采用了固相反应法制备了(Bi1.9Li0.1)(Zn2/3Nb4/3-x Al x)O7介质陶瓷。研究了Li+替代Bi3+,Al3+替代Nb5+对Bi2(Zn1/3Nb2/3)2O7陶瓷烧结特性、相结构及介电性能的影响。结果表明:Li-Al共掺能显著降低BZN烧结温度,由1000℃降至920℃,能改...采用了固相反应法制备了(Bi1.9Li0.1)(Zn2/3Nb4/3-x Al x)O7介质陶瓷。研究了Li+替代Bi3+,Al3+替代Nb5+对Bi2(Zn1/3Nb2/3)2O7陶瓷烧结特性、相结构及介电性能的影响。结果表明:Li-Al共掺能显著降低BZN烧结温度,由1000℃降至920℃,能改善介电性能,并对介电常数温度系数具有调节作用。当Li+掺杂量为0.1 mol,Al3+掺杂量为0.2 mol时,在920℃温度烧结2 h获得最佳性能:εr=75.42,tgδ=1.67×10-3,αc=29.1×10-6。展开更多
研究了 Mg L i4Al和 Mg L i8Al合金的阻尼性能。结果表明 ,Mg- L i- Al合金的阻尼性能随锂含量的增多和温度的提高而明显增高。其中 Mg L i8Al合金的室温阻尼性能达到 Q- 1 =0 .0 1的高阻尼值。Mg L i8Al合金的阻尼明显大于Mg L i4Al合...研究了 Mg L i4Al和 Mg L i8Al合金的阻尼性能。结果表明 ,Mg- L i- Al合金的阻尼性能随锂含量的增多和温度的提高而明显增高。其中 Mg L i8Al合金的室温阻尼性能达到 Q- 1 =0 .0 1的高阻尼值。Mg L i8Al合金的阻尼明显大于Mg L i4Al合金的阻尼是由于 Mg L展开更多
Mg-xLi-Al alloys with Mn addition from 0.2% to 1.5 % by wt. were produced and studied. The density of the alloys is very low, between 1.21 g/cm3 and 1.64 g/cm3, while the microstructures change from single α-, (α+β...Mg-xLi-Al alloys with Mn addition from 0.2% to 1.5 % by wt. were produced and studied. The density of the alloys is very low, between 1.21 g/cm3 and 1.64 g/cm3, while the microstructures change from single α-, (α+β)-, to single β-phase with lithium content rising from 5 % to 22 % by wt. The main alloy studied was LA92 alloy with Mn addition. The results of the tensile tests show that the strength decreases with increasing lithium content, while the elongation increases sharply, and the UTS and YS rise by 26.8% and 22.7% respectively, when 0.5 % by wt. Mn is added. It is also known, by microstructure observation, SEM with EDS and X-ray analysis, that adding Mn can produce some new hard phases in the alloy, which may worsen the tensile properties.展开更多
A system study on aging behavior and the influence of heat treatment on mechanical property of Mg8LilAl and Mg11Li3Al alloys has been carried out. The results show that the alloys described above have apparent aging b...A system study on aging behavior and the influence of heat treatment on mechanical property of Mg8LilAl and Mg11Li3Al alloys has been carried out. The results show that the alloys described above have apparent aging behavior and over aging happens even at room temperature. θ (MgLi2Al) phase has been identified when hardness reaches aging peak. With the increase of aging temperature, the size of 8(MgLi2Al)phase becomes larger apparently and 0ver aging happens. Heat treatment can raise tensile strength of Mg8Li1Al and Mg11Li3Al alloys, but the elongation decreases greatly.展开更多
To control the superplastic flow and fracture and examine the variation in deformation energy,the stress and grain size of Mg-7.28Li-2.19Al-0.091Y alloy were obtained using tensile testing and microstructure quantific...To control the superplastic flow and fracture and examine the variation in deformation energy,the stress and grain size of Mg-7.28Li-2.19Al-0.091Y alloy were obtained using tensile testing and microstructure quantification,and new high temperature deformation energy models were established.Results show that the grain interior deformation energy increases with increasing the strain rate and decreases with increasing the temperature.The variation in the grain boundary deformation energy is opposite to that in the grain interior deformation energy.At a given temperature,critical cavity nucleation energy decreases with increasing strain rate and cavity nucleation becomes easy,whereas at a given strain rate,critical cavity nucleation energy increases with increasing temperature and cavity nucleation becomes difficult.The newly established models of the critical cavity nucleation radius and energy provide a way for predicting the initiation of microcrack and improving the service life of the forming parts.展开更多
文摘研究了 Mg L i4Al和 Mg L i8Al合金的阻尼性能。结果表明 ,Mg- L i- Al合金的阻尼性能随锂含量的增多和温度的提高而明显增高。其中 Mg L i8Al合金的室温阻尼性能达到 Q- 1 =0 .0 1的高阻尼值。Mg L i8Al合金的阻尼明显大于Mg L i4Al合金的阻尼是由于 Mg L
文摘Mg-xLi-Al alloys with Mn addition from 0.2% to 1.5 % by wt. were produced and studied. The density of the alloys is very low, between 1.21 g/cm3 and 1.64 g/cm3, while the microstructures change from single α-, (α+β)-, to single β-phase with lithium content rising from 5 % to 22 % by wt. The main alloy studied was LA92 alloy with Mn addition. The results of the tensile tests show that the strength decreases with increasing lithium content, while the elongation increases sharply, and the UTS and YS rise by 26.8% and 22.7% respectively, when 0.5 % by wt. Mn is added. It is also known, by microstructure observation, SEM with EDS and X-ray analysis, that adding Mn can produce some new hard phases in the alloy, which may worsen the tensile properties.
文摘A system study on aging behavior and the influence of heat treatment on mechanical property of Mg8LilAl and Mg11Li3Al alloys has been carried out. The results show that the alloys described above have apparent aging behavior and over aging happens even at room temperature. θ (MgLi2Al) phase has been identified when hardness reaches aging peak. With the increase of aging temperature, the size of 8(MgLi2Al)phase becomes larger apparently and 0ver aging happens. Heat treatment can raise tensile strength of Mg8Li1Al and Mg11Li3Al alloys, but the elongation decreases greatly.
基金Project(51334006)supported by the National Natural Science Foundation of China
文摘To control the superplastic flow and fracture and examine the variation in deformation energy,the stress and grain size of Mg-7.28Li-2.19Al-0.091Y alloy were obtained using tensile testing and microstructure quantification,and new high temperature deformation energy models were established.Results show that the grain interior deformation energy increases with increasing the strain rate and decreases with increasing the temperature.The variation in the grain boundary deformation energy is opposite to that in the grain interior deformation energy.At a given temperature,critical cavity nucleation energy decreases with increasing strain rate and cavity nucleation becomes easy,whereas at a given strain rate,critical cavity nucleation energy increases with increasing temperature and cavity nucleation becomes difficult.The newly established models of the critical cavity nucleation radius and energy provide a way for predicting the initiation of microcrack and improving the service life of the forming parts.
