The effects of Sc content on the mechanical properties of Al-Sc alloys were investigated.The results show that the strengths of all the tested alloys with 0.1 wt.%,0.3 wt.%,and 0.4 wt.%Sc additions increase initially ...The effects of Sc content on the mechanical properties of Al-Sc alloys were investigated.The results show that the strengths of all the tested alloys with 0.1 wt.%,0.3 wt.%,and 0.4 wt.%Sc additions increase initially with an increase in annealing time,due to the increase in volume fraction and size and the decrease in particle interspacing of Al3Sc particles.After reaching peak values,the strengths of all the tested alloys start to decrease with increasing annealing time due to the coarsening and increase in particle interspacing of At3Sc particles.It has also been shown that the alloy with 0.3 wt.%Sc has a higher strength and a lower elongation than the alloys with 0.1 wt.%and 0.4 wt.%Sc.The increase in strength and the decrease in elongation of the alloy with 0.3 wt.%Sc are due to the smaller particle interspacing of Al3Sc particles,resulting in a strong inhibition of dislocation movement during deformation.展开更多
The microstructure,in-plane anisotropy,and magnetic properties of Fe-Ga thin films were investigated by X-ray diffraction analysis,vibrating sample magnetometer,and capacitive cantilever method.The in-plane induced an...The microstructure,in-plane anisotropy,and magnetic properties of Fe-Ga thin films were investigated by X-ray diffraction analysis,vibrating sample magnetometer,and capacitive cantilever method.The in-plane induced anisotropy is well formed by the applied magnetic field during sputtering,and the anisotropy field Hk decreases with the sputtering power increasing.The coercivity of Fe-Ga thin films decreases with increasing power when the sputtering power is less than 60 W and increases when the power is larger than 60 W.The magnetostriction of the thin films reaches 66 × 10-6 at the sputtering power of 60 W.Excellent Fe-Ga films,which exhibit good field sensitivity,low coercivity and high magnetostriction,have been fabricated at the power of 60 W,and they can be used as the materials of magnetostrictive transducers.展开更多
On the basis of a multi-length scale modeling, a mixture-averaged multi-component/multiphase micro- segregation model was proposed without pre-set function for the micro-scale solute profile. The model explains the ef...On the basis of a multi-length scale modeling, a mixture-averaged multi-component/multiphase micro- segregation model was proposed without pre-set function for the micro-scale solute profile. The model explains the effect of morphologies of solidifying phases and solid back diffusion （SBD） on segregation, and covers the two limiting solidification cases of Scheil and Lever-rule models. A commercial Thermo-Calc software package/database was linked to the algorithms via its TQ6-interface for instantaneous determination of the related thermodynamic data of the multi-component alloys. The influences of cooling rate and other parameters on the solidification path and micro-segregation behavior were numerically investigated by sample calculation of the ternary AI-Cu-Mg alloys. A parallel experimental investigation on AI-Cu-Si alloys solidified under different cooling conditions was conducted to validate the theoretical model. Reasonable agreements were gained between the predicted solidification paths and the measured results.展开更多
A new self-made additive of amidocyanogen-acetic salt was used in wet ball-grind technique （WBGT） for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was i...A new self-made additive of amidocyanogen-acetic salt was used in wet ball-grind technique （WBGT） for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was investigated in detail. It was found that the prepared electrode had perfect electrochemical performances, such as rapid activation, high capability, high-rate discharge （HRD） ability, and good stability. The first discharge capacitance at 0.2 C （throughout this study, n C rate means that the rated capacity of a hydrogen storage alloy （full capacity） is charged or discharged completely in 1/n h） reached 278 mAh·g^-1 and the discharge capacitance reached the maximum of 322 mAh·g^-1 only after two charge-discharge cycles. For the dry method, wet method, and WBGT, the high rate discharge （HRD） values （C5 c/C0.2c ratio） were approximately 0.59, 0.76, and 0.83, respectively. The stable discharge capacity at 3 C increased from 275 mAh·g^-1 （dry method）to 295 mAh·g^-1 （WBGT）.展开更多
目的观察40岁以上围绝经期和绝经后女性骨密度(bone mineral density,BMD)的变化并分析其相关危险因素。方法选取2017年8月至2018年3月在我院门诊进行体检的40岁以上女性,详细记录其病史、身高、体重,进行生化和内分泌测试,然后进行双能...目的观察40岁以上围绝经期和绝经后女性骨密度(bone mineral density,BMD)的变化并分析其相关危险因素。方法选取2017年8月至2018年3月在我院门诊进行体检的40岁以上女性,详细记录其病史、身高、体重,进行生化和内分泌测试,然后进行双能X射线吸收测定扫描。结果研究人群的平均年龄为46.65岁,平均体质量指数为26.23 kg/m^2。研究中骨量减少的患病率为38%,骨质疏松症的患病率为4%,低骨密度的患病率为42%。随着年龄的增加和绝经状态的增加,低骨密度妇女的比例也随之增加。在内分泌评估中,60%的人群出现维生素D摄入不足的情况,56.67%的人群患有甲状旁腺功能亢进,100%的人群出现甲状腺功能减退,75%的人群伴随着甲状腺功能亢进,同时骨密度较低。在慢性疾病中,发现83.33%的女性患有糖尿病,50%的女性患有高血压,50%的女性具有肝肾功能异常,50%的女性患有关节炎等风湿性疾病,同时骨密度较低。每天接受阳光照射时间少于1 h的女性中,48.65%的人骨密度较低。由于日常体力劳动的减少,BMD正常的女性比例从72.72%下降到46.15%。在多因素Logistic回归分析中,发现血清维生素D缺乏,体力劳动和阳光照射不足与低BMD显著相关。结论低BMD不是仅限于绝经后妇女的疾病,它在40岁以上的女性中普遍存在。展开更多
Diffusion behavior of Nb in elemental powder metallurgy high Nb containing TiAl alloys was investigated. The results show that Nb element dissolves into the matrix by diffusion. Pore nests are formed in situ after Nb ...Diffusion behavior of Nb in elemental powder metallurgy high Nb containing TiAl alloys was investigated. The results show that Nb element dissolves into the matrix by diffusion. Pore nests are formed in situ after Nb diffusion. With the increase in hot pressing temperature, the diffusion of Nb will be more sufficient, and the microstructure is more homogeneous. Nb element diffuses completely at 1400℃. Meanwhile, compression deformation and agglomeration phenomena of pores are observed in some pore nests. Hot isostatic pressing （HIP） treatment can only efficiently decrease but not eliminate porosity completely.展开更多
The effects of Pb addition on the mechanical properties,microstructure,crystal structure and fracture characters were investigated.It has been found that the room-temperature mechani-cal properties of TiAl based alloy...The effects of Pb addition on the mechanical properties,microstructure,crystal structure and fracture characters were investigated.It has been found that the room-temperature mechani-cal properties of TiAl based alloy can be improved by Pb addition,the reasons for which have been explained based on the changes in microstructure and fracture characters with Pb addition.展开更多
基金supported by the National Natural Science Foundation of China(Nos.50831007,50823006,and 50825102)the Natural Science Foundation of Hunan Province,China(No.07JJ3117)
文摘The effects of Sc content on the mechanical properties of Al-Sc alloys were investigated.The results show that the strengths of all the tested alloys with 0.1 wt.%,0.3 wt.%,and 0.4 wt.%Sc additions increase initially with an increase in annealing time,due to the increase in volume fraction and size and the decrease in particle interspacing of Al3Sc particles.After reaching peak values,the strengths of all the tested alloys start to decrease with increasing annealing time due to the coarsening and increase in particle interspacing of At3Sc particles.It has also been shown that the alloy with 0.3 wt.%Sc has a higher strength and a lower elongation than the alloys with 0.1 wt.%and 0.4 wt.%Sc.The increase in strength and the decrease in elongation of the alloy with 0.3 wt.%Sc are due to the smaller particle interspacing of Al3Sc particles,resulting in a strong inhibition of dislocation movement during deformation.
基金supported by the National Natural Science Foundation of China (Nos.50571034 and 50971056) and the State Key Laboratory of Powder Metallurgy,Central South University
文摘The microstructure,in-plane anisotropy,and magnetic properties of Fe-Ga thin films were investigated by X-ray diffraction analysis,vibrating sample magnetometer,and capacitive cantilever method.The in-plane induced anisotropy is well formed by the applied magnetic field during sputtering,and the anisotropy field Hk decreases with the sputtering power increasing.The coercivity of Fe-Ga thin films decreases with increasing power when the sputtering power is less than 60 W and increases when the power is larger than 60 W.The magnetostriction of the thin films reaches 66 × 10-6 at the sputtering power of 60 W.Excellent Fe-Ga films,which exhibit good field sensitivity,low coercivity and high magnetostriction,have been fabricated at the power of 60 W,and they can be used as the materials of magnetostrictive transducers.
基金supported by the Open Project of State Key Laboratory of Powder Metallurgy of Central South University (Grant No. 2008112042)the National Natural Science Foundation of China (Grant Nos. 51071062 and 50801019)Project 973 (Grant No. 2011CB610406)
文摘On the basis of a multi-length scale modeling, a mixture-averaged multi-component/multiphase micro- segregation model was proposed without pre-set function for the micro-scale solute profile. The model explains the effect of morphologies of solidifying phases and solid back diffusion （SBD） on segregation, and covers the two limiting solidification cases of Scheil and Lever-rule models. A commercial Thermo-Calc software package/database was linked to the algorithms via its TQ6-interface for instantaneous determination of the related thermodynamic data of the multi-component alloys. The influences of cooling rate and other parameters on the solidification path and micro-segregation behavior were numerically investigated by sample calculation of the ternary AI-Cu-Mg alloys. A parallel experimental investigation on AI-Cu-Si alloys solidified under different cooling conditions was conducted to validate the theoretical model. Reasonable agreements were gained between the predicted solidification paths and the measured results.
文摘A new self-made additive of amidocyanogen-acetic salt was used in wet ball-grind technique （WBGT） for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was investigated in detail. It was found that the prepared electrode had perfect electrochemical performances, such as rapid activation, high capability, high-rate discharge （HRD） ability, and good stability. The first discharge capacitance at 0.2 C （throughout this study, n C rate means that the rated capacity of a hydrogen storage alloy （full capacity） is charged or discharged completely in 1/n h） reached 278 mAh·g^-1 and the discharge capacitance reached the maximum of 322 mAh·g^-1 only after two charge-discharge cycles. For the dry method, wet method, and WBGT, the high rate discharge （HRD） values （C5 c/C0.2c ratio） were approximately 0.59, 0.76, and 0.83, respectively. The stable discharge capacity at 3 C increased from 275 mAh·g^-1 （dry method）to 295 mAh·g^-1 （WBGT）.
文摘目的观察40岁以上围绝经期和绝经后女性骨密度(bone mineral density,BMD)的变化并分析其相关危险因素。方法选取2017年8月至2018年3月在我院门诊进行体检的40岁以上女性,详细记录其病史、身高、体重,进行生化和内分泌测试,然后进行双能X射线吸收测定扫描。结果研究人群的平均年龄为46.65岁,平均体质量指数为26.23 kg/m^2。研究中骨量减少的患病率为38%,骨质疏松症的患病率为4%,低骨密度的患病率为42%。随着年龄的增加和绝经状态的增加,低骨密度妇女的比例也随之增加。在内分泌评估中,60%的人群出现维生素D摄入不足的情况,56.67%的人群患有甲状旁腺功能亢进,100%的人群出现甲状腺功能减退,75%的人群伴随着甲状腺功能亢进,同时骨密度较低。在慢性疾病中,发现83.33%的女性患有糖尿病,50%的女性患有高血压,50%的女性具有肝肾功能异常,50%的女性患有关节炎等风湿性疾病,同时骨密度较低。每天接受阳光照射时间少于1 h的女性中,48.65%的人骨密度较低。由于日常体力劳动的减少,BMD正常的女性比例从72.72%下降到46.15%。在多因素Logistic回归分析中,发现血清维生素D缺乏,体力劳动和阳光照射不足与低BMD显著相关。结论低BMD不是仅限于绝经后妇女的疾病,它在40岁以上的女性中普遍存在。
基金This work is financially supported by the Key Grant Project of Chinese Ministry of Education (No. 704008) and by the Program from New Century Excellent Talents in University, China (No. NCET-04-01017).
文摘Diffusion behavior of Nb in elemental powder metallurgy high Nb containing TiAl alloys was investigated. The results show that Nb element dissolves into the matrix by diffusion. Pore nests are formed in situ after Nb diffusion. With the increase in hot pressing temperature, the diffusion of Nb will be more sufficient, and the microstructure is more homogeneous. Nb element diffuses completely at 1400℃. Meanwhile, compression deformation and agglomeration phenomena of pores are observed in some pore nests. Hot isostatic pressing （HIP） treatment can only efficiently decrease but not eliminate porosity completely.
文摘The effects of Pb addition on the mechanical properties,microstructure,crystal structure and fracture characters were investigated.It has been found that the room-temperature mechani-cal properties of TiAl based alloy can be improved by Pb addition,the reasons for which have been explained based on the changes in microstructure and fracture characters with Pb addition.
