The effect of processing variables on the structure and chemistry of Ti-aluminide based LMCS

Goda, D.J; Richards, N.L.; Caley, W. F.; Chaturvedi, M.C.

doi:10.1016/s0921-5093(01)01894-9

Cited by 40 publications

(18 citation statements)

References 10 publications

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“…Similar behavior has been attributed to the formation of pores during the synthesis of various aluminides from powder mixtures [31][32][33][34][35][36]. This is also in agreement with studies suggesting that the diffusion of aluminum atoms into titanium particles is the predominant mechanism governing the formation of titanium aluminides [21,22,[25][26][27]. The globular morphology of the TiAl 3 phase obtained in this study is quite similar to what Xu et al [29] observed for the TiAl 3 phase in diffusion couple experiments.…”

Section: Tisupporting

confidence: 91%

“…This observation has been explained on the basis of the higher diffusivity of aluminum ions in TiAl 3 in comparison with other aluminides, which in any case might be formed in small amounts [23]. Formation of TiAl 3 on the titanium side of the diffusion couple, together with the movement of markers, proved that aluminum is the dominant diffusing specie [4,21,22,[25][26][27]. However, diffusion of titanium has also been reported by some workers [28,29].…”

Section: Introductionmentioning

confidence: 90%

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Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Sina

Iyengar

2015

J Therm Anal Calorim

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The formation of titanium aluminides in Ti-Al elemental powder mixtures containing 25, 50 and 75 at.% Al, has been studied using differential scanning calorimetry (DSC). Phase evolution in the mixture was followed by heating the compacted samples up to 1273 K at 7.5 and 15 K min -1 . The cooled samples were characterized using X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy. The results showed that the primary combustion product in all the samples was TiAl 3 , and the combustion reaction occurred below the melting point of aluminum only in Ti-rich samples. In Alrich samples (75 at.% Al), TiAl 3 was obtained as a porous, single-phase product after combustion. In samples containing 25 and 50 at.% Al, the combustion reaction was incomplete and the unreacted titanium particles were covered by a layer of TiAl 3 . In these samples, other intermetallic compounds such as TiAl 2 , TiAl and Ti 3 Al were observed to form upon heating beyond the combustion peak and are attributed to the solid-state reaction between unreacted titanium and TiAl 3 . Heating the samples with 25 at.% Al to 1273 K for an hour led to the formation of a homogenous Ti 3 Al product, while a multiphase product with a dominant TiAl phase was observed in samples containing 50 at.% Al. Calculations based on DSC data show that the formation of TiAl 3 through the reaction between solid titanium and molten aluminum is associated with an apparent activation energy of 195 ± 20 kJ mol -1 and an enthalpy of -114 ± 5 kJ mol -1 .

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Section: Tisupporting

confidence: 91%

Section: Introductionmentioning

confidence: 90%

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Sina

Iyengar

2015

J Therm Anal Calorim

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“…28) The chemical formula for the τ1 phase was (Ti 1-x Al x )(Al y Si 1-y ) 2 , where x ≤ 0.12 and 0.06 ≤ y ≤ 0.25. Consequently, the compositions of τ1 phase are expected to be 8-20 at% Al, 29.3 at% Ti, and 62.6-50 at% Si.…”

Section: Reactions Between the Ti Powders And The Al Meltmentioning

confidence: 99%

“…Consequently, the compositions of τ1 phase are expected to be 8-20 at% Al, 29.3 at% Ti, and 62.6-50 at% Si. Meanwhile, the chemical formula for the τ2 phase has also been de ned by Brukl, which was Ti (Al x Si 1-x ) 2 , with the x of 0.15-0.3.…”

Section: Reactions Between the Ti Powders And The Al Meltmentioning

confidence: 99%

“…1) During the last few decades, many studies have speci cally examined ceramic particle-reinforced Al alloy composites. 2) However, because a large difference exists between the coefcient of thermal expansion (CTE) of the Al matrix and ceramic reinforcements, large stresses can exist at their interfaces, thereby degrading the mechanical properties. However, the CTE of intermetallic compounds comparable to that of the Al matrix alloy.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Partial Remelting on Microstructure of Al-Si-Ti Bulk Alloy Prepared by Cold Pressing Mixed Powders

et al. 2016

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The microstructural evolution and phase transformations have been investigated during the partial remelting of a bulk alloy prepared by the cold pressing of A356, pure Ti and pure Al powders. A dropping experiment was used to investigate the reaction kinetics of Ti powders and the Al matrix simultaneously. The results show that a semi-solid microstructure with ne and spheroidal primary α-Al particles suspended in the liquid phase could be obtained after the bulk alloy was heated to 595 C for 30 min. The microstructural evolution process was divided into four stages, involving the transformation of the powders into primary particles, the formation of a liquid phase and the increase in its amount, which results in the formation of a continuous liquid layer, the rapid coarsening of the primary particles and the increase in the liquid phase amount, and the nal coarsening of the primary particles. Chemical reactions between the Ti powders and the Al element in the matrix occurred simultaneously. Next, core-shell structured, reinforced particles composing both an intermetallic shell and a soft Ti metal core formed in situ. The compact shell subsequently ruptured and peeled off when its thickness increased to a given value for a given size of Ti powder particles. Finally, the Ti powders were consumed completely because of the formation and the subsequent peeling of the shell. Results of the dropping simulation experiment show that the reaction product layer grows in a linear kinetic manner characterized by an activation energy of 374 kJ/mol.

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Industrial Use of High-Strength Intermetallic Compounds Based on Aluminides and Prospects for Extending Scope of Their Application

2023

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The effect of processing variables on the structure and chemistry of Ti-aluminide based LMCS

Cited by 40 publications

References 10 publications

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Effects of Partial Remelting on Microstructure of Al-Si-Ti Bulk Alloy Prepared by Cold Pressing Mixed Powders

Industrial Use of High-Strength Intermetallic Compounds Based on Aluminides and Prospects for Extending Scope of Their Application

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