Probing the initial stage of synthesis of Al2O3/Al composites by directed oxidation of Al-Mg alloys

Venugopalan, H. S.; Tankala, K.; DebRoy, T.

doi:10.1007/bf02915075

Cited by 12 publications

(10 citation statements)

References 10 publications

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“…8,10,11 The results obtained with the MgO ceramics are in accordance with earlier reports, particularly in studies on composite materials, where MgO is used as the oxygen source or where Al-Mg is preferably oxidized. [33][34][35] These studies have shown that MgO cannot be in equilibrium with molten Al-alloys, especially in the presence of SiO 2 , unless in Mg excess (>9.98%). 33 Evaporation of Mg, causing continuous loss of Mg, has also been reported.…”

Section: Discussionmentioning

confidence: 97%

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Reactions at the Interface Between Al₂O₃–SiO₂ Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

2002

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The interfacial reactions between aluminosilicate ceramics doped with MgO, CaO, or BaO and Al-7 wt% Si alloy were investigated at 1023, 1173, and 1323 K under vacuum for 4 h. Alkaline-earth oxide additives defined phase formation and microstructure of the sintered ceramics and subsequently controlled the ceramic/metal interfacial reactions, which were always intensive. In general, reaction zones consisted of Al 2 O 3 , infiltrated with Al. In the case of CaO-and BaO-doped ceramics, precipitates formed into the metal phase and concentrated the reduced Ca and Ba, respectively. A reaction mechanism is proposed, which anticipates an active role of SiO 2 .

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Section: Discussionmentioning

confidence: 97%

“…33 Evaporation of Mg, causing continuous loss of Mg, has also been reported. 34 However, high Mg content can result in magnesium aluminates or spinels forms, which undergo less dissolution upon melt or slag attack. 31,33 …”

Section: Discussionmentioning

confidence: 99%

Reactions at the Interface Between Al₂O₃–SiO₂ Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

2002

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“…On heating to 850 ° C, the gap was filled by an oxidation layer that formed and then grew on the Al alloy surface. The sequence of the Al alloy oxidation in the gap has been discussed in detail elsewhere and is considered widely to occur through the following four steps: At low temperatures, Al oxidizes to form an Al 2 O 3 layer on the surface of the Al alloy and it grows in thickness with increasing temperature to 850°C. At higher temperatures, Mg in the Al alloy reduces Al 2 O 3 to Al and the free oxygen reacts with Mg to form a thin MgO layer. As the MgO grows on the surface of the Al alloy, the Mg activity in the Al alloy decreases and thus the relative Al concentration increases.…”

Section: Discussionmentioning

confidence: 99%

Interfacial Reactions Between Anorthite (CaAl₂Si₂O₈) and Al 7075 Alloy at 850°C and 1150°C

et al. 2016

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The present work reports an investigation of the interactions of Al 7075 alloy and anorthite at 850°C (150 h) and 1150°C (24 h). Transmission electron microscopy, electron probe microanalysis, X-ray diffraction, and scanning electron microscopy coupled with energy-dispersive spectroscopy were used to identify the mineralogical and microstructural changes at the metalceramic interface. At 850°C, the phase formation mechanisms were (

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“…In the cup test, the sequence of surface reactions of Al alloy (containing Mg and Zn) with air in the gap, as shown in Fig. (a), is believed to occur through the following steps: Al oxidizes to form an alumina layer on the surface of the alloy. This layer grows in thickness with increasing heating temperature to 850°C. Mg present in the alloy reduces alumina to form magnesia.…”

Section: Discussionmentioning

confidence: 99%

“…In the cup test, the sequence of surface reactions of Al alloy (containing Mg and Zn) with air in the gap, as shown in Fig. 8(a), is believed to occur through the following steps: [28][29][30][31][32][33][34] 1. Al oxidizes to form an alumina layer on the surface of the alloy.…”

Section: <50 Lm Thickness Interdiffusion Zone Chemically Closementioning

confidence: 99%

Interfacial Reactions Between BaAl₂Si₂O₈ and Molten Al Alloy at 850°C

et al. 2015

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A corrosion cup test was undertaken using BaAl 2 Si 2 O 8 and Al4.1Zn3.2Mg alloy, heated in air for 150 h at 850°C. Electron probe microanalysis, X-ray diffraction, and scanning electron microscopy coupled with energy dispersive spectroscopy were used to identify the mineralogical and microstructural changes at the interfaces. The microstructural results revealed three microstructural areas: (1) Spinel layer with large numbers of Al alloy channels; (2) interfacial area with mainly alumina, spinel, and BaAl 2 Si 2 O 8 ; and (3) interdiffusion zone chemically close to barium hexaaluminate. The principal observations are:1. BaAl 2 Si 2 O 8 was highly resistant to molten Al alloy corrosion owing to sluggish kinetics, as evidenced by the observation of unreacted BaAl 2 Si 2 O 8 grains in the interfacial area. 2. The nature of the microstructure, particularly an interdiffusion zone instead of a continuous layer of precipitated alumina at the interface between the Al alloy channels and the unreacted BaAl 2 Si 2 O 8 supports the conclusion that the corrosion mechanism is governed by interdiffusion (Si/Ba and Al/Mg) and substitution. 3. The formation and limited retention of an MgO layer at the metal-ceramic interface played a critical role in alloy oxidation and the consequent interfacial phenomena.

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Probing the initial stage of synthesis of Al2O3/Al composites by directed oxidation of Al-Mg alloys

Cited by 12 publications

References 10 publications

Reactions at the Interface Between Al₂O₃–SiO₂ Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

Reactions at the Interface Between Al₂O₃–SiO₂ Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

Interfacial Reactions Between Anorthite (CaAl₂Si₂O₈) and Al 7075 Alloy at 850°C and 1150°C

Interfacial Reactions Between BaAl₂Si₂O₈ and Molten Al Alloy at 850°C

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Probing the initial stage of synthesis of Al2O3/Al composites by directed oxidation of Al-Mg alloys

Cited by 12 publications

References 10 publications

Reactions at the Interface Between Al2O3–SiO2 Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

Reactions at the Interface Between Al2O3–SiO2 Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

Interfacial Reactions Between Anorthite (CaAl2Si2O8) and Al 7075 Alloy at 850°C and 1150°C

Interfacial Reactions Between BaAl2Si2O8 and Molten Al Alloy at 850°C

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Reactions at the Interface Between Al₂O₃–SiO₂ Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

Reactions at the Interface Between Al₂O₃–SiO₂ Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy

Interfacial Reactions Between Anorthite (CaAl₂Si₂O₈) and Al 7075 Alloy at 850°C and 1150°C

Interfacial Reactions Between BaAl₂Si₂O₈ and Molten Al Alloy at 850°C