共查询到16条相似文献,搜索用时 187 毫秒
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用X射线衍射法研究了(Fe_(0.1)Co_(0.55)Ni_(0.35))_78Si_8B_(14)金属玻璃在常压下及20kbar高压下晶化过程中的析出相及析出过程。结果表明在上述压力下晶化过程都分成两个阶段,分别对应于初级晶化和共晶晶化。在常压下,初级晶化时析出fcc-Co晶体,而共晶晶化对应着Ni_(31)Si_(12)和(FeCoNi)_3(SiB)相的析出。随着回火温度的增高或时间的延长,(FeCoNi)_3(SiB)相逐渐转变为(FeCoNi)_(23)B_6相。20kbar高压下的晶化析出过程与常压下不同的是:提高了晶化温度,在共晶晶化阶段出现了Co_2B相。此外,压力还阻止(FeCoNi)_(23)B_6相的形成。从热力学和动力学的角度讨论了压力对金属玻璃晶化过程的影响。 相似文献
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本文用高压下原位电阻测量法研究了3GPa以下(Fe0.1Co0.55Ni0.35)78Si8B14金属玻璃的晶化温度Tx,并用Kissinger法求得不同压力下金属玻璃的晶化激活能△Ex。测量结果表明,施加压力时这种合金的Tx并不是单调地、更不是线性地升高的,而是在上升的总趋势中还存在某些局部的转折。这和一些被广泛引用的结论是不同的。晶化激活能△Ex也随压力作类似趋势的变化。分析认为,压力促进晶化时的成核过程,而抑制晶核的扩散性长大。两者的综合作用是造成△Ex、从而也构成Tx非单调变化的原因。压力除了通过△Ex影响Tx以外,指数前因子的压力效应也可以使晶化温度产生重要的改变。
关键词: 相似文献
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在CO2激光功率为50—300W、扫描速度为20mm/s、激光散光斑为20mm照射条件下 ,诱导非 晶Fe735Cu1Nb3Si135B9带中发生结构重组,产生定量纳米α-F e(Si)晶相形成双相组织结构材料. 利用穆斯堡尔谱研究了非晶Fe735C u1Nb3Si135B9合金激光纳米化的 超精细结构. 实验结果表明,激光诱导非晶 Fe735Cu1Nb3Si135B 9纳米化后,其超精细磁场的分布随 着激光功率变 化由单峰向双峰变化,在高功率辐照时, 出现了双峰分布,并且峰位向高场移动. 高激光 功率辐照非晶Fe735Cu1Nb3Si135 sub>B9合金纳米晶化相有四种超精细结 构,即2个超精细磁场较小的初晶相和2个超精细磁场较大的纳米晶化相. 其中超精细磁场较 大(17—25MA/m)的α-Fe(Si)相为DO3结构.
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激光
纳米晶α-Fe(Si)
735Cu1Nb< sub>3Si135B9')" href="#">非晶Fe735Cu1Nb< sub>3Si135B9
超精细结构
超精细磁场 相似文献
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用X射线衍射照相、X射线衍射仪及透射电子显微镜分析了用液相淬火技术制备的La80Al20合金样品,结果表明样品是非晶态结构。差热分析(DTA)结果表明,非晶态样品的晶化温度Tcr为280℃左右,玻璃温度Tg为242℃左右。非晶态样品低温高压(流体静压法)试验结果表明:压力从0至4.77kbar,Tc从3.87K提高到4.18K。高压下,超导前的剩余电阻与常压下相比较有明显下降。非晶态样品经高温高压
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In the present paper, we report the Meyer-Neldel relation between the pre-exponential factor and activation energy of non-isothermal crystallization of Co66Si16B12Fe4Mo2 metallic glass. Differential scanning calorimeter (DSC) is employed to study the change in the above two kinetic parameters of the crystallization due to ionic irradiation at three different fluences with high-energy heavy ion; Ni11+ of 150 MeV. 相似文献
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U. Güntzel K. Westerholt S. Methfessel 《Journal of magnetism and magnetic materials》1983,38(3):294-300
We report on measurements of magnetic hysteresis loops and initial permeability of amorphous metals with composition Fe81.5B14.5Si4, Fe40Ni40B20, Fe39Ni39(SiB)20 and Co67Fe4Mo2(SiB)27 in the temperature range between 4.2 and 300 K. For one sample (Fe40Ni40B20) the coercive force and the permeability are only weakly temperature dependent. The other samples show an increase in the coercive force up to a factor 3 and a decrease of the permeability up to a factor 10 in the temperature range below 70 K. The results are discussed within the framework of the statistical potential theory for Bloch wall movements. 相似文献
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Amorphous-crystalline dual-layer structures resulting from metastable liquid phase separation in (Fe50Co25B15Si10)80Cu20 melt-spun ribbons 下载免费PDF全文
(Fe50Co25B15Si10)80Cu20 ribbons are prepared by using the single-roller melt-spinning method. A dual-layer structure consisting of a (Fe, Co)-rich amorphous phase and a Cu-rich crystalline phase forms due to metastable liquid phase separation before solidification. The magnetic hysteresis loops of the as-quenched and annealed samples are measured at room temperature. It is indicated that the coercivity of the ribbon is almost zero in the as-quenched state. The crystallization leads to the increase of coercivity and decrease of saturation magnetization. 相似文献
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We have measured the electrical resistance and magnetic susceptibility of the magnetic superconductor, YgCo7, at pressures up to 20 kbar and in magnetic fields up to 6T. We have found that pressure suppresses the magnetism resulting in a higher superconducting transition temperature and conclude that Y9Co7 is an itinerant ferromagnet, not a spin-glass. Pressure also sharpens the superconducting transition and increases the critical magnetic field, signifying that the long range ferromagnetic and superconducting order parameters co-exist but vary spatially. For pressures greater than 6 kbar, the magnetoresistance is always positive, further indicating the suppresion of magnetism by high pressure. 相似文献
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The magnetic contribution to the thermoelectric power was separated for the metallic glass Fe20Ni60B10Si10 which exhibits the ferro-paramagnetic transition at Tc = 455 K remarkably below the crystallization threshold Tx = 670 K. Results are compared with the predictions of the Kasuya theory. 相似文献