The growth behavior of the complex intermetallic compounds(IMCs)formed at the interface of Cu/SnPbInBiSb high entropy alloy solder joints was explored.The growth inhibition mechanism of the IMCs at the Cu/SnPbInBiSb s...The growth behavior of the complex intermetallic compounds(IMCs)formed at the interface of Cu/SnPbInBiSb high entropy alloy solder joints was explored.The growth inhibition mechanism of the IMCs at the Cu/SnPbInBiSb solid−liquid reaction interface was revealed.The results showed that the growth rate of the complex IMCs obviously decreased at the Cu/SnPbInBiSb solid−liquid reaction interface.The maximum average thickness of IMCs only reached up to 1.66μm after reflowing at 200℃for 10 min.The mechanism for the slow growth of the complex IMCs was analyzed into three aspects.Firstly,the high entropy of the liquid SnPbInBiSb alloy reduced the growth rate of the complex IMCs.Secondly,the distorted lattice of complex IMCs restrained the diffusion of Cu atoms.Lastly,the higher activation energy(40.9 kJ/mol)of Cu/SnPbInBiSb solid−liquid interfacial reaction essentially impeded the growth of the complex IMCs.展开更多
The effect of Si on the growth kinetics of intermetallic compounds during the reaction of solid iron and molten aluminum was investigated with a scanning electron microscope coupled with an energy dispersive X-ray spe...The effect of Si on the growth kinetics of intermetallic compounds during the reaction of solid iron and molten aluminum was investigated with a scanning electron microscope coupled with an energy dispersive X-ray spectroscope, and hot-dip aluminized experiments. The results show that the intermetallic layer is composed of major Fe2Al5 and minor FeAl3. The Al-Fe-Si ternary phase, rl/rg, is formed in the Fe2Al5 layer. The tongue-like morphology of the Fe2Als layer becomes less distinct and disappears finally as the content of Si in aluminum bath increases. Si in the bath improves the prohibiting ability to the growth of Fe2Als and FeAl3. When the contents of Si are 0, 0.5%, 1.0%, 1.5%, 2.0% and 3.0%, the activation energies of Fe2Al5 are evaluated to be 207, 186, 169, 168, 167 and 172 kJ/mol, respectively. The reduction of the activation energy might result from the lattice distortion caused by Si atom penetrating into the Fe2Al5 phase. When Si atom occupies the vacancy site, it blocks easy diffusion path and results in the disappearance of tongue-like morphology.展开更多
Effect of thermal stabilization on the microstructure and mechanical property of directionally solidified Ti-46Al-0.5W-0.5Si （mole fraction, %） alloy was investigated. The specimens were thermal stabilized for diffe...Effect of thermal stabilization on the microstructure and mechanical property of directionally solidified Ti-46Al-0.5W-0.5Si （mole fraction, %） alloy was investigated. The specimens were thermal stabilized for different time （t） and directionally solidified at a constant growth rate of 30 μm/s and temperature gradient of 20 K/mm. Dependencies of the primary dendritic spacing （λ1）, secondary dendritic spacing （λ2）, interlamellar spacing （λL） and microhardness （HV） on holding time were determined. The values of the λ1, λ2 and λL increase with the increase of t, and the value of HV decreases with the increase of t. The increase of t is helpful to obtain a good directional solidification structure. However, it reduces the mechanical property of the directionally solidified TiAl alloy. The optimized value of t is about 30 min.展开更多
Ni-45.5Al-9Mo （mole fraction,%） alloy was directionally solidified with a constant temperature gradient （GL=334 K/cm） and growth rates ranging from 2 to 300 μm/s using a Bridgman type crystal growing facility wit...Ni-45.5Al-9Mo （mole fraction,%） alloy was directionally solidified with a constant temperature gradient （GL=334 K/cm） and growth rates ranging from 2 to 300 μm/s using a Bridgman type crystal growing facility with liquid metal cooling （LMC） technique. The effect of growth rate （v） on the solidified microstructures such as rod spacing （λ）, rod size （d） and rod volume fraction was experimentally investigated. Two types of the solidified interfaces, planar and cellular, were identified. On the condition of both planar and cellular eutectic microstructures, the relationships between λ, d and v were given as： λv1/2=5.90 μm·μm1/2·s1/2 and dv1/2=2.18μm·μm1/2·s1/2, respectively. It was observed that the volume fraction of Mo phase could be adjusted in a certain range. The variation of phase volume fraction was attributed to undercooling increase and the growth characteristics of the individual constituent phases during the eutectic growth.展开更多
The microstructures and crystal growth directions of permanent mould casting（PMC） and directionally solidified（DS） Al-Cu alloys with different contents of Cu were investigated. Simultaneously, the effects of pouri...The microstructures and crystal growth directions of permanent mould casting（PMC） and directionally solidified（DS） Al-Cu alloys with different contents of Cu were investigated. Simultaneously, the effects of pouring temperature on the microstructure and crystal growth direction of permanent mould casting pure Al were also discussed. The results indicate that the α（Al） crystals in the pure Al do not always keep common columnar grains, but change from the columnar grains to columnar dendrites with developed arms as the pouring temperature rises. The growth direction also varies with the change of pouring temperature. Cu element has similar effects on the microstructures of the PMC and DS casting Al-Cu alloys and the α（Al） crystals gradually change from columnar crystals in turn to columnar dendrites and developed equiaxed dendrites as the Cu content increases. The crystal growth direction in the PMC alloys gradually approaches （110） orientation with increasing Cu content. But the resulting crystals with growth direction of （110） do not belong to feathery grains. There are also no feathery grains to form in all of the DS Al-Cu alloys.展开更多
[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were...[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were cultured under heavy metal stress including Cu2＋,Hg2＋,Pb2＋,Cd2＋ and Cr6＋ in different concentrations. Then the growth curves of the bacteria were determined to investigate the effects of exogenous heavy metals on the growth of the two kinds of bacteria. [Result] The proliferation of the two bacteria was inhibited at high concentrations of Hg2＋ and Cd2＋ respectively,and G＋ is more sensitive to them than G-; when the heavy metal concentration was 50 mg/L,the toxicity of the five kinds of heavy metals on the two bacteria was Hg2＋Cd2＋Cu2＋Cr6＋≈Pb2＋. [Conclusion] The research will provide a basis to explore the effects of heavy metal on environment and ecological system.展开更多
The growth situation and peroxidase （POD） of seedlings of two tomato cultivars were investigated under the stress of different concentrations of Cu^2＋ and Cd^2＋ . The toxicity differences of Cu^2＋ and Cd^2＋ to t...The growth situation and peroxidase （POD） of seedlings of two tomato cultivars were investigated under the stress of different concentrations of Cu^2＋ and Cd^2＋ . The toxicity differences of Cu^2＋ and Cd^2＋ to tomato seedlings and the corresponding differences between two tomato cultivars were observed through the stress trial with the ahove two heavy metal ions, The resubs showed that low concentration of Cu^2＋ and Cd^2＋ could promote the growth and could enhance the POD activity of tomato seedlings, while high concentratiun Cu^2＋ and Cd^2＋ could inhibit seedling growth and POD activity of tomato seedlings. Cd^2＋ functioned more obviously than that of Cu^2＋ , two tomato cultivars also presented difference in response to heavy metal stress.展开更多
基金supported by the National Natural Science Foundation of China (No.U2241223)the Heilongjiang Touyan Innovation Team Program,China (No.HITTY-20190013)the Fundamental Research Funds for the Central Universities,China (No.AUEA5770400622)。
文摘The growth behavior of the complex intermetallic compounds(IMCs)formed at the interface of Cu/SnPbInBiSb high entropy alloy solder joints was explored.The growth inhibition mechanism of the IMCs at the Cu/SnPbInBiSb solid−liquid reaction interface was revealed.The results showed that the growth rate of the complex IMCs obviously decreased at the Cu/SnPbInBiSb solid−liquid reaction interface.The maximum average thickness of IMCs only reached up to 1.66μm after reflowing at 200℃for 10 min.The mechanism for the slow growth of the complex IMCs was analyzed into three aspects.Firstly,the high entropy of the liquid SnPbInBiSb alloy reduced the growth rate of the complex IMCs.Secondly,the distorted lattice of complex IMCs restrained the diffusion of Cu atoms.Lastly,the higher activation energy(40.9 kJ/mol)of Cu/SnPbInBiSb solid−liquid interfacial reaction essentially impeded the growth of the complex IMCs.
基金Project (51071135) supported by the National Natural Science Foundation of ChinaProject (20114301110005) supported by the Ph. D.Programs Foundation of Ministry of Education of ChinaProject (10XZX15) supported by the Science Foundation of Xiangtan University,China
文摘The effect of Si on the growth kinetics of intermetallic compounds during the reaction of solid iron and molten aluminum was investigated with a scanning electron microscope coupled with an energy dispersive X-ray spectroscope, and hot-dip aluminized experiments. The results show that the intermetallic layer is composed of major Fe2Al5 and minor FeAl3. The Al-Fe-Si ternary phase, rl/rg, is formed in the Fe2Al5 layer. The tongue-like morphology of the Fe2Als layer becomes less distinct and disappears finally as the content of Si in aluminum bath increases. Si in the bath improves the prohibiting ability to the growth of Fe2Als and FeAl3. When the contents of Si are 0, 0.5%, 1.0%, 1.5%, 2.0% and 3.0%, the activation energies of Fe2Al5 are evaluated to be 207, 186, 169, 168, 167 and 172 kJ/mol, respectively. The reduction of the activation energy might result from the lattice distortion caused by Si atom penetrating into the Fe2Al5 phase. When Si atom occupies the vacancy site, it blocks easy diffusion path and results in the disappearance of tongue-like morphology.
基金Projects (50801019, 51071062, 50771041) supported by the National Natural Science Foundation of ChinaProject (2011CB605504) supported by the National Basic Research Program of China
文摘Effect of thermal stabilization on the microstructure and mechanical property of directionally solidified Ti-46Al-0.5W-0.5Si （mole fraction, %） alloy was investigated. The specimens were thermal stabilized for different time （t） and directionally solidified at a constant growth rate of 30 μm/s and temperature gradient of 20 K/mm. Dependencies of the primary dendritic spacing （λ1）, secondary dendritic spacing （λ2）, interlamellar spacing （λL） and microhardness （HV） on holding time were determined. The values of the λ1, λ2 and λL increase with the increase of t, and the value of HV decreases with the increase of t. The increase of t is helpful to obtain a good directional solidification structure. However, it reduces the mechanical property of the directionally solidified TiAl alloy. The optimized value of t is about 30 min.
基金Project (51074128) supported by the National Natural Science Foundation of ChinaProject (2007ZF53067) supported by the Aeronautical Science Foundation of China+1 种基金Project (2010JM6002) supported by the Natural Science Foundation of Shaanxi Province of ChinaProjec t(2012NCL004) supported by the Innovation Foundation of Inner Mongolia University of Science and Technology
文摘Ni-45.5Al-9Mo （mole fraction,%） alloy was directionally solidified with a constant temperature gradient （GL=334 K/cm） and growth rates ranging from 2 to 300 μm/s using a Bridgman type crystal growing facility with liquid metal cooling （LMC） technique. The effect of growth rate （v） on the solidified microstructures such as rod spacing （λ）, rod size （d） and rod volume fraction was experimentally investigated. Two types of the solidified interfaces, planar and cellular, were identified. On the condition of both planar and cellular eutectic microstructures, the relationships between λ, d and v were given as： λv1/2=5.90 μm·μm1/2·s1/2 and dv1/2=2.18μm·μm1/2·s1/2, respectively. It was observed that the volume fraction of Mo phase could be adjusted in a certain range. The variation of phase volume fraction was attributed to undercooling increase and the growth characteristics of the individual constituent phases during the eutectic growth.
基金Project(51061010)supported by the National Natural Science Foundation of ChinaProject(NCET-10-0023)supported by the Program for New Century Excellent Talents in University of ChinaProject(J201103)supported by the Program for Hongliu Outstanding Talents of Lanzhou University of Technology,China
文摘The microstructures and crystal growth directions of permanent mould casting（PMC） and directionally solidified（DS） Al-Cu alloys with different contents of Cu were investigated. Simultaneously, the effects of pouring temperature on the microstructure and crystal growth direction of permanent mould casting pure Al were also discussed. The results indicate that the α（Al） crystals in the pure Al do not always keep common columnar grains, but change from the columnar grains to columnar dendrites with developed arms as the pouring temperature rises. The growth direction also varies with the change of pouring temperature. Cu element has similar effects on the microstructures of the PMC and DS casting Al-Cu alloys and the α（Al） crystals gradually change from columnar crystals in turn to columnar dendrites and developed equiaxed dendrites as the Cu content increases. The crystal growth direction in the PMC alloys gradually approaches （110） orientation with increasing Cu content. But the resulting crystals with growth direction of （110） do not belong to feathery grains. There are also no feathery grains to form in all of the DS Al-Cu alloys.
基金Supported by Science Research Fund Project of Yunnan Provincial Education Department "Physiological Toxicity of Heavy Metal Stress on Several Microorganisms" (09Y0382)Yunnan Natural Science Foundation Project "Toxicity Mechanism of Three Aquatic Plants under Heavy Metal Pollution" (2008ZC161M)~~
文摘[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were cultured under heavy metal stress including Cu2＋,Hg2＋,Pb2＋,Cd2＋ and Cr6＋ in different concentrations. Then the growth curves of the bacteria were determined to investigate the effects of exogenous heavy metals on the growth of the two kinds of bacteria. [Result] The proliferation of the two bacteria was inhibited at high concentrations of Hg2＋ and Cd2＋ respectively,and G＋ is more sensitive to them than G-; when the heavy metal concentration was 50 mg/L,the toxicity of the five kinds of heavy metals on the two bacteria was Hg2＋Cd2＋Cu2＋Cr6＋≈Pb2＋. [Conclusion] The research will provide a basis to explore the effects of heavy metal on environment and ecological system.
文摘The growth situation and peroxidase （POD） of seedlings of two tomato cultivars were investigated under the stress of different concentrations of Cu^2＋ and Cd^2＋ . The toxicity differences of Cu^2＋ and Cd^2＋ to tomato seedlings and the corresponding differences between two tomato cultivars were observed through the stress trial with the ahove two heavy metal ions, The resubs showed that low concentration of Cu^2＋ and Cd^2＋ could promote the growth and could enhance the POD activity of tomato seedlings, while high concentratiun Cu^2＋ and Cd^2＋ could inhibit seedling growth and POD activity of tomato seedlings. Cd^2＋ functioned more obviously than that of Cu^2＋ , two tomato cultivars also presented difference in response to heavy metal stress.
