Hierarchical porous TiAl3 intermetallics synthesized by thermal explosion with a leachable space-holder material

Jiao, Xinyang; Wang, Xiaohong; Kang, Xueqin; Feng, Peizhong; Zhang, Laiqi; Wang, Jianzhong; Akhtar, Farid

doi:10.1016/j.matlet.2016.06.048

Cited by 27 publications

(7 citation statements)

References 16 publications

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“…Open‐cellular porous aluminides can be fabricated by a combined process of the combustion reactions and space holder method. [ 12–14 ] In this method, raw powders are mixed with space holder particles and are reacted, followed by the removal of the space holder particles. The porosity and pore morphology can be controlled by the amount and shape of the space holder particles.…”

Section: Introductionmentioning

confidence: 99%

In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al₃Ti Composites From Al–Ti–B₄C Powders

et al. 2021

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The combustion foaming behaviors to synthesize closed-cellular porous Al 3 Ti composites are observed in situ using X-ray radioscopy. The in situ observation of the thermal explosion (TE) mode foaming reveals that the combustion foaming process consists of six steps. The shape of the sample changes uniformly in the first three steps before the sample foams. First, the sample expands uniformly 1) gradual expansion) and maintains an almost constant volume for a fixed period 2) temporary steady state at a constant volume). During these stages, bubbles are not generated inside the sample. Subsequently, the sample shrinks uniformly 3) slight shrinkage). After these three steps, the bubbles are rapidly generated inside the sample 4) rapid foaming). Immediately after foaming, the sample shrinks drastically while bubbles are ruptured and combined 5) severe shrinkage and bubble coarsening). Finally, the sample solidifies as a porous metal 6) solidification). The sample fabricated under the self-propagating hightemperature synthesis (SHS) mode includes graded microstructures corresponding to steps (1)-(4). The microstructures of the samples foamed under the TE and SHS modes are characterized. These results are used for discussing the elementary reaction steps arising at steps (1)-(4).

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Section: Introductionmentioning

confidence: 99%

In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al₃Ti Composites From Al–Ti–B₄C Powders

et al. 2021

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“…Currently, there are two major approaches to this goal: application of chemically-inert space holders or chemical compounds working as in situ foaming agents. NaCl has been used as a space holder to form porous intermetallics such as TiAl [ 2 ], TiAl 3 [ 3 ] or FeAl [ 4 ]. According to Ismail et al, NiTi alloy foam was formed with the use of stearic acid and poly methyl methacrylate (PMMA) as space holders [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of FeAl Intermetallic Foams by Tartaric Acid-Assisted Self-Propagating High-Temperature Synthesis

2018

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Iron aluminides are intermetallics with interesting applications in porous form thanks to their mechanical and corrosion resistance properties. However, making porous forms of these materials is not easy due to their high melting points. We formed FeAl foams by elemental iron and aluminum powders sintering with tartaric acid additive. Tartaric acid worked as an in situ gas-releasing agent during the self-propagating high-temperature synthesis of FeAl intermetallic alloy, which was confirmed by X-ray diffraction measurements. The porosity of the formed foams was up to 36 ± 4%. In the core of the sample, the average equivalent circle diameter was found to be 47 ± 20 µm, while on the surface, it was 35 ± 16 µm; thus, the spread of the pore size was smaller than reported previously. To investigate functional applications of the formed FeAl foam, the pressure drop of air during penetration of the foam was examined. It was found that increased porosity of the material increased the flow of the air through the metallic foam.

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“…After formation of the massive, porous element, the NaCl is leached out and porosity is revealed. Following this approach, metallic foams made of Al [ 15 , 16 , 17 ], Cu [ 18 ], FeAl [ 19 ], Mg [ 20 , 21 ], Ti [ 22 ], Ti 5 Si 3 [ 23 ], TiAl [ 24 ], and TiAl 3 [ 25 ] have been obtained. Nevertheless, using sodium chloride as the space holder may bring some risks since, when the leaching out process is too long, potentially galvanic cells may be formed and corrosion may occur.…”

Section: Introductionmentioning

confidence: 99%

“…The major motivations of the use of the amino acids as gas releasing agents are the volume of the in situ produced gases ( Table 1 ) and the formation of gaseous nitrogen, diluting remaining gaseous products including carbon dioxide, and thus decreasing the chemical interaction between the formed sinter and produced gas. Moreover, amino acids as well as other organic compounds [ 32 , 33 , 34 ] work as mentioned gas releasing agent, but first they act as space holders in the same way as e.g., NaCl [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Amino Acids Aided Sintering for the Formation of Highly Porous FeAl Intermetallic Alloys

2017

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Fabrication of metallic foams by sintering metal powders mixed with thermally degradable compounds is of interest for numerous applications. Compounds releasing gaseous nitrogen, minimizing interactions between the formed gases and metallic foam by diluting other combustion products, were applied. Cysteine and phenylalanine, were used as gas releasing agents during the sintering of elemental Fe and Al powders in order to obtain metallic foams. Characterization was carried out by optical microscopy with image analysis, scanning electron microscopy with energy dispersive spectroscopy, and gas permeability tests. Porosity of the foams was up to 42 ± 3% and 46 ± 2% for sintering conducted with 5 wt % cysteine and phenylalanine, respectively. Chemical analyses of the formed foams revealed that the oxygen content was below 0.14 wt % and the carbon content was below 0.3 wt %. Therefore, no brittle phases could be formed that would spoil the mechanical stability of the FeAl intermetallic foams. The gas permeability tests revealed that only the foams formed in the presence of cysteine have enough interconnections between the pores, thanks to the improved air flow through the porous materials. The foams formed with cysteine can be applied as filters and industrial catalysts.

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Hierarchical porous TiAl3 intermetallics synthesized by thermal explosion with a leachable space-holder material

Cited by 27 publications

References 16 publications

In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al₃Ti Composites From Al–Ti–B₄C Powders

In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al₃Ti Composites From Al–Ti–B₄C Powders

Fabrication of FeAl Intermetallic Foams by Tartaric Acid-Assisted Self-Propagating High-Temperature Synthesis

Amino Acids Aided Sintering for the Formation of Highly Porous FeAl Intermetallic Alloys

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Hierarchical porous TiAl3 intermetallics synthesized by thermal explosion with a leachable space-holder material

Cited by 27 publications

References 16 publications

In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al3Ti Composites From Al–Ti–B4C Powders

In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al3Ti Composites From Al–Ti–B4C Powders

Fabrication of FeAl Intermetallic Foams by Tartaric Acid-Assisted Self-Propagating High-Temperature Synthesis

Amino Acids Aided Sintering for the Formation of Highly Porous FeAl Intermetallic Alloys

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In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al₃Ti Composites From Al–Ti–B₄C Powders

In Situ X‐Ray Observations and Microstructural Characterizations for Understanding Combustion Foaming and Reaction Processes to Synthesize Porous Al₃Ti Composites From Al–Ti–B₄C Powders