(2)Mg_(3)and a little Al_(3)Ti residue.In the Ti/Al-40.54Mg sample,Al_(3)Ti was the unique reaction product throughout the heating process.The final Al_(3)Ti particles in the Ti/Al-5.09Mg sample were in a blocky shape,while they were in a plate-like form in the Ti/Al-40.54Mg sample,which was caused by the enhanced growth anisotropy due to the de-creased interfacial energy between Al_(3)Ti particles and Al-Mg melts with the increase of Mg content.A twin plane re-entrant mechanism was suggested for the growth of Al_(18)Ti_(2)Mg_(3)particles,weakening the anisotropic growth caused by the directional supply of Ti atoms,and contributing to the blocky mor-phology of Al_(18)Ti_(2)Mg_(3)particles.In addition,the volume difference between the formed Al_(18)Ti_(2)Mg_(3)and consumed Ti was greater than that between the Al_(3)Ti and Ti,and the Al_(18)Ti_(2)Mg_(3)has worse plasticity than the Al_(3)Ti,resulting in the Al_(18)Ti_(2)Mg_(3)reaction product fracturing more easily during thickening,thus forming a petal-like structure,but the Al_(3)Ti product being in an almost continuous layer.
基金financial support received from the National Natural Science Foundation of China (NSFC) under Grant Nos. 11332010, 51571013, 51271174, 11472266 and 11428206
文摘The Portevin–Le Chatelier（PLC） effect in Al–2.30wt%Mg, Al–4.57wt%Mg and Al–6.91wt%Mg alloys has been investigated at various applied strain rates at room temperature in this study. Three-dimensional digital image correlation（3D-DIC） technique was applied to obtaining the further insight into the spatiotemporal characteristics, in particular the influence of Mg content on deformation behaviors. Mg content has a pronounced effect on serration characteristics, including the serration type and amplitude; Mg content tends to weaken the spatial correlation of the propagative bands. Additionally, the serration amplitude linearly increases with the maximum PLC band strain; high Mg content generates a higher PLC band strain at a given serration amplitude compared with low Mg content. Mg content is found to be effective to enhance the serration amplitude, the maximum PLC band strain and also the amount of elastic shrinkage outside PLC bands.
基金supported by the National Natural Science Foundation of China (Nos. 51674166, U1902220)the National Key R&D Program of China (No. 2021YFB3701303)。
文摘Effects of Mg content on the microstructure and mechanical properties of low Zn-containing Al−xMg−3Zn−1Cu cast alloys(x=3−5,wt.%)were investigated.As Mg content increased in the as-cast alloys,the grains were refined due to enhanced growth restriction,and the formation ofη-Mg(AlZnCu)_(2) and S-Al_(2)CuMg phases was inhibited while the formation of T-Mg_(32)(AlZnCu)_(49 )phase was promoted when Mg content exceeded 4 wt.%.The increase of Mg content encumbered the solution kinetics by increasing the size of eutectic phase but accelerated and enhanced the age-hardening through expediting precipitation kinetics and elevating the number density of the precipitates.As Mg content increased,the yield strength and tensile strength of the as-cast,solution-treated and peak-aged alloys were severally improved,while the elongation of the alloys decreased.The tensile strength and elongation of the peak-aged Al−5Mg−3Zn−1Cu alloy exceed 500 MPa and 5%,respectively.Precipitation strengthening implemented by T′precipitates is the predominant strengthening mechanism in the peak-aged alloys and is enhanced by increasing Mg content.
基金supported by the National Natural Science Foundation of China(Nos.51801079,52001140)the National Funds Through FCT of Portugal–Fundacao para a Ciência e a Tecnologia,under a scientific contract of 2021.04115.CEECIND,and the Projects of UIDB/00285/2020,and LA/0112/2020。
文摘To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properties of the SLM-fabricated Al−Mg−Mn−Sc−Zr alloy were systematically investigated by density measurement,microstructure characterization,and tensile testing.The results revealed that dense samples could be obtained by adjusting the SLM process parameters.The alloy exhibited a fine equiaxed-columnar bimodal grain microstructure.The presence of primary Al3Sc andα-Al(Mn,Fe)Si particles contributed to the grain refinement of the alloy with an average grain size of 4.63μm.Upon aging treatment at 350°C for 2 h,the strength and elongation of the alloy were simultaneously improved due to the precipitation of Al3Sc nanoparticles and the formation of the 9R phase.This study demonstrates that the strength−plasticity trade-off of the aluminum alloy can be overcome by utilizing SLM technology and subsequent post-heat treatment to induce the formation of the long-period stacked ordered phase.
文摘The Mg content of Zn1-xMgxO film grown on A-sapphire substrates by plasma-assisted molecular beam epitaxy is measured by inductively coupled plasma (ICP) and electronic probe microanalysis (EPMA). A theoretical model for analyzing the difference in the Mg content between Zn-rich and Zn-deficient conditions in the growth process is established, and the mathematical relation between Mg content and the temperature of the Mg cell is formulated under Zn-rich condition. The formula derived is proven to be correct by experiments.
基金financially supported by Shandong Provincial Natural Science Foundation(No.ZR2023QE028)Dalian National Laboratory for Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(No.DNL202021)+1 种基金the National Key Research and Development Program of China(No.2024YFB3813800)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202041)
文摘N-type Mg_(3)Sb_(2)-based alloys have recently attracted considerable attention due to the high thermoelectric performance.However,the performance degradation occurs because of Mg loss at high temperature.Elemental Mg plays a significantly critical role in thermoelectric performance and thermal stability,where most studies on these compounds have thus far concentrated on the nominal Mg content which heavily depends on the fabrication methods,with few attentions devoted to the essential issue of actual Mg content,resulting in the unclear mechanism of improving their stability,severely limiting their practical applications in thermoelectric power generation.Here,we systematically analyzed the thermoelectric performance,thermal stability,and changed micro structures before and after in situ electronic thermoelectric performance measurement at 750 K,for n-type Mg_(3)Sb_(2)-based alloys with different Mg and Co content.It was found that elemental Mg and Co have a similar effect on adjusting the electron transport characteristic,and the peak values of power factor and ZT are up to 32.4μW cm^(-1)K^(-2)and 1.8,respectively.Thermal stability is more sensitive to the Mg content of material matrix than thermoelectric performance,and the effects of Mgpoor condition on thermal stability cannot be compensated via cationic Co doping.We also proved the route of Mg loss in experiments.By balancing Mg content and Co doping,the optimized sample showed good stability,in which it reduced only by 10%over 170 h of measurement at 750 K.Density functional theory calculation showed that the bonding strength of Co-Mg is stronger than MgMg,also explaining the enhanced thermal stability.
基金the High Technology Research and Development Program of China(No.2002A4336072)
文摘Mg-content cored-wire was used to desulphurize and spheroidize ductile iron melt in industrial experiments. The optimal feeding speed and suitable treatment temperature were determined in the experiments. And cored-wire method and pouring method were compared. Conclusions have been drawn that, under these conditions in the experiments, the optimal feeding speed is 15m/min, treatment temperature should be as low as possible, 1400-1450℃ generally; and cored-wire method can act more effective in ductile iron melt desulphurization and spheroid than pouring method.
基金supported financially by the Shenzhen Technology Innovation Plan(Nos.CXZZ20140731091722497 and CXZZ20140419114548507)the Shenzhen Basic Research Project(Nos.JCYJ20150529162228734,JCYJ20160407090231002,JCYJ20150625155931806 and JCYJ20160427100211076)The Thirteen Five National Key Research and Development Plan(No.2016YFC1102601)
文摘In the present study,the effect of Zn content on the microstructure and deformation behavior of the as-cast Mg-Zn-Y-Nd alloy has been investigated.The results showed that as Zn content increased,the volume fraction of secondary phases increased.Moreover,the phase transformation from W-phase to W-phase and I-phase occurred.In the as-cast state,W-phase exists as eutectic and large block form.When Zn content increases to 6 and 8%（wt%）,small I-phase could precipitate around W-phase particles.Additionally,the effect of Zn content on the tensile properties and deformation behavior varies with the testing temperature.At room temperature,the tensile strength increases with Zn content,whereas the elongation increases initially and then decreases.At 250℃,as Zn content increases,the tensile strength decreases initially and then increases slightly,whereas the elongation decreases.At 350℃,the elongation increases with Zn content,whereas the tensile strength decreases initially and then increases slightly.
基金the National Natural Science Foundation of China (50701011)Natural Science Foundation of Inner Mongolia, China (200711020703)Science and Technology Planned Project of Inner Mongolia, China (20050205)
文摘In order to improve the cyclic stability of La-Mg-Ni system （Ce2Ni7-type） alloy electrode, small amount of Co was added in La0.75Mg0.25Ni3.5 alloy. The effect of Co on electrochemical performance and microstructure of the alloys were investigated in detail. XRD results showed that the alloys had multiphase structure composed of （La, Mg）2Ni7, LaNi5 and small amount of LaNi2 phases. The discharge capacity of the alloys first increased and then decreased with increasing Co content. At a discharge current density of 900 mA/g, the HRD of the alloy electrodes increased from 81.3% （x=0） to 89.2 % （x=0.2）, and then reduced to 87.8 % （x=0.6）. After 60 charge/discharge cycles, the capacity retention rate of the alloys enhanced from 52.67% to 61.32%, and the capacity decay rate of the alloys decreased from 2.60 to 2.05 mAh/g per cycle with increasing Co content. The obtained results by XPS and XRD showed that the fundamental reasons for the capacity decay of the La-Mg-Ni system （Ce2Ni7-type） alloy electrodes were corrosion and oxidation as well as passivation of Mg and Lain alkaline solution.
基金Project(2002AA331050) supported by Hi-tech Research and Development Program of China project(0208) supported by Science and Technology Research of Ministry of Education of China
文摘By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu alloys were investigated. The results indicate that the constituents formed during casting alloys are main Al1.9CuMg4.1Si3.3,Al4(MnFe)3Si2 and Mg2Si, while pure Si is only present in the alloy containing lower magnesium content. Increasing Mg content leads to increasing the amount of Mg2Si, but decreasing the amount of Al1.9CuMg4.1Si3.3 and Al4(MnFe)3Si2. During the following homogenization process, Al1.9CuMg4.1Si3.3 is completely dissolved, Al4(MnFe)3Si2 and pure Si remain unchanged. After rolling and final heat treatment, the constituents in the alloys change no longer.
基金supported by the National Natural Science Foundation of China(Nos.20473077 and 61540071)the Project of Natural Science Research of High Education in Jiangsu Province(No.15KJD140002)+2 种基金the Fundamental Research Funds of Changzhou Science and Technology Bureau(No.CJ20160026)the Changzhou Modern Optoelectronic Technology Research Institute Funds(No.CZGY13)the Natural Science Funds of Changzhou Institute of Technology(No.YN1408)
文摘The doping content of Mg plays an important role in the crystalline structure and morphology properties of Zn_(1-x )Mg_xO thin films. Here,using radio-frequency magnetron sputtering method,we prepared Zn_(1-x )Mg_xO thin films on single crystalline Si(100) substrates with a series of x values. By means of X-ray diffraction(XRD) and scanning electron microscope(SEM),the crystalline structure and morphology of Zn_(1-x )Mg_xO thin films with different x values are investigated. The crystalline structure of Zn_(1-x )Mg_xO thin film is single phase with x<0.3,while there is phase separation phenomenon with x>0.3,and hexagonal and cubic structures will coexist in Zn_(1-x )Mg_xO thin films with higher x values. Especially with lower x values,a shoulder peak of 35.1° appearing in the XRD pattern indicates a double-crystalline structure of Zn_(1-x )Mg_xO thin film. The crystalline quality has been improved and the inner stress has been released,after the Zn_(1-x )Mg_xO thin films were annealed at 600 °C in vacuum condition.
