In order to investigate the effects of Ce on mechanical anisotorpy of Al-Li alloys, the texture of 2090 Al-Li alloy with different Ce content was determined using orientation distribution function technique, in which the mechanical properties with different angles to rolling direction were measured. The effects of Ce on texture and mechanical properties of 2090 alloys were discussed. The results show that the type of main texture of 2090 alloys is 1225t <554>. Ce will not change the type of main texture of the alloy, but make the distribution of main texture scattered. Ce can change the volume fractions of ideal texture components and will decrease the anisotropy of yield strength, hence the content of the texture components that enhance the anisotropy of yield strength can be reduced.

This article describes for the first time the direct observation of the nucleation and growth process of closely packed silica nanowires via a vapor-liquid-solid (VLS) mechanism by using tin (Sn) as a catalyst. Initially, Sn particles formed alloy liquids, followed by the nucleation of short silica nanowires, and closely packed silica nanowires finally formed. Interestingly, our results indicated that Sn has different catalytic behavior for nanowire growth than commonly used metal catalysts such as Au and Fe. The structural features associated with different growth stages were monitored by SEM, TEM, EDX, and XPS analysis. A possible mechanism for the formation of closely packed silica nanowires is proposed.

The Dy and Ga substituted NdFeB nanocomposite permanent magnetic alloys with high magnetic properties have been prepared by appropriate wheel speed of melt-spinning and post-annealing treatment. Under optimal conditions, compared with the best magnetic properties of ternary NdFeB alloy of Jr=1∶18 T, Hci=379∶5kA=m and ðBHÞmax=119∶5 kJ=m3, the best magnetic properties of the alloy with Dy and Ga substitutions are Jr=1∶16 T, Hci=580∶5kA=m, and ðBHÞmax=162∶7kJ=m3. The XRD and TEM results showed that each of two alloys consists of hard magnetic 2∶14∶1 phase and soft magnetic a-Fe phase. The grain size of the 2∶14∶1 phase is about equal in the two alloys. The grain size and content of a-Fe phase in Dy and Ga substituted alloy are finer and lower, respectively. # 2002 Elsevier Science B.V. All rights reserved.

通过Co、Cu、Ga、Tb 联合添加，采用低温长时间细晶粒烧结技术，改善Nd-Fe-B烧结磁体的热稳定性，使其应用于电机磁钢。用SEM 电镜对显微组织进行分析，结果表明，添加Co、Cu、Ga、Tb 后晶粒大小均匀，形状规则化，富Nd 相厚度变薄，使反磁化核不易形成和扩展，从而提高Nd-Fe-B 磁体的矫顽力，改善磁体的热稳定性。

研究了经过不同热处理的NdFeB系纳米品复合永磁合金的磁滞行为。根据磁滞回线一阶导数曲线dM/dH～H分析了双相磁体磁滞回线M～H的变化情况。采用XRD和TEM对各典型回线对应的样品组织结构进行了观测分析，在欠时效和过时效条件下，dM/dH～日曲线均出现双峰，但对应不同的显微组织和不同的机制。在峰值时效条件下，合金由2∶14∶1和a-Fe双相组成，dM/dH～日曲线由单峰组成，磁滞回线表现为单相磁体的磁滞行为。