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1.
Grain refinement is critical for fabricating high-quality Al-Si casting components in the application of automobile and aerospace industries,while the well-known Si-poisoning effect makes it difficult.Nbbased refiners offer an effective method to refine Al-Si casting alloys,but their anti Si-poisoning capability is far from being understood.In this work,the grain refining mechanism and the anti Si-poisoning effect in the Al-10 Si/Al-5 Nb-B system were systematically investigated by combining transmission electron microscope,first-principles calculations,and thermodynamic calculations.It is revealed that NbB2provides the main nucleation site in the Al-10 Si ingot inoculated by 0.1 wt.%Nb Al-5 Nb-B refiner.The exposed Nb atoms on the(0001)NbB2and(1-100)NbB2surface can be substituted by Al to form(Al,Nb)B2intermedia layers.In addition,a layer of NbAl3-like compound(NbAl3')can cover the surface of NbB2with the orientation relation of(1-100)[11-20]NbB2//(110)[110]NbAl3'.Both of the(Al,Nb)B2and NbAl3'intermedia layers contribute to enhancing the nucleation potency of NbB2particles.These discoveries provide fundamental insight to the grain refining mechanism of the Nb-B based refiners for Al-Si casting alloys and are expected to guide the future development of stronger refiners for Al-Si casting alloys. 相似文献
2.
《International Journal of Hydrogen Energy》2022,47(36):16121-16131
Ammonia is considered as a promising hydrogen or energy carrier. Ammonia absorption or adsorption is an important aspect for both ammonia removal, storage and separation applications. To these ends, a wide range of solid and liquid sorbents have been investigated. Among these, the deep eutectic solvent (DES) is emerging as a promising class of ammonia absorbers. Herein, we report a novel type of DES, i.e., metal-containing DESs for ammonia absorption. Specifically, the NH3 absorption capacity is enhanced by ca. 18.1–36.9% when a small amount of metal chlorides, such as MgCl2, MnCl2 etc., are added into a DES composed of resorcinol (Res) and ethylene glycol (EG). To our knowledge, the MgCl2/Res/EG (0.1:1:2) DES outperforms most of the reported DESs. The excellent NH3 absorption performances of metal–containing DESs have been attributed to the synergy of Lewis acid–base and hydrogen bonding interactions. Additionally, good reversibility and high NH3/CO2 selectivity are achieved over the MgCl2/Res/EG (0.1:1:2) DES, which enables it to be a potential NH3 absorber for further investigations. 相似文献
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Rotating-bending uniaxial fatigue tests and micro-fatigue crack initiation tests were carried out using a permanent mold cast
(PMC) and semi-solid die cast (SDC) with Al−7%Si−0.35%Mg composition in order to examine the relationship between solidification
structures and fatigue behaviors. The crack length was measured using a replication method. Fatigue strength was improved
in SDC, which was almost consistent with the predicted fatigue strength using the size of Si particle cluster. Resistance
to fatigue crack initiation and fatigue strength were improved in SDC owing to the finer Si cluster and to higher ultimate
tensile strength. Fatigue crack in PMC was preferentially initiated at pores. For SDC, the fatigue crack was initiated at
the Si particle/matrix interface, and then sucessively grew along eutectic cell boundaries. 相似文献
6.
采用实验的方法获得了氯酸锂共晶盐的蓄放冷特性的实用关系式。这种介质的融点为8℃,单位体积蓄冷量比冰大30%,适于用作空调系统中的蓄冷材料。 相似文献
7.
V. G. Khoruzhaya K. E. Kornienko P. S. Martsenyuk T. Ya. Velikanova 《Powder Metallurgy and Metal Ceramics》2006,45(5-6):251-258
Methods of differential thermal analysis, x-ray diffraction, microstructural analysis and electron probe microanalysis are
used to study alloys of the Al-Rh system over the whole concentration range. It is established that the phase of equiatomic
composition AlRh melts congruently at 2060°C and it has an extended range of homogeneity (45.1–54.2 at.% Rh). The solubility
of aluminum in rhodium reaches 9 at.%, decreasing to 6 at.% at 850°C. Coordinates are determined for the eutectic point l
⇆ AlRh + 〈Rh〉 as 70 at.% Rh and 1715°C. The existence of intermediate phases, their crystal structure, and also the method
of forming phases in the field of composition rich in aluminum given in publications are confirmed.
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Translated from Poroshkovaya Metallurgiya, Nos. 5–6(449), pp. 48–56, May–June, 2006. 相似文献
8.
V. Gaidarova 《Vacuum》2007,81(9):1082-1087
An investigation of the structure formation of as-cast Al-11 wt% Si (AlSi11) and Al-11 wt% Si-2 wt% Fe (AlSi11Fe2) rapidly solidified (RS) ribbons is performed. Ribbon samples are examined in detail using Auger electron spectroscopy (AES) and transmission electron microscopy (TEM). A nanoscale thickness layer of Si-precipitations, at both Al-grains boundary and oxide/Al-matrix interface, is found to be characteristic for “pure” AlSi11 ribbons. For Fe-doped ribbons, this layer comprises Fe-containing phase also, which appears to possess amorphous nature and is situated between the Si-grains and Al-matrix. A possible mechanism of altering the thermally activated volume diffusion of elements, due to the effect of Fe on the structure modification, is speculated based on the obtained results. 相似文献
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