Study on solid-state reactions of nanocrystalline TiAl synthesized by mechanical alloying

Forouzanmehr, Nazanin; Karimzadeh, F.; Enayati, M.H.

doi:10.1016/j.jallcom.2008.03.121

Cited by 53 publications

(27 citation statements)

References 15 publications

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“…Recently, MA has been widely used to synthesize nanocrystalline and amorphous SMAs [29][30][31], although limited investigations have been done on Fe-Mn-Si alloys.…”

Section: Introductionmentioning

confidence: 99%

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Phase transformation during mechano-synthesis of nanocrystalline/amorphous Fe–32Mn–6Si alloys

Amini

Shamsipoor

Ghaffari

et al. 2013

Materials Characterization

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Mechano-synthesis of Fe-32Mn-6Si alloy by mechanical alloying of the elemental powder mixtures was evaluated by running the ball milling process under an inert argon gas atmosphere. In order to characterize the as-milled powders, powder sampling was performed at predetermined intervals from 0.5 to 192 h. X-ray florescence analyzer, X-ray diffraction, scanning electron microscope, and high resolution transmission electron microscope were utilized to investigate the chemical composition, structural evolution, morphological changes, and microstructure of the as-milled powders, respectively.According to the results, the nanocrystalline Fe-Mn-Si alloys were completely synthesized after 48 h of milling. Moreover, the formation of a considerable amount of amorphous phase during the milling process was indicated by quantitative X-ray diffraction analysis as well as high resolution transmission electron microscopy image and its selected area diffraction pattern. It was found that the α-to-γ and subsequently the amorphous-to-crystalline (especially martensite) phase transformation occurred by milling development. © 2013 Elsevier Inc. All rights reserved. Keywords:Fe-Mn-Si shape memory alloys Mechanical alloyingPhase transformation Nanostructural/amorphous phase Microstructure IntroductionFe-Mn-Si alloys are a class of smart materials due to their suitable shape memory effect (SME), excellent machinability and formability, low cost, good weldability and corrosion resistance, and high strength having several industrial applications such as dampers, pipe couplings, big shape memory devices, hard metals or alloys joining, oxygen blowing nozzles and so on [1][2][3][4][5][6][7][8][9][10][11]. The production of stress induced martensite (ε, hcp) from parent austenite phase (γ, fcc) and the reverse transformation (γ to ε) during the heating cycle are the origins of SME in this alloying system [12][13][14][15][16][17][18]. This non-thermoelastic or semi-thermoelastic conversion occurred by the creation of stacking faults (SFs) due to the movement of the Shockley partial dislocations (a γ /6 <112>) in the parent phase. SFs are suitable sites for nucleation of the martensite phase; eventually, the ε-phase can be formed by their overlap [12,[17][18][19][20][21][22][23].Although induction melting under an argon gas atmosphere is widely utilized to produce Fe-based SMAs, solid-state routes such as mechanical alloying (MA) can be used to produce the alloys in the powder form [24]. During MA, by applying the high energy collision between ball and particles and consequently the repeated cold welding and fracture of the powders, not only is the alloying process attained but also the synthesis of the non-equilibrium structures such as supersaturated solid solutions, nanocrystalline and amorphous structures, and intermetallic compounds is possible [24][25][26][27][28].Recently, MA has been widely used to synthesize nanocrystalline and amorphous SMAs [29][30][31], although limited investigations have been done on Fe-Mn-Si alloys.

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“…Recently, MA has been widely used to synthesize nanocrystalline and amorphous SMAs [29][30][31], although limited investigations have been done on Fe-Mn-Si alloys.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, MA has been widely used to synthesize nanocrystalline and amorphous SMAs [29][30][31], although limited investigations have been done on Fe-Mn-Si alloys. To the best of our knowledge, the only work was done by Saito et al [24] in which the alloy system was fabricated by MA and its structure was evaluated qualitatively.…”

Section: Introductionmentioning

confidence: 99%

Phase transformation during mechano-synthesis of nanocrystalline/amorphous Fe–32Mn–6Si alloys

Amini

Shamsipoor

Ghaffari

et al. 2013

Materials Characterization

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“…The final MA product, after 32 h of milling, possessed a high microhardness value of 1150 HV, showing a significant enhancement on the atomized TiAl powder (850 HV) [15] and the ball-milled Ti-Al solid-solution powder without reinforcements (900 HV). [16] This improvement is attributed to further strengthening of the dispersed TiC nanoparticles within the Ti-Al solid-solution matrix having fine crystallite grains and remaining lattice strain (Fig. 3).…”

Section: Resultsmentioning

confidence: 99%

Structural Evolution during Reactive Mechanical Milling of TiC/Ti‐Al Nanocomposites

Shen

2009

Adv Eng Mater

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High-energy Mechanical Alloying (MA) has been used successfully to produce numerous equilibrium or nonequilibrium alloy phases starting from blended elemental or pre-alloyed powders. The non-equilibrium phases synthesized include supersaturated solid solutions, metastable crystalline and quasicrystalline phases, nanostructures, and amorphous alloys. [1][2][3] MA, as a non-equilibrium, low temperature, and solid-state powder treatment process, involves repeated cold-welding, fracturing, and re-welding of powder particles in a high-energy ball mill.Titanium aluminides (TiAl) are of great importance for intermediate-temperature (600 to 850 8C) aerospace and power-generation applications because they offer significant weight savings over today's nickel-based superalloys. [4] Furthermore, TiAl alloys possess a unique combination of high specific strength, high elastic modulus, and excellent antioxidation capabilities. [5] However, the limited roomtemperature ductility and the decreased high-temperature strength are the most-significant impediments to broadening their practical applications. [6] In order to improve their ductility, recent research efforts have focused on the preparation of ultrafine grained nanocrystalline TiAl. [7] On the other hand, the synthesis of ceramic reinforced TiAl-matrix nanocomposites is an important consideration in improving their high-temperature performance. In particular, the preparation of in situ particulate-reinforced nanocomposites is regarded as the most-promising method. [8] The ultrafine particulates that are formed in situ are thermally stable and possess coherent and compatible interfaces with the matrix, thereby assuring that the composite system has enough strength to transfer stress.MA provides us with an innovative process of the in situ preparation of ceramic-particulate-reinforced nanocomposites materials. Ultrafine, nanometer-scaled grain sizes coupled with a uniform distribution of the reinforcing phases are expected to improve the obtainable mechanical properties of composites prepared by the MA route. Nevertheless, MA is a complex process and accordingly involves a large degree of uncertainty in obtaining the desired phases and microstructures. Significant experimental research is still required to study how the phases, microstructures, and compositions of MA-processed powder are evolved during ball milling. A theoretical understanding of the formation mechanisms behind the microstructural development of milled powders is also regarded as necessary.In this work, TiC/Ti-Al nanocomposite powders were synthesized in situ by MA of a mixture consisting of elemental Ti, Al, and graphite powder, with a nominal composition of Ti 50 Al 25 C 25 . The phase, microstructure, and composition transformations of the milled powders were characterized and reasonable mechanisms for the powder formation during the reactive MA process are proposed. Results and DiscussionThe X-ray diffraction (XRD) spectra of the starting elemental-powder mixture and the milled powders at different MA ti...

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“…The formation of intermetallics from their elemental components accelerates during ball-milling to become a self-sustaining high temperature reaction [3,4]. Among intermetallic compounds, the titanium aluminide compounds (Ti 3 Al, TiAl and TiAl 3 ) are attractive candidate materials for aerospace structure and engine applications [5]. The advantages of these materials are their low density, high specific strength, and relatively good properties at elevated temperatures and high creep resistance [6,7].…”

Section: Introductionmentioning

confidence: 99%

Self-Consolidation and Surface Modification of Mechanical Alloyed Ti-25.0 at.% Al Powder Mixture by Using an Electro-Discharge Technique

Chang¹,

Jang²,

Yoon³

et al. 2017

Archives of Metallurgy and Materials

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Electrical discharges using a capacitance of 450 μF at 0.5, 1.0, and 1.5 kJ input energies were applied in a N 2 atmosphere to obtain the mechanical alloyed Ti 3 Al powder without applying any external pressure. A solid bulk of nanostructured Ti 3 Al was obtained as short as 160 μsec by the Electrical discharge. At the same time, the surface has been modified into the form of Ti and Al nitrides due to the diffusion process of nitrogen to the surface. The input energy was found to be the most important parameter to affect the formation of a solid core and surface chemistry of the compact.

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Study on solid-state reactions of nanocrystalline TiAl synthesized by mechanical alloying

Cited by 53 publications

References 15 publications

Phase transformation during mechano-synthesis of nanocrystalline/amorphous Fe–32Mn–6Si alloys

Phase transformation during mechano-synthesis of nanocrystalline/amorphous Fe–32Mn–6Si alloys

Structural Evolution during Reactive Mechanical Milling of TiC/Ti‐Al Nanocomposites

Self-Consolidation and Surface Modification of Mechanical Alloyed Ti-25.0 at.% Al Powder Mixture by Using an Electro-Discharge Technique

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