Microstructures and mechanical properties of TiAl alloys consolidated by spark plasma sintering

Couret, Alain; Molenat, G.; Galy, Jean; Thomas, Marc

doi:10.1016/j.intermet.2008.06.015

Cited by 147 publications

(84 citation statements)

References 15 publications

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“…This is consistent with what has been observed by Couret et al [12] for homogeneous microstructures along the sample radius with a sintering temperature in the α + λ region. Figure 4(a) shows the temperatures measured in the graphite die at h = 0 and r = 22, 16, 11, and 6 mm, respectively, during an experiment where temperature has been increased in five stages.…”

Section: Tialsupporting

confidence: 93%

Temperature Control in Spark Plasma Sintering: An FEM Approach

Molenat

Durand

Galy

et al. 2010

Journal of Metallurgy

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Powder consolidation assisted by pulsed current and uniaxial pressure, namely, Spark Plasma Sintering (SPS), is increasingly popular. One limitation however lies in the difficulty of controlling the sample temperature during compaction. The aim of this work is to present a computational method for the assembly temperature based on the finite elements method (FEM). Computed temperatures have been compared with experimental data for three different dies filled with three materials with different electrical conductivities (TiAl, SiC, Al 2 O 3 ). The results obtained are encouraging: the difference between computed and experimental values is less than 5%. This allows thinking about this FEM approach as a predictive tool for selecting the right control temperatures in the SPS machine.

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Section: Tialsupporting

confidence: 93%

Temperature Control in Spark Plasma Sintering: An FEM Approach

Molenat

Durand

Galy

et al. 2010

Journal of Metallurgy

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“…During the SPS, the temperature can induce phase transformation and thus affect the microstructure and densification. For a given experiment, the actual temperature could even be 160 • C higher than the monitored SPS temperature [19]. When the sintering temperature was 1150 • C, it was deduced that the actual temperature of the powders could be higher than 1260 • C (T e ).…”

Section: Microstructure Evolutionmentioning

confidence: 97%

“…For the sample sintered at 1150 • C, the high strength and considerable plasticity was attributed to the high density and small grain size. However, the poor strength and limited plasticity of the lamellar microstructure (1250 • C) was caused by the lack of texture [19]. Therefore, the dislocations could propagate more easily and thus initiate the crack, which eventually led to the rapid failure of the sample.…”

Section: Mechanical Propertymentioning

confidence: 99%

The Microstructure Evolution, Mechanical Properties and Densification Mechanism of TiAl-Based Alloys Prepared by Spark Plasma Sintering

Wang

Yuan

Qiang

2017

Metals

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Abstract:The microstructure evolution and mechanical properties of a Ti-Al-Cr-Nb alloy prepared by spark plasma sintering (SPS) at different temperatures and stresses were investigated in detail. Sintering temperature plays a key role in the densification process and phase transformation, which determines the microstructure. The mechanical properties of the sintered alloys depend on the microstructure caused by the sintering. Furthermore, the densification process and mechanism of TiAl-based metallic powders during SPS were studied based on experimental results and theoretical analysis, the results of which will help fabricate these kinds of intermetallic alloys using a powder metallurgy technique and accelerate their industrial applications.

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“…[30,31] Seo et al [32] obtained an average colony size lower than 100 lm for investment casting. For spark-plasma sintering Ti-47Al-2Cr-2Nb, the average colony size was approximately 150 lm, [33] whereas the average colony size for an investment cast Ti-45Al-2Nb-2Mn+0.8 vol pct TiB 2 intermetallic ranged between 20 and 100 lm. [15] In the current material, the size distribution of the colonies was large (52 to 634 lm), a feature that may be associated with the abnormal geometry of the centrifugal cast blade.…”

Section: A Microstructurementioning

confidence: 98%

In Situ Observations of the Deformation Behavior and Fracture Mechanisms of Ti-45Al-2Nb-2Mn + 0.8 vol pct TiB2

Muñoz‐Moreno

Boehlert

Pérez‐Prado

et al. 2011

Metall Mater Trans A

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The deformation and fracture mechanisms of a nearly lamellar Ti-45Al-2Nb-2Mn (at. pct) + 0.8 vol pct TiB 2 intermetallic, processed into an actual low-pressure turbine blade, were examined by means of in situ tensile and tensile-creep experiments performed inside a scanning electron microscope (SEM). Low elongation-to-failure and brittle fracture were observed at room temperature, while the larger elongations-to-failure at high temperature facilitated the observation of the onset and propagation of damage. It was found that the dominant damage mechanisms at high temperature depended on the applied stress level. Interlamellar cracking was observed only above 390 MPa, which suggests that there is a threshold below which this mechanism is inhibited. Failure during creep tests at 250 MPa was controlled by intercolony cracking. The in situ observations demonstrated that the colony boundaries are damage nucleation and propagation sites during tensile creep, and they seem to be the weakest link in the microstructure for the tertiary creep stage. Therefore, it is proposed that interlamellar areas are critical zones for fracture at higher stresses, whereas lower stress, high-temperature creep conditions lead to intercolony cracking and fracture.

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Microstructures and mechanical properties of TiAl alloys consolidated by spark plasma sintering

Cited by 147 publications

References 15 publications

Temperature Control in Spark Plasma Sintering: An FEM Approach

Temperature Control in Spark Plasma Sintering: An FEM Approach

The Microstructure Evolution, Mechanical Properties and Densification Mechanism of TiAl-Based Alloys Prepared by Spark Plasma Sintering

In Situ Observations of the Deformation Behavior and Fracture Mechanisms of Ti-45Al-2Nb-2Mn + 0.8 vol pct TiB2

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