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研究(La1-xTix)2MgNi8.25Co0.75(x=0、0.1、0.2)合金的微观结构与电化学性能。相测试结果显示:所有合金都是由(La,Mg)Ni3和LaNi52个主相所构成的,晶胞参数随着Ti的替代而逐渐减小,这是因为Ti的共价键半径(0.132 nm)小于La(0.169 nm)所引起的。电化学测试结果表明:所有的合金电极经过4次活化后都能够达到最大放电容量,且放电容量随着Ti含量的增加而减少,从x=0时的384.6 mAh/g降低到x=0.2时的321.9 mAh/g,合金电极的循环寿命则从x=0时的53.1%提高到x=0.2时的67.8%,合金在1 200 mA/g时的高倍率放电性能先从x=0时的59.3%升高到x=0.1时的66.5%,然后又降低到x=0.2时的63.1%。此外,电化学动力学也显示出先增大后减小的特点。造成以上电化学性能变化的原因是Ti的加入一方面起到了脱氢催化的作用,另一方面使合金表面形成了致密氧化层,虽然阻止了合金进一步的腐蚀,但也降低了合金电极的动力学性能。 相似文献
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镁基储氢材料以吸氢量大、资源丰富、价格低廉、质量轻和无污染而被认为是最有发展前途的固态储氢材料之一.本文从镁基储氢材料的研究历史及现状出发.对其分类及制备、研究进展等进行了综述,并对其广阔的发展前景进行了展望. 相似文献
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A new-type Mg2Si composite was prepared with Mg-9Al-1Zn (AZ91) alloy and vermiculite as raw materials by melt infiltration method. The results show that the microstructure of composite consists of a large amount of MgESi precipitates and a little amount of MgO embedded in α-Mg matrix. The Vickers hardness of the composite is obviously higher than that of matrix of AZ91 alloy. Moreover, the composite exhibits excellent compressive property. The ultimate compressive strength of the material is 290 MPa, the yield strength is 175 MPa, and the elongation is about 5%, which are higher than those of AZ91 alloy. 相似文献
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利用铜模铸造方法制备了Ti45Cu35Zr8Ni7Pd5合金圆棒。通过XRD、SEM和DSC等手段研究了合金的组织,讨论了合金的玻璃形成能力,测定了合金的力学性能。结果表明,直径为2mm的圆棒为单一金属玻璃相,3mm和4mm直径的圆棒由金属玻璃相和TiCu结晶相组成。直径为2mm的圆棒具有最高的压缩断裂强度(2160MPa)和最高的硬度(维氏硬度,5600MPa)。压缩强度和硬度随着圆棒直径的增加而降低,但变形能力增加。 相似文献
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Mg-6Al--4RE-0.4Mn (mass fraction, %, RE=Ce rich mischmetal) alloy was prepared by steel mould casting technique. Solid solution and artificial aging (T6) were carried out. The microstructure and mechanical properties of both as-cast and T6 treated alloys were investigated at room temperature and 423 K. It is found that the intermetallic compounds of the as-cast and T6 treated alloys were mainly composed of Al11RE3, Mg17Al12 and Al6REMn6. The Vickers hardness (Hv) of the as-cast alloy is 63 and it increases to 70 after T6 heat treatment. T6 heat treatment plays a slight role in the tensile properties at room temperature, but the yield strength and elongation of T6 state at 423 K are distinctly improved. The yield strength and elongation of the as-cast alloy at 423 K are 71 MPa and 18%, respectively, and the values increase after T6 heat treatment, which is attributed to Al11RE3, Mg17Al12 and Al6REMn6 precipitates that impede the dislocation movement and gliding of grain boundaries effectively. 相似文献