For the purpose of decreasing the applied limitation resulting from the anisotropic mechanical property of Al-Li alloy 2195, this study employed a complex heat treatment process, involving the pre-tension, thermo-infi...For the purpose of decreasing the applied limitation resulting from the anisotropic mechanical property of Al-Li alloy 2195, this study employed a complex heat treatment process, involving the pre-tension, thermo-infiltration of the rare earth element Ce, solution treatment, and artificial aging technology. The results indicate that the infiltration of rare earth element Ce benefits the abatement of anisotropy of Al-Li alloy 2195 sheet, in contrast with that of the normal heat treatment process. The gradient of the Vickers-hardness decreases at least 50% through the thickness, and the tensile strength in the rolling direction also increases significantly. If Ce was infiltrated into the alloy under the optimum pre-deformation, the yield strength （σ0.2） increased by 30 MPa while the tensile strength （σb） enhanced by 25 MPa compared to the rare earth free samples. Meanwhile, the fractography illustrated that the fracture surface of the sample became more desirable.展开更多
A series of stearates with different rare-earth ion were investigated as thermal stabilizers for rigid PVC at 180 ℃ in air. Their stabilizing efficiency was based on measuring the rate of dehydrochlorination. The res...A series of stearates with different rare-earth ion were investigated as thermal stabilizers for rigid PVC at 180 ℃ in air. Their stabilizing efficiency was based on measuring the rate of dehydrochlorination. The resulted revealed the higher stabilizing efficiency of the investigated rare-earth stearates as thermal stabilizers for rigid PVC compared with the thermal stabilizers for industry: calcium stearate, zinc stearate, butyl stannum mercaptide, phosphite esters, β-diketone and epoxidized sunflower oil. This was well illustrated by longer incubation period (T_S) values and lower rate of dehydrochlorination. The stable efficiency was affected by the nature of rare-earth element's individual electronic shell. The mechanism for the stabilizing effect of rare-earth stearates was proposed. The result was experimentally proved based on IR spectrum.展开更多
The influence of rare-earth elements,La,Ce,Pr,Nd,Sm,Eu,Gd,Dy,Ho,Er and Yb on the thermal stability of PdSi_(16.5) glass was studied systematically by means of DSC.All rare-earth elements,especially heavy ones,increase...The influence of rare-earth elements,La,Ce,Pr,Nd,Sm,Eu,Gd,Dy,Ho,Er and Yb on the thermal stability of PdSi_(16.5) glass was studied systematically by means of DSC.All rare-earth elements,especially heavy ones,increase obviously the thermal stability parameters,including T_θ(T_g ,T_x ,T_g),T_(rg) and ΔE etc.The crystallization temperatures T_(p1) and T_(p2) increase linearly with the lanthanide constriction increasing,but Eu shows an anomalous influence:Pd-Si-Eu metallic glass possesses the highest thermal stability and the lowest concentration limit of glass forming among Pd-Si-R glasses.展开更多
The ZrO2-Al2O3 ceramic composites were prepared by appropriate techniques with commercial ZrO2 and Al2O3 powders as raw materials and Y2O3 as stabilizer. The results indicate that with the introduction of Al2O3 into t...The ZrO2-Al2O3 ceramic composites were prepared by appropriate techniques with commercial ZrO2 and Al2O3 powders as raw materials and Y2O3 as stabilizer. The results indicate that with the introduction of Al2O3 into the ZrO2 matrix where the quantity of additive Y2O3 is 3.5% (mole fraction), the growth of ZrO2 grains is efficiently inhibited, which helps the ZrO2 grains exist in a metastable tetragonal manner; thus higher strength and toughness are acquired. When the content of alumina is 20% (mass fraction), the bending strength and fracture toughness of the composites are 676.7 MPa and 10 MPa·m1/2 respectively, the mechanical behaviors are close to those prepared with ZrO2 and Al2O3 powders synthesized through wet chemical approach. The mechanical behaviors of the composites are well improved owing to the dispersion toughening of alumina grains and phase transformation toughening of zirconia grains.展开更多
采用拉伸测试和透射电镜(TEM),研究了微量Ce对高Cu Mg比率的Al Cu Mg合金组织和耐热性能的影响。结果表明,添加0.20%Ce后,在室温到350℃测试范围内,合金的室温拉伸强度和高温耐热性能得到了提高。透射电镜分析表明,合金中的主要强化相为...采用拉伸测试和透射电镜(TEM),研究了微量Ce对高Cu Mg比率的Al Cu Mg合金组织和耐热性能的影响。结果表明,添加0.20%Ce后,在室温到350℃测试范围内,合金的室温拉伸强度和高温耐热性能得到了提高。透射电镜分析表明,合金中的主要强化相为{111}型Ω相和少量的θ′相,添加微量Ce能细化合金中的强化相,提高强化相的高温热稳定性。展开更多
基金Project supported by the National Key Laboratory of Precision Thermal Treatment , Harbin Institute of Technology(51471050105HK0101)
文摘For the purpose of decreasing the applied limitation resulting from the anisotropic mechanical property of Al-Li alloy 2195, this study employed a complex heat treatment process, involving the pre-tension, thermo-infiltration of the rare earth element Ce, solution treatment, and artificial aging technology. The results indicate that the infiltration of rare earth element Ce benefits the abatement of anisotropy of Al-Li alloy 2195 sheet, in contrast with that of the normal heat treatment process. The gradient of the Vickers-hardness decreases at least 50% through the thickness, and the tensile strength in the rolling direction also increases significantly. If Ce was infiltrated into the alloy under the optimum pre-deformation, the yield strength （σ0.2） increased by 30 MPa while the tensile strength （σb） enhanced by 25 MPa compared to the rare earth free samples. Meanwhile, the fractography illustrated that the fracture surface of the sample became more desirable.
文摘A series of stearates with different rare-earth ion were investigated as thermal stabilizers for rigid PVC at 180 ℃ in air. Their stabilizing efficiency was based on measuring the rate of dehydrochlorination. The resulted revealed the higher stabilizing efficiency of the investigated rare-earth stearates as thermal stabilizers for rigid PVC compared with the thermal stabilizers for industry: calcium stearate, zinc stearate, butyl stannum mercaptide, phosphite esters, β-diketone and epoxidized sunflower oil. This was well illustrated by longer incubation period (T_S) values and lower rate of dehydrochlorination. The stable efficiency was affected by the nature of rare-earth element's individual electronic shell. The mechanism for the stabilizing effect of rare-earth stearates was proposed. The result was experimentally proved based on IR spectrum.
文摘The influence of rare-earth elements,La,Ce,Pr,Nd,Sm,Eu,Gd,Dy,Ho,Er and Yb on the thermal stability of PdSi_(16.5) glass was studied systematically by means of DSC.All rare-earth elements,especially heavy ones,increase obviously the thermal stability parameters,including T_θ(T_g ,T_x ,T_g),T_(rg) and ΔE etc.The crystallization temperatures T_(p1) and T_(p2) increase linearly with the lanthanide constriction increasing,but Eu shows an anomalous influence:Pd-Si-Eu metallic glass possesses the highest thermal stability and the lowest concentration limit of glass forming among Pd-Si-R glasses.
文摘The ZrO2-Al2O3 ceramic composites were prepared by appropriate techniques with commercial ZrO2 and Al2O3 powders as raw materials and Y2O3 as stabilizer. The results indicate that with the introduction of Al2O3 into the ZrO2 matrix where the quantity of additive Y2O3 is 3.5% (mole fraction), the growth of ZrO2 grains is efficiently inhibited, which helps the ZrO2 grains exist in a metastable tetragonal manner; thus higher strength and toughness are acquired. When the content of alumina is 20% (mass fraction), the bending strength and fracture toughness of the composites are 676.7 MPa and 10 MPa·m1/2 respectively, the mechanical behaviors are close to those prepared with ZrO2 and Al2O3 powders synthesized through wet chemical approach. The mechanical behaviors of the composites are well improved owing to the dispersion toughening of alumina grains and phase transformation toughening of zirconia grains.
文摘采用拉伸测试和透射电镜(TEM),研究了微量Ce对高Cu Mg比率的Al Cu Mg合金组织和耐热性能的影响。结果表明,添加0.20%Ce后,在室温到350℃测试范围内,合金的室温拉伸强度和高温耐热性能得到了提高。透射电镜分析表明,合金中的主要强化相为{111}型Ω相和少量的θ′相,添加微量Ce能细化合金中的强化相,提高强化相的高温热稳定性。
