Hydrogen storage properties of LaN4.25Al0.75 alloy were experimentally investigated by XRD, PC isotherm curves, hydrogen absorption kinetics curves, XPS and its particle diameter. The structure of unit cell of LaNi4.2...Hydrogen storage properties of LaN4.25Al0.75 alloy were experimentally investigated by XRD, PC isotherm curves, hydrogen absorption kinetics curves, XPS and its particle diameter. The structure of unit cell of LaNi4.25Al0.75 alloy was deduced. The relationship between its structure and hydrogen storage performance of LaNi4.25Al0.75 alloy was analyzed. The results show that LaNi4.25Al0.75 alloy has rapid hydrogen absorption rate and good resistance to combustibility. It is also found that the function of the hydrogen absorption plateau pressure and temperature is ln peq=-4 820/T＋12.46, and the hydrogen absorption rate of the alloy decreases with increasing the temperature.展开更多
A comparative study was conducted by using solution combustion synthesis with three different doping routes(liquid-liquid(WL10), liquid-solid(WLNO) and solid-solid(WLO)) to produce nanoscale powders and further fabric...A comparative study was conducted by using solution combustion synthesis with three different doping routes(liquid-liquid(WL10), liquid-solid(WLNO) and solid-solid(WLO)) to produce nanoscale powders and further fabricate the ultrafine-grained W-1.0 wt.%La2O3 alloys by pressureless sintering. Compared with pure tungsten, W-1.0 wt.%La2O3 alloys exhibit ultrafine grains and excellent mechanical properties. After sintering, the average grain size of the WLO sample is larger than that of WL10 and WLNO samples;the microhardness values of WL10 and WLNO samples are similar but larger than the value of WLO sample. The optimized La2O3 particles are obtained in the WL10 sample after sintering at 1500 ℃ with the minimum mean size by comparing with WLNO and WLO samples, which are uniformly distributed either at grain boundaries or in the grain interior with the sizes of(57±29.7) and(27±13.1) nm, respectively. This study exhibits ultrafine microstructure and outperforming mechanical properties of the W-1.0 wt.%La2O3 alloy via the liquid-liquid doping route, as compared with conventionally-manufactured tungsten materials.展开更多
Cu-Ni alloy nanoparticles were prepared by a microwave combustion method with the molar ratios of CU2＋ to Ni2＋ as 3：7, 4：6, 5：5, 6：4 and 7：3. The as-prepared samples were characterized by XRD, HR-SEM, EDX and V...Cu-Ni alloy nanoparticles were prepared by a microwave combustion method with the molar ratios of CU2＋ to Ni2＋ as 3：7, 4：6, 5：5, 6：4 and 7：3. The as-prepared samples were characterized by XRD, HR-SEM, EDX and VSM. XRD and EDX analyses suggest the formation of pure alloy powders. The average crystallite sizes were found to be in the range of 21.56-33.25 nm. HR-SEM images show the clustered/agglomerated particle-like morphology structure. VSM results reveal that for low Ni content （CusNis, Cu6Ni4 and Cu7Ni3）, the system shows paramagnetic behaviors, whereas for high Ni content （Cu3Ni7 and Cu4Ni6）, it becomes ferromagnetic.展开更多
The C_(f)/Al composites were joined to the TC4 alloy via the laser-induced combustion joining method.The exothermic reaction of the interlayer provided the required energy for the joining process.By combining the theo...The C_(f)/Al composites were joined to the TC4 alloy via the laser-induced combustion joining method.The exothermic reaction of the interlayer provided the required energy for the joining process.By combining the theoretical calculation and experiment,the chemical composition of the Ni−Al−Zr interlayer was designed.The microstructure and mechanical properties of the joint were investigated.The results show that the addition of Zr slightly weakened the combustion reaction of exothermic interlayer but played a key role in the successful joining.Ni−Al−Zr interlayer reacted with substrates,forming a TiAl_(3)layer adjacent to TC4 alloy and NiAl_(3),Ni_(2)Al_(3)layers adjacent to the C_(f)/Al composites.Zr content dominated the microstructure and shear strength of the joint.When the Zr content was 5 wt.%under the joining pressure of 2 MPa,the joint had a maximum shear strength of 19.8 MPa.展开更多
Oxidation and burning behaviors were studied for CaO added AM50 Mg composites which were manufactured by conventional melting and casting processes without SF6 protective gas. CaO added AM50 Mg composites show the sta...Oxidation and burning behaviors were studied for CaO added AM50 Mg composites which were manufactured by conventional melting and casting processes without SF6 protective gas. CaO added AM50 Mg composites show the stable oxidation resistance, while AMS0 Mg alloys show the poor oxidation resistance. The effects of CaO addition on the burning resistance under ambient, nitrogen and dry air atmospheres were examined for CaO added AM50 Mg composites. With increasing CaO addition, the burning temperature increases under ambient, nitrogen and dry air atmospheres. The burning temperatures of small test specimen under all conditions greatly increase even by 0.3% CaO （mass fraction） addition into AM50 Mg alloys.展开更多
The application of hybrid vehicle is a practical technical solution to the energy shortage and the environmental pollution.The internal combustion engine(ICE)plays a key role in the development of the hybrid vehicle.B...The application of hybrid vehicle is a practical technical solution to the energy shortage and the environmental pollution.The internal combustion engine(ICE)plays a key role in the development of the hybrid vehicle.Based on the requirements of the hybrid vehicle and the characteristic of Atkinson cycle,a set of designing methods for the Atkinson cycle gasoline engine is presented through the analysis of the optimized matching for the compression ratio,valve timing and the combustion chamber.The designing method has been verified by the bench test and the results show that the fuel consumption can be improved by12%–15%with the reduction of the low speed torque by 10%,and the low fuel consumption region in the fuel map extends significantly with the rated power almost keeping constant.It may be of great reference for the development of hybrid vehicle technology in China.展开更多
基金Project (50276063) supported by the National Natural Science Foundation of China
文摘Hydrogen storage properties of LaN4.25Al0.75 alloy were experimentally investigated by XRD, PC isotherm curves, hydrogen absorption kinetics curves, XPS and its particle diameter. The structure of unit cell of LaNi4.25Al0.75 alloy was deduced. The relationship between its structure and hydrogen storage performance of LaNi4.25Al0.75 alloy was analyzed. The results show that LaNi4.25Al0.75 alloy has rapid hydrogen absorption rate and good resistance to combustibility. It is also found that the function of the hydrogen absorption plateau pressure and temperature is ln peq=-4 820/T＋12.46, and the hydrogen absorption rate of the alloy decreases with increasing the temperature.
基金Projects(2017YFB0306000,2017YFB0305600)supported by the National Key Research and Development Program of ChinaProjects(51774035,51604025,51574031,51574030,51574029,51604240)supported by the National Natural Science Foundation of China+2 种基金Project(2019JZZY010327)supported by the Shandong Key Research and Development Plan Project,ChinaProjects(2174079,2162027)supported by the Natural Science Foundation Program of Beijing,ChinaProjects(FRF-IDRY-19-025,FRF-TP-17-034A2,FRF-TP-19-015A3,FRF-IDRY-19-003C2)supported by the Fundamental Research Funds for the Central Universities of China。
文摘A comparative study was conducted by using solution combustion synthesis with three different doping routes(liquid-liquid(WL10), liquid-solid(WLNO) and solid-solid(WLO)) to produce nanoscale powders and further fabricate the ultrafine-grained W-1.0 wt.%La2O3 alloys by pressureless sintering. Compared with pure tungsten, W-1.0 wt.%La2O3 alloys exhibit ultrafine grains and excellent mechanical properties. After sintering, the average grain size of the WLO sample is larger than that of WL10 and WLNO samples;the microhardness values of WL10 and WLNO samples are similar but larger than the value of WLO sample. The optimized La2O3 particles are obtained in the WL10 sample after sintering at 1500 ℃ with the minimum mean size by comparing with WLNO and WLO samples, which are uniformly distributed either at grain boundaries or in the grain interior with the sizes of(57±29.7) and(27±13.1) nm, respectively. This study exhibits ultrafine microstructure and outperforming mechanical properties of the W-1.0 wt.%La2O3 alloy via the liquid-liquid doping route, as compared with conventionally-manufactured tungsten materials.
文摘Cu-Ni alloy nanoparticles were prepared by a microwave combustion method with the molar ratios of CU2＋ to Ni2＋ as 3：7, 4：6, 5：5, 6：4 and 7：3. The as-prepared samples were characterized by XRD, HR-SEM, EDX and VSM. XRD and EDX analyses suggest the formation of pure alloy powders. The average crystallite sizes were found to be in the range of 21.56-33.25 nm. HR-SEM images show the clustered/agglomerated particle-like morphology structure. VSM results reveal that for low Ni content （CusNis, Cu6Ni4 and Cu7Ni3）, the system shows paramagnetic behaviors, whereas for high Ni content （Cu3Ni7 and Cu4Ni6）, it becomes ferromagnetic.
基金the financial supports from the National Natural Science Foundation of China(Nos.51975149,51905055)the Natural Science Foundation of Chongqing,China(No.cstc2020jcyj-msxmX0115)the Fundamental Research Funds for the Central Universities Project,China(No.2020CDJ-LHZZ 086).
文摘The C_(f)/Al composites were joined to the TC4 alloy via the laser-induced combustion joining method.The exothermic reaction of the interlayer provided the required energy for the joining process.By combining the theoretical calculation and experiment,the chemical composition of the Ni−Al−Zr interlayer was designed.The microstructure and mechanical properties of the joint were investigated.The results show that the addition of Zr slightly weakened the combustion reaction of exothermic interlayer but played a key role in the successful joining.Ni−Al−Zr interlayer reacted with substrates,forming a TiAl_(3)layer adjacent to TC4 alloy and NiAl_(3),Ni_(2)Al_(3)layers adjacent to the C_(f)/Al composites.Zr content dominated the microstructure and shear strength of the joint.When the Zr content was 5 wt.%under the joining pressure of 2 MPa,the joint had a maximum shear strength of 19.8 MPa.
文摘Oxidation and burning behaviors were studied for CaO added AM50 Mg composites which were manufactured by conventional melting and casting processes without SF6 protective gas. CaO added AM50 Mg composites show the stable oxidation resistance, while AMS0 Mg alloys show the poor oxidation resistance. The effects of CaO addition on the burning resistance under ambient, nitrogen and dry air atmospheres were examined for CaO added AM50 Mg composites. With increasing CaO addition, the burning temperature increases under ambient, nitrogen and dry air atmospheres. The burning temperatures of small test specimen under all conditions greatly increase even by 0.3% CaO （mass fraction） addition into AM50 Mg alloys.
文摘The application of hybrid vehicle is a practical technical solution to the energy shortage and the environmental pollution.The internal combustion engine(ICE)plays a key role in the development of the hybrid vehicle.Based on the requirements of the hybrid vehicle and the characteristic of Atkinson cycle,a set of designing methods for the Atkinson cycle gasoline engine is presented through the analysis of the optimized matching for the compression ratio,valve timing and the combustion chamber.The designing method has been verified by the bench test and the results show that the fuel consumption can be improved by12%–15%with the reduction of the low speed torque by 10%,and the low fuel consumption region in the fuel map extends significantly with the rated power almost keeping constant.It may be of great reference for the development of hybrid vehicle technology in China.
