Al-Sc and Al-Ti semi-infinite targets were impacted by high-speed projectiles at velocities of 0.8, 1.0, 1.2 and 1.5 km/s, respectively. It is found that the Al-Sc targets demonstrate more excellent ability to resist ...Al-Sc and Al-Ti semi-infinite targets were impacted by high-speed projectiles at velocities of 0.8, 1.0, 1.2 and 1.5 km/s, respectively. It is found that the Al-Sc targets demonstrate more excellent ability to resist high-speed impact. It is concluded that different microstructures of Al-Sc and Al-Ti alloys, including different grain sizes and secondary particles precipitated in the matrix, result in their greatly different capabilities of resisting impact. Furthermore, the effect of the size range ofnanoscale A13Sc precipitate in A1-Sc alloy on the resistance of high-speed impact was investigated. In addition, computer simulations and validation of these simulations were developed which fairly accurately represented residual crater shapes/geometries. Validated computer simulations allowed representative extrapolations of impact craters well beyond the laboratory where melt and solidification occurred at the crater wall, especially for hypervelocity impact （〉5 km/s）.展开更多
Rapidly solidified Al-Ti base alloys were prepared by melt spinning at the cooling rate about 107 K/s. The melt-spun ribbons were used to observe the dricrostructures after heat treatment.In the supersaturated Al-Tl-S...Rapidly solidified Al-Ti base alloys were prepared by melt spinning at the cooling rate about 107 K/s. The melt-spun ribbons were used to observe the dricrostructures after heat treatment.In the supersaturated Al-Tl-Si alloy, age hardening occurred after 1 h anneal in the temperature range of 4000~500℃, which seems to be attributed to the precipitation of metastable Ll2- (Al,Si)3Ti phase. However. the microhardness was relatively low because of the low v/o and the insufflcient stability of precipitates. Thus. Cr was added to Al-Ti-Si alloys in order to stabilize the microstructures and to increase the v/o of precipitate5. As a result. the alIoys containing Cr were evaluated to possess the improved properties at the service temperature.展开更多
This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their appl...This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their applications as high-temperature wear resistant mechanical parts.Additionally,the wear mechanism of alloys is evaluated.The tribological properties of alloys are systematically studied by using a ball-on-disc tribometer at 10 N and 0.20 m/s from RT to 800°C sliding against Si3N4 ceramic ball.The boron element greatly improves the wear resistance of specimens as compared with that of unreinforced specimen.The friction coefficients of specimens decrease with increasing of testing temperature.The wear rates of Fe-Cr-B alloys decrease firstly and then raise with the increase of boron content.The specific wear rates of specimens with boron are 1/10 of the unreinforced specimen.Fe-21wt%Cr-7wt%B keeps the best tribological properties at high temperature.展开更多
The 40Bi2O3-30B2O3-(30-x)ZnO-xSrO (x=0-15mol%,BBZSr) glass system was prepared by the conventional melt quenching method.The effect of SrO addition on structure,thermal properties,chemical stability and sealing perfor...The 40Bi2O3-30B2O3-(30-x)ZnO-xSrO (x=0-15mol%,BBZSr) glass system was prepared by the conventional melt quenching method.The effect of SrO addition on structure,thermal properties,chemical stability and sealing performance of BBZSr glass were investigated thoroughly.The experimental results show that the total proportions of [BO3] group and [BO4] group decrease and the vibrations of [BiO3] group and [BiO6] group become weaker with the increase of SrO addition content,suggesting the glass network structure is strengthened owing to the SrO addition.Hence,both the thermal and chemical stability were significantly improved as the SrO content was increased.When the SrO content increased from 0 to 15mol%,the glass transition temperature and softening temperature slightly increased from 380 to 388 ℃ and from 392.7 to 402.2 ℃,respectively,meanwhile the coefficient of thermal expansion also increased from 10.49×10^-6 to 11.16×10^-6/℃ (30-300 ℃).The BBZSr glass with 15mol% SrO exhibited excellent comprehensive properties with low glass transition temperature(384.9 ℃),low softening temperature(400.3 ℃),high coefficient of thermal expansion (11.14×10^-6 ℃,30-300 ℃),good thermal and chemical stability.Besides,the glass had the good wetting behavior and sealing performance for Al-50%Si alloy.展开更多
mploying pure aluminum for address lines of TFT-LCDs has a severe problem of hillock formation at elevated temperature. However, in the case of large TFT-LCDs more than 254 mm, it is impossible to use refractory metal...mploying pure aluminum for address lines of TFT-LCDs has a severe problem of hillock formation at elevated temperature. However, in the case of large TFT-LCDs more than 254 mm, it is impossible to use refractory metals for address lines because of their high resistivity. The Al-Ti alloy films for address lines of TFT-LCDs were studied and it was found that Al-Ti alloy film has excellent resistance of Al-Ti alloy to hillocks. The effect of Ti content on properties of Al-Ti alloy film was investigated.展开更多
The electronic structure and ground state properties of TiX (X = Fe, Ni, Pd, Pt and Cu) type Shape Memory alloys have been calculated using the self consistent Tight- Binding Linear Muffin Tin Orbital (TB-LMTO) method...The electronic structure and ground state properties of TiX (X = Fe, Ni, Pd, Pt and Cu) type Shape Memory alloys have been calculated using the self consistent Tight- Binding Linear Muffin Tin Orbital (TB-LMTO) method. The systematic total energy studies made on TiX alloys in both B2 and (B19/B19’) structures successfully explain the structural stability of these compounds. The equilibrium lattice parameters, bulk moduli (Bo), cohesive energy (Ecoh) and heat of formation (ΔH) are calculated for these systems and compared with the available experimental and other theoretical results. The bonding nature of these TiX alloys is analyzed via the density of states (DOS) histogram.展开更多
Dry sliding wear behaviors of the Al 10Ti alloy prepared by mechanical alloying (MA) were investigated and compared with those of the alloy obtained by the rapid solidification (RS) process. The results show that, und...Dry sliding wear behaviors of the Al 10Ti alloy prepared by mechanical alloying (MA) were investigated and compared with those of the alloy obtained by the rapid solidification (RS) process. The results show that, under low sliding velocity of 0.66 m/s and low applied load, the predominant wear mechanism of Al 10Ti alloy against carbon steel is adhesion. The fine dispersing reinforcement in the alloy promotes the nucleation and propagation of cracks on the subsurface, leading to a higher wear rate of MA Al 10Ti alloy, compared with that of RS Al 10Ti alloy. With increasing normal load, the formation and spallation of transfer layers on the worn surface become the predominant wear mechanism. Therefore, the wear resistance of the alloy obtained by MA surpasses that achieved by RS due to the higher strength at both ambient and elevated temperature. The wear transfer layer of the MA Al 10Ti alloy is determined to be consisted mainly of Fe 2O 3 and metal Fe. [展开更多
Titanium is an excellent grain refiner for aluminium and aluminium alloys, and the addition is normal-ly made by melt inoculation with aluminium-titanium master alloys typically containing 2.5% and 5%titaniurn. The pa...Titanium is an excellent grain refiner for aluminium and aluminium alloys, and the addition is normal-ly made by melt inoculation with aluminium-titanium master alloys typically containing 2.5% and 5%titaniurn. The paper describes a process for the production of Al-2.5% Ti and Al-5% Ti master alloys by di-rect alloying of the metals, and presents the results obtained from the heats taken under different processconditions. Alloying efficiencies as high as 96%, computed on the basis of titanium recovery. have been ob-tained in the case of 2.5% Ti master alloy as against 900/0 for the 5% Ti master alloy, al operation temperatures of 1050℃ and 1200℃ respectively. The lower efficiency in the case of higher titanium master alloy isattributed to incomplete dissolution of titanium and the significant oxidation losses occurring at the highertemperature of operation.展开更多
文摘Al-Sc and Al-Ti semi-infinite targets were impacted by high-speed projectiles at velocities of 0.8, 1.0, 1.2 and 1.5 km/s, respectively. It is found that the Al-Sc targets demonstrate more excellent ability to resist high-speed impact. It is concluded that different microstructures of Al-Sc and Al-Ti alloys, including different grain sizes and secondary particles precipitated in the matrix, result in their greatly different capabilities of resisting impact. Furthermore, the effect of the size range ofnanoscale A13Sc precipitate in A1-Sc alloy on the resistance of high-speed impact was investigated. In addition, computer simulations and validation of these simulations were developed which fairly accurately represented residual crater shapes/geometries. Validated computer simulations allowed representative extrapolations of impact craters well beyond the laboratory where melt and solidification occurred at the crater wall, especially for hypervelocity impact （〉5 km/s）.
文摘Rapidly solidified Al-Ti base alloys were prepared by melt spinning at the cooling rate about 107 K/s. The melt-spun ribbons were used to observe the dricrostructures after heat treatment.In the supersaturated Al-Tl-Si alloy, age hardening occurred after 1 h anneal in the temperature range of 4000~500℃, which seems to be attributed to the precipitation of metastable Ll2- (Al,Si)3Ti phase. However. the microhardness was relatively low because of the low v/o and the insufflcient stability of precipitates. Thus. Cr was added to Al-Ti-Si alloys in order to stabilize the microstructures and to increase the v/o of precipitate5. As a result. the alIoys containing Cr were evaluated to possess the improved properties at the service temperature.
基金Projects(51775365,51405329) supported by the National Natural Science Foundation of ChinaProject(2015M570239) supported by the China Postdoctoral Science Foundation
文摘This work is aimed to study the effect of boron on wear resistance of Fe-Cr-B alloys containing different boron contents(0 wt%,5 wt%,7 wt%and 9 wt%)from room temperature(RT)to 800°C in order to explore their applications as high-temperature wear resistant mechanical parts.Additionally,the wear mechanism of alloys is evaluated.The tribological properties of alloys are systematically studied by using a ball-on-disc tribometer at 10 N and 0.20 m/s from RT to 800°C sliding against Si3N4 ceramic ball.The boron element greatly improves the wear resistance of specimens as compared with that of unreinforced specimen.The friction coefficients of specimens decrease with increasing of testing temperature.The wear rates of Fe-Cr-B alloys decrease firstly and then raise with the increase of boron content.The specific wear rates of specimens with boron are 1/10 of the unreinforced specimen.Fe-21wt%Cr-7wt%B keeps the best tribological properties at high temperature.
基金the Open Project Program of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(No.KLIFMD-2018-06)。
文摘The 40Bi2O3-30B2O3-(30-x)ZnO-xSrO (x=0-15mol%,BBZSr) glass system was prepared by the conventional melt quenching method.The effect of SrO addition on structure,thermal properties,chemical stability and sealing performance of BBZSr glass were investigated thoroughly.The experimental results show that the total proportions of [BO3] group and [BO4] group decrease and the vibrations of [BiO3] group and [BiO6] group become weaker with the increase of SrO addition content,suggesting the glass network structure is strengthened owing to the SrO addition.Hence,both the thermal and chemical stability were significantly improved as the SrO content was increased.When the SrO content increased from 0 to 15mol%,the glass transition temperature and softening temperature slightly increased from 380 to 388 ℃ and from 392.7 to 402.2 ℃,respectively,meanwhile the coefficient of thermal expansion also increased from 10.49×10^-6 to 11.16×10^-6/℃ (30-300 ℃).The BBZSr glass with 15mol% SrO exhibited excellent comprehensive properties with low glass transition temperature(384.9 ℃),low softening temperature(400.3 ℃),high coefficient of thermal expansion (11.14×10^-6 ℃,30-300 ℃),good thermal and chemical stability.Besides,the glass had the good wetting behavior and sealing performance for Al-50%Si alloy.
文摘mploying pure aluminum for address lines of TFT-LCDs has a severe problem of hillock formation at elevated temperature. However, in the case of large TFT-LCDs more than 254 mm, it is impossible to use refractory metals for address lines because of their high resistivity. The Al-Ti alloy films for address lines of TFT-LCDs were studied and it was found that Al-Ti alloy film has excellent resistance of Al-Ti alloy to hillocks. The effect of Ti content on properties of Al-Ti alloy film was investigated.
文摘The electronic structure and ground state properties of TiX (X = Fe, Ni, Pd, Pt and Cu) type Shape Memory alloys have been calculated using the self consistent Tight- Binding Linear Muffin Tin Orbital (TB-LMTO) method. The systematic total energy studies made on TiX alloys in both B2 and (B19/B19’) structures successfully explain the structural stability of these compounds. The equilibrium lattice parameters, bulk moduli (Bo), cohesive energy (Ecoh) and heat of formation (ΔH) are calculated for these systems and compared with the available experimental and other theoretical results. The bonding nature of these TiX alloys is analyzed via the density of states (DOS) histogram.
文摘Dry sliding wear behaviors of the Al 10Ti alloy prepared by mechanical alloying (MA) were investigated and compared with those of the alloy obtained by the rapid solidification (RS) process. The results show that, under low sliding velocity of 0.66 m/s and low applied load, the predominant wear mechanism of Al 10Ti alloy against carbon steel is adhesion. The fine dispersing reinforcement in the alloy promotes the nucleation and propagation of cracks on the subsurface, leading to a higher wear rate of MA Al 10Ti alloy, compared with that of RS Al 10Ti alloy. With increasing normal load, the formation and spallation of transfer layers on the worn surface become the predominant wear mechanism. Therefore, the wear resistance of the alloy obtained by MA surpasses that achieved by RS due to the higher strength at both ambient and elevated temperature. The wear transfer layer of the MA Al 10Ti alloy is determined to be consisted mainly of Fe 2O 3 and metal Fe. [
文摘Titanium is an excellent grain refiner for aluminium and aluminium alloys, and the addition is normal-ly made by melt inoculation with aluminium-titanium master alloys typically containing 2.5% and 5%titaniurn. The paper describes a process for the production of Al-2.5% Ti and Al-5% Ti master alloys by di-rect alloying of the metals, and presents the results obtained from the heats taken under different processconditions. Alloying efficiencies as high as 96%, computed on the basis of titanium recovery. have been ob-tained in the case of 2.5% Ti master alloy as against 900/0 for the 5% Ti master alloy, al operation temperatures of 1050℃ and 1200℃ respectively. The lower efficiency in the case of higher titanium master alloy isattributed to incomplete dissolution of titanium and the significant oxidation losses occurring at the highertemperature of operation.
