The characteristics of novel Nd-Fe （Ni, Co, Al ）-B microstructure prepared by strip casting technique were studied. The novel microstructure was observed using scanning electron microscope （SEM） and transmission e...The characteristics of novel Nd-Fe （Ni, Co, Al ）-B microstructure prepared by strip casting technique were studied. The novel microstructure was observed using scanning electron microscope （SEM） and transmission electron microscope （TEM）. Along the direction of heat flow, there are two kinds of different microstructures. Close to the wheel side, there is a thick layer containing many polygonal Nd2Fe14B grains. Near the free surface side, however, there are relative uniform platelike Nd2Fe14B grains whose growth direction is not completely the direction of the heat flow during solidification. The formation of the novel microstructure is presumed to be the contribution of the special temperature field and Ni component.展开更多
采用透射电子显微镜和正电子湮灭技术研究了低周疲劳过程中快凝Al Fe V Si Nd合金微结构的变化 ,发现 :经高载荷循环后晶内固溶元素析出产生偏聚体 ,且随循环次数的增加 ,偏聚体长大 ;当循环次数达到 15 0 0次后 ,随循环次数的继续增加 ...采用透射电子显微镜和正电子湮灭技术研究了低周疲劳过程中快凝Al Fe V Si Nd合金微结构的变化 ,发现 :经高载荷循环后晶内固溶元素析出产生偏聚体 ,且随循环次数的增加 ,偏聚体长大 ;当循环次数达到 15 0 0次后 ,随循环次数的继续增加 ,大于临界尺寸的偏聚体长大而小于临界尺寸的偏聚体重新溶解·展开更多
用DSC技术和M ssbauer谱研究了颗粒弥散的快凝Al Fe V Si Nd合金薄带中纳米相的转变和相变动力学·结果表明 :快凝Al Fe V Si Nd纳米合金在加热过程中亚稳的Al8Fe4Nd相向α Al13 (Fe ,V) 3 Si相转变 ,并用Avrami公式计算了Al8Fe4Nd...用DSC技术和M ssbauer谱研究了颗粒弥散的快凝Al Fe V Si Nd合金薄带中纳米相的转变和相变动力学·结果表明 :快凝Al Fe V Si Nd纳米合金在加热过程中亚稳的Al8Fe4Nd相向α Al13 (Fe ,V) 3 Si相转变 ,并用Avrami公式计算了Al8Fe4Nd相的分解激活能Eα 为 1 61± 0 1 2eV·研究表明亚稳相Al8Fe4Nd向α Al13 (Fe,V) 3 Si相转变的过程是由原子体扩散和原位扩散共同控制的·展开更多
A rapidly solidified Al_(85)Y_4Nd_4Fe_7 (%, in nominal atomic fraction) alloy was prepared by melt spinning. As-quenched and as-annealed microstructures were studied by differential scanning calorimetry (DSC), X-ray d...A rapidly solidified Al_(85)Y_4Nd_4Fe_7 (%, in nominal atomic fraction) alloy was prepared by melt spinning. As-quenched and as-annealed microstructures were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Fully amorphous structure could be obtained in the rapidly solidified Al_(85)Y_4Nd_4Fe_7 alloy ribbons. The temperature of first crystallization exceeds 300 ℃. Crystallization of as-annealed Al_(85)Y_4Nd_4Fe_7 alloy is shown to occur in two stages: (1) primary crystallization of α-Al; (2) formation of Al_3Y, Al_(13)Fe_4 and unknown crystalline phases.展开更多
文摘The characteristics of novel Nd-Fe （Ni, Co, Al ）-B microstructure prepared by strip casting technique were studied. The novel microstructure was observed using scanning electron microscope （SEM） and transmission electron microscope （TEM）. Along the direction of heat flow, there are two kinds of different microstructures. Close to the wheel side, there is a thick layer containing many polygonal Nd2Fe14B grains. Near the free surface side, however, there are relative uniform platelike Nd2Fe14B grains whose growth direction is not completely the direction of the heat flow during solidification. The formation of the novel microstructure is presumed to be the contribution of the special temperature field and Ni component.
文摘采用透射电子显微镜和正电子湮灭技术研究了低周疲劳过程中快凝Al Fe V Si Nd合金微结构的变化 ,发现 :经高载荷循环后晶内固溶元素析出产生偏聚体 ,且随循环次数的增加 ,偏聚体长大 ;当循环次数达到 15 0 0次后 ,随循环次数的继续增加 ,大于临界尺寸的偏聚体长大而小于临界尺寸的偏聚体重新溶解·
文摘用DSC技术和M ssbauer谱研究了颗粒弥散的快凝Al Fe V Si Nd合金薄带中纳米相的转变和相变动力学·结果表明 :快凝Al Fe V Si Nd纳米合金在加热过程中亚稳的Al8Fe4Nd相向α Al13 (Fe ,V) 3 Si相转变 ,并用Avrami公式计算了Al8Fe4Nd相的分解激活能Eα 为 1 61± 0 1 2eV·研究表明亚稳相Al8Fe4Nd向α Al13 (Fe,V) 3 Si相转变的过程是由原子体扩散和原位扩散共同控制的·
基金Project supported by the Education Bureau of Anhui Province (2000JL172)
文摘A rapidly solidified Al_(85)Y_4Nd_4Fe_7 (%, in nominal atomic fraction) alloy was prepared by melt spinning. As-quenched and as-annealed microstructures were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Fully amorphous structure could be obtained in the rapidly solidified Al_(85)Y_4Nd_4Fe_7 alloy ribbons. The temperature of first crystallization exceeds 300 ℃. Crystallization of as-annealed Al_(85)Y_4Nd_4Fe_7 alloy is shown to occur in two stages: (1) primary crystallization of α-Al; (2) formation of Al_3Y, Al_(13)Fe_4 and unknown crystalline phases.
