Structural evolution of mechanically alloyed nanocrystalline FeAl intermetallics

Shi, Hongwei; Guo, Deqiang; Ouyang, Yifang

doi:10.1016/j.jallcom.2007.01.079

Cited by 55 publications

(29 citation statements)

References 17 publications

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“…The disordered Fe(Al) solid solution is the product of the milling process in all the above-mentioned cases. A fully ordered FeAl phase obtained by MEA of Fe-50 at.% Al has been reported [8]. A metastable, nanocrystalline Fe-66 at.% Al solid solution, which is ferromagnetic at room temperature, was prepared from elemental powders by mechanical alloying using high-energy ball mill [9].…”

Section: Introductionmentioning

confidence: 99%

Phase transformation, structural evolution, and mechanical property of nanostructured feal as a result of mechanical alloying

Hegde

Surendranathan

2009

Powder Metall Met Ceram

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The objective of the work is to synthesize nanostructured FeAl alloy powder by mechanical alloying (MEA). The work concentrates on the synthesis, characterization, and structural and mechanical properties of the alloy. Nanostructured FeAl intermetallics are prepared directly by MEA in a highenergy ball mill. Milling is performed under toluene solution to avoid contamination from the milling media and atmosphere. Mixtures of elemental Fe and Al are progressively transformed into a partially disordered solid solution with an average composition of Fe-50 at.% Al. Phase transformation, structural changes, morphology, particle size measurement, and chemical composition during MEA are investigated by X ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). Vickers microhardness (VMH) indentation tests are performed on the powders. The XRD and SEM studies reveal the alloying of elemental powders as well as transition to nanostructured alloy; crystallite size of 18 nm is obtained after 28 h of milling. Expansion/contraction in lattice parameter accompanied by reduction in crystallite size occurs during transition to nanostructured alloy. Longer milling introduces ordering in the alloyed powders as proved by the presence of superlattice reflection. Elemental and alloyed phases coexist while hardness increases during MEA.

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Section: Introductionmentioning

confidence: 99%

Phase transformation, structural evolution, and mechanical property of nanostructured feal as a result of mechanical alloying

Hegde

Surendranathan

2009

Powder Metall Met Ceram

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“…Abhik et al (2008) found that it was possible to produce FeAl after 10 hours of milling with toluene as a PCA. Shi et al (2008) investigated the stages in which the alloy forms during the mechanical alloying process. They milled the powders for a total of 50 hours and found that initially the powder formed a solid solution of Al in Fe and as milling time increased, the phase changed to the B2 FeAl phase.…”

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confidence: 99%

Cold-spray coating of an Fe-40 at.% Al alloy with additions of ruthenium

Couperthwaite

Cornish

Mwamba

2016

J. South. Afr. Inst. Min. Metall.

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Previous work conducted by Mintek (Couperthwaite et al., 2013(Couperthwaite et al., , 2015 investigated the effect of precious metal additions on the structure, oxidation and corrosion properties of an Fe-40 at.% Al (FeAl) alloy. Initial work determined that additions of more than 0.5 at.% precious metal did not improve the oxidation and corrosion properties of the materials and in some cases even decreased the resistance to corrosion. Further work identified Pt and Ru as beneficial additions to the FeAl alloy. Four alloys were then produced by mechanical alloying and sintering (FeAl-0.2 at.% Pd, FeAl-0.2 at.% Ru, FeAl-0.5 at.% Ag, FeAl-0.5 at.% Pt). These alloys were all successfully produced by melting and casting and mechanical alloying sintering and it was found that the nonequilibrium processing greatly decreased the grain size of the materials compared to the ascast materials. It was found that the additions of Ru and Pt were still the most beneficial to the oxidation and corrosion properties, with Ru being considered the most beneficial.This report details the results from the initial spray testing work done with the FeAl-0.2 at.% Ru alloy powder produced by mechanical alloying. There are several options for powder coating onto substrates; thermalspray techniques, which include high-velocity oxy-fuel (HVOF) coating and plasma coating, or cold-spray (also known as supersonicspray) techniques. Cold-spray techniques have attracted a lot of interest lately and as a system is available at University of the Witwatersrand, it was decided to use cold spraying in the current work. This work was done to determine the effectiveness of cold-spray coating of these mechanically alloyed powders.The iron-aluminium system has attracted a large amount of research due to the fact that Fe-Al intermetallic compounds possess good mechanical properties, along with low density and low cost, as well as easy access to the raw materials (Ji et al., 2006;Montealegre et al., 2000). Arzhnikov et al. (2008) found that the Fe-Al alloys are promising, due to their good refractoriness, oxidation and corrosion resistance and good ductility at room temperature. In comparison to conventional alloys, Fe-Al alloys perform much better at higher temperatures, due to the stability of the Cold-spray coating of an Fe-40 at.% Al alloy with additions of ruthenium by R.A. Couperthwaite*, L.A. Cornish † ‡ and I.A. Mwamba* In previous work by the authors, it was established that additions of 0.2 at.% Ru to an Fe-40 at.% Al alloy improved the corrosion and oxidation resistance of the alloy. The alloy was produced by mechanical alloying and spark plasma sintering and the work showed that nonequilibrium processing was able to significantly refine the grain size of the material. The sintered material had a higher hardness than the as-cast material and the change in grain size did not significantly affect the oxidation and corrosion. In the present research, the mechanically alloyed powder was coated onto a mild steel substrate using cold-spray coating at ...

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“…3(b) also describes that the Fe and Al element is not reacted. Their diffraction peaks are still separated at the constant peak position in the XRD pattern [21,22]. After annealing at 600 o C, the diffraction peaks of Fe-Al coating slightly shift to lower angles and become broader.…”

Section: Characterizationmentioning

confidence: 99%