Reaction between MgO-SiO2 refractory material and Fe-Al alloy

2018 ◽  
Vol 115 (5) ◽  
pp. 512 ◽  
Author(s):  
Abdulaziz Alhussein ◽  
Piotr R. Scheller ◽  
Wen Yang
Keyword(s):  
Refractory Material ◽  
Reaction Rate ◽  
Interface Layer ◽  
Al Alloy ◽  
Single Particles ◽  
Spinel Layer ◽  
Reduction Of Iron ◽  
Rate Controlling Step ◽  
High Frequency Induction Furnace ◽  
High Frequency Induction

The interaction between molten Fe-Al alloy containing 5.1 wt.% aluminium and MgO-SiO2-based refractory was investigated. In high-frequency induction furnace at 1550 °C refractory samples were immersed in liquid alloy for 1 min, 2 min, 10 min, 20 min, 30 min and 60 min. Scanning electron microscope was employed to investigate phases at the interface and inclusions in the Fe-Al alloy. Forsterite phase in refractory was transformed to MgO·Al2O3 spinel, owing to the reduction of iron oxide and silica in forsterite by aluminium in the Fe-Al alloy at the interface. The interface layer separated locally from the refractory material and formed cluster and single particles in the Fe-Al alloy. In view on the reaction rate, the disintegration of the refractory material increased the reaction area but interfered with increasing thickness of the spinel layer. The dissolution rate of silica into the molten alloy decreased with increasing the reaction time because of the slowed down transport of aluminium diffusing through increasing spinel layer became the rate controlling step.

Characterization of Mg-Al Sheet Clad Materials Fabricated by Hot Rolling

2007 ◽  
Vol 26-28 ◽  
pp. 409-412 ◽  
Author(s):  
Jae Seol Lee ◽  
Hyeon Taek Son ◽  
Ki Yong Lee ◽  
Soon Sub Park ◽  
Dae Guen Kim ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Vickers Hardness ◽  
Hot Rolling ◽  
High Strength ◽  
Interface Layer ◽  
Rolling Temperature ◽  
Al Alloy ◽  
Clad Sheet ◽  
The Difference ◽  
Interface Layers

AZ31 Mg / 5083 Al clad sheet was fabricated by the hot rolling method and its mechanical properties were investigated in this study. The tensile strength and yield strength of Mg- Al clad samples were slightly higher than that of AZ31 Mg sample, resulting in high strength 5083 Al alloy. Also, in the case of the AZ31 Mg sample, tensile strength indicated different values to the rolling directions. The thickness of interface layers between magnesium and aluminum materials increased with increasing rolling temperature. The thickness of interface layer was about 1.2 μm and 1.6 μm, respectively. The difference of thickness on the interface layer with variation of rolling temperature was attributed to promote the diffusion between magnesium and aluminum materials. The Vickers hardness of Mg-Al interface layer was around 125 Hv. The interface layer composed of hard inter-metallic phases which may act a increment of Vickers hardness depending upon its thickness.

Nucleation and growth of Al2O3/metal composites by oxidation of aluminum alloys

1991 ◽  
Vol 6 (9) ◽  
pp. 1964-1981 ◽  
Author(s):  
O. Salas ◽  
H. Ni ◽  
V. Jayaram ◽  
K.C. Vlach ◽  
C.G. Levi ◽  
...  
Keyword(s):  
Growth Process ◽  
Nucleation And Growth ◽  
Al Alloy ◽  
Oxide Growth ◽  
Spinel Layer ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
Continuous Formation ◽  
Initial Event ◽  
Al Composite

The nucleation and growth mechanisms during high temperature oxidation of liquid Al−3% Mg and Al−3% Mg−3% Si alloys were studied with the aim of enhancing our understanding of a new composite fabrication process. The typical oxidation sequence consists of an initial event of rapid but brief oxidation, followed by an incubation period of limited oxide growth after which bulk Al2O3/Al composite forms. A duplex oxide layer, MgO (upper) and MgAl2O4 (lower), forms on the alloy surface during initial oxidation and incubation. The spinel layer remains next to the liquid alloy during bulk oxide growth and is the eventual repository for most of the magnesium in the original alloy. Metal microchannels developed during incubation continuously supply alloy through the composite to the reaction interface. During the growth process, a layered structure exists at the upper extremity of the composite, consisting of MgO at the top surface, MgAl2O4 (probably discontinuous), Al alloy, and finally the bulk Al2O3 composite containing microchannels of the alloy. The bulk oxide growth mechanism appears to involve continuous formation and dissolution of the Mg-rich oxides at the surface, diffusion of oxygen through the underlying liquid metal, and epitaxial growth of Al2O3 on the existing composite body. The roles of Mg and Si in the composite growth process are discussed.

scholarly journals Comparing hydrogen absorption kinetics of the samples of intermetallic compound and metal hydride compact on its basis

2021 ◽  
Vol 2057 (1) ◽  
pp. 012043
Author(s):  
I A Romanov ◽  
V I Borzenko ◽  
A N Kazakov
Keyword(s):  
Intermetallic Compound ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Reaction Rate ◽  
Nickel Foam ◽  
High Confidence ◽  
Compact Sample ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Absorption Of Hydrogen

Abstract This work is devoted to an experimental study and comparison of the kinetics of hydrogen absorption by an intermetallic compound LaNi4.4Al0.3Fe0.3 in form of pure intermetallic compound free backfill and a compact based on it obtained by cold pressing with a spiral matrix of nickel-foam. To calculate the kinetic parameters of the hydrogen absorption reaction, the initial rates method is used. The PCT absorption isotherms are measured at temperatures of 313, 333, and 353 K. The experimental data are described with quite high confidence by the chosen model, which assumes that the reaction rate controlling step is the dissociative absorption of hydrogen on the surface of the a-phase. The rate of hydrogen absorption increases with increasing pressure drop and temperature. It is shown that the rate of hydrogen absorption by the sample of pure IMC is significantly less dependent on temperature compared to the compact sample. In addition, the reaction rate at temperatures of 313 and 333 K is higher for the free backfill sample, and at 353 K it is higher for the metal hydride compact. The values of the absorption constant and the activation energy of the hydrogen absorption reaction are determined for both samples.

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