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1.
用DTA法分析表明沉积法获得的非晶态Ni-P合金各特征温度的晶化激活能明显低于激冷法获得的非晶合金。在同一升温速率下,脉冲化学沉积层的初始晶化激活能和晶化起始温度Ton都高于化学沉积层,说明脉冲化学沉积层的热稳定性优于化学沉积层。 相似文献
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本文用低能离子束增强沉积技术室温下在Ni-Cr合金衬底上合成了YBCO超导膜缓冲层YSZ薄膜。XRD测试表明YSZ薄膜C轴对成取向;极力产测试表明薄膜平面织构强烈。 相似文献
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本文制备了一系列Al-Ni-RE (RE=La, Ce, Y) 非晶合金薄带, 利用差示量热扫描仪和X射线衍射仪考察了非晶合金的晶化行为和初生相, 并分析了其与合金成分和原子特性间的关系. 结果表明: 在拓扑不稳定参数λ以有效原子半径修正为λ'后, 每一Al-Ni-RE非晶合金体系可由其两个临界值划分为纳米晶、纳米玻璃和玻璃三类; Al-Ni-RE非晶合金的晶化开始温度和混合焓与λ'成良好的线性关系, 即λ'能很好的表征Al基非晶合金的热稳定性.
关键词:
Al基非晶
玻璃转变
初生相
热稳定性 相似文献
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本文采取在标样和试样中加入绝对量一致的内标元素控制的ICP-AES法,对合金中的多元组分进行同时测定。通过对Ag-Mg-Ni合金中Mg、Ni的分析研究和试样测定,获得较好的准确度、精密度,相对误差Mg<±0.5%,Ni<±3.0%,相对标准偏差均小于0.5%,能满足对合金分析的要求。适当调整称样量及待测溶液定容体积,可扩大测定范围。采用绝对量内标控制,大大减小了由称量和稀释溶液体积带入的误差,从而提高了分析的准确度和精密度 相似文献
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文章采用多体势,用分子动力学模拟研究了含有无序界面的Ni/Zr双层膜在等温退火下的自发非晶化过程.在原子尺度上首次观察到了Ni-Zr之间的互扩散和合金化,以及由此导致的从界面开始、由扩散控制的非晶化. 相似文献
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利用透射电镜研究了Zr65Al7.5Ni10Cu12.5Ag5非晶合金的Vickers压痕内微观结构的变化. 结果发现,压痕塑性变形诱导非晶合金发生了晶化,在压头棱角下面的区域内有尺寸大于1 μm的晶体析出. 选区电子衍射分析表明,该析出相是稳定的CuZr2或NiZr2四方晶体,而没有析出该非晶合金在加热过程中的初生相二十面体准晶相,说明非晶合金的机械稳定性与热稳定性是有区别的. 打压痕过程中的温度升高是可以忽略的,本工作进一步证实了塑性变形诱导非晶合金晶化的主要动力是粘性流动而非局部热效应.
关键词:
非晶合金
塑性变形
粘性流动
局部热效应 相似文献
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铀基非晶合金是非晶家族中的特殊成员,受限于铀元素的高活性与放射性特点,目前这类非晶材料的研究极不充分.本文结合非晶合金的最新发展动态简要介绍了铀基非晶发展历史,较系统地总结了本团队的最新铀基非晶研究工作:首先较详细地介绍了新型铀基非晶的制备技术、成分体系、形成规律与晶化行为,澄清了其形成机制与热稳定性;结合高分辨电镜分析展示了其微观结构特点;采用纳米压痕技术揭示了这类非晶的微纳力学性能;利用电化学测试方法评估了其耐腐蚀性能.这些结果丰富了非晶材料的内涵,有助于深化对非晶物理基础科学问题的理解,并推动新型铀合金材料的发展,为这种材料的潜在工程应用奠定了基础. 相似文献
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Formation of Fe-Nb-X (X=Zr, Ti) amorphous alloys from pure metal elements by mechanical alloying 总被引:1,自引:0,他引:1
Zhiyu XiaoCuiyong Tang Tungwai Leo NgaiChao Yang Yuanyuan Li 《Physica B: Condensed Matter》2012,407(2):258-262
Fe-based amorphous powders of Fe56Nb6Zr38 and Fe60Nb6Ti34 based on binary eutectic were prepared by mechanical alloying starting from mixtures of pure metal powders. The amorphization behavior and thermal stability were examined by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and differential scanning calorimetry. Results show that Fe56Nb6Zr38 alloy has a better glass forming ability and a relatively lower thermal stability comparing with Fe60Nb6Ti34 alloy. The prepared amorphous powders have homogeneous element distribution and no obvious contaminants coming from mechanical alloying. The synthesized amorphous powders offer the potential for consolidation to full density with desirable mechanical properties through the powder metallurgy methods. 相似文献
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G. E. Abrosimova A. S. Aronin I. I. Zver’kova A. F. Gurov Yu. V. Kir’yanov 《Physics of the Solid State》1998,40(1):8-13
Radiography, differential scanning calorimetry, luminescence and high-resolution electron microscopy are used to study the
production, nanocrystalline structure, stability, and microhardness of alloys from the Ni-Mo-B system containing from 27 at.
% to 31.5 at. % Mo and 10 at. % B. All studies of these alloys indicated that annealing at 600 °C leads to the creation of
a granular phase consisting of FCC nanocrystallites with average grain sizes of 15–25 nm, depending on the chemical composition
of the alloy. Annealing these nanocrystalline samples isothermally at a temperature of 600 °C has no appreciable effect on
the grain size. Structurally, the nanocrystalline phase consists of grains of an FCC solid solution of Mo and B in Ni, dispersed
in an amorphous matrix that isolates them from one another. The lattice parameters of the FCC nanocrystallites depend on the
alloy composition and the duration of their isothermal anneal. Within this latter time, molybdenum and boron atoms diffuse
from the FCC solid-solution lattice into the surrounding amorphous matrix. The stability of the nanocrystalline structure
is determined by the thermal stability of the amorphous matrix, whose crystallization temperature increases with the isothermal
annealing time due to enrichment by boron and molybdenum. As the structure forms, the alloy becomes harder as the nanocrystalline
grains grow in size. This relation between hardness and grain size, which is opposite to the Hall-Petch law, is explained
by hardening of the amorphous matrix due to changes in its chemical composition.
Fiz. Tverd. Tela (St. Petersburg) 40, 10–16 (January 1998) 相似文献
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非晶态合金在力学性能、耐磨耐蚀性、磁性等方面比传统晶态合金具有显著优势,是一类有优良应用前景的新型结构与功能材料.非晶态合金与氢相互作用可以产生很多有趣的物理化学现象和应用.本文从物理基础和材料应用两个方面评述非晶态合金和氢相互作用的研究进展,在物理基础研究方面,从氢在非晶态合金中的存在状态出发,讨论氢在非晶态合金中的溶解、分布、占位和扩散等相关物理问题,进而分析氢对非晶态合金的热稳定性、磁性、内耗、氢脆等的影响.在材料应用研究方面,对非晶态储氢合金、非晶态合金氢功能膜、吸氢改善非晶态合金的塑性和玻璃形成能力、氢致非晶化、利用非晶态合金制备纳米储氢材料等方面的研究进展进行评述.最后总结并展望有关非晶态合金与氢相互作用的研究和应用. 相似文献
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Jasmine Chia-hsin Shih Laure BourgeoisKiyonori Suzuki Jose S. Garitaonandia 《Journal of magnetism and magnetic materials》2006
In order to clarify the origin of the high thermal stability of the microstructure in bcc-Fe/amorphous two-phase nanocrystalline soft magnetic materials, we have investigated the changes in the magnetic and microstructural properties upon isothermal annealing at 898 K for an Fe89Zr7B3Cu1 alloy by means of transmission electron microscopy, Mössbauer spectroscopy and DC magnetometry. The mean grain size was found to remain almost unchanged at the early stage of annealing. However, rapid grain coarsening was evident at an annealing time of 7.2 ks where the intergranular amorphous phase begins to crystallize into Fe23Zr6. The grain growth process with a kinetic exponent of 1.6 is observed for the growth process beyond this annealing time, reflecting the disappearance of the intergranular amorphous phase. Our results confirm that the thermal stability of the bcc-Fe/amorphous two-phase nanocrystalline soft magnetic alloys is governed by the residual amorphous phase. 相似文献
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非晶态材料有着复杂的原子结构(短程有序、长程无序)和特殊的物理性质,其临界现象和相变问题一直受到学术界关注.非晶合金,又称为金属玻璃,是一种新型的非晶态材料,具有很高的强度和优异的弹性.从微观的角度来看,非晶合金可以看作是一个多粒子系统.临界现象的研究对认识和理解多粒子系统之间的相互作用有深刻的意义.本文主要讨论非晶合金中的临界现象,包括非晶合金从制备过程、微观结构到宏观的力学性能以及磁性方面存在的临界现象,并分析这些临界现象之间的内在联系,进而深入理解非晶合金的微观结构对其宏观性质的影响.这为认识非晶合金的形成本质,提高服役可靠性,探索具有实际应用价值的非晶合金提供理论依据. 相似文献
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This paper deals with amorphous structures in the laser cladding. ZL111 alloy is the substrate and Ni-Cr-Al alloy is sprayed on the substrate as the coating material. The coating is clad by a 5 kW transverse flow CO2 laser. The observation of SEM and TEM reveal that in the laser cladding there are amorphous structures of two different morphologies: one is space curved flake-like, and exists in the white web-like structures; the other is fir leaf-like, and exists in the grain-like structures. Differential thermal analysis (DTA) is used to semi-quantitatively determine the content of the amorphous structures. A relation is obtained between the content of amorphous structures and the dimensionless laser cladding parameter C. We also show the changes of the amorphous structures after annealing. 相似文献
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1 Introduction Lasercladdingprocessistodepositaprotectivelayerontoaworkpiece.Theapplicationoflasercladdingcanbeconsideredint?.. 相似文献
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We have measured the low temperature (from 50 mK up to 5 K) specific heat and thermal conductivity of an amorphous ZrNi superconducting alloy as sputtered and after annealing in the amorphous state. We observe after annealing a decrease of the specific heat anomaly below 0.5 K together with an increase of the thermal conductivity. These variations are in agreement with a decrease of the density of two-level systems (T.L.S.) due to the structural relaxation. 相似文献