Porosity and argon concentration in gas atomized γ-TiAl powder and hot isostatically pressed compacts

Intermetallic γ‐TiAl‐based alloys represent a new class of light‐weight structural materials for use at high temperatures. Because of their unique properties these alloys are considered for applications in aerospace and automotive industries. During the last decade both, alloy development and materials processing progressed significantly. New materials and powder metallurgy (PM) have formed a symbiosis since many decades. In fact, PM is an ancient technology which has been used for the processing for almost every metal or ceramic material. Therefore, it is hardly surprising that PM plays an important role in research and development of γ‐TiAl‐based alloys.

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“…[25,26] Argon is not soluble in metals and thus can not be extracted in the course of a PM-processing route. During compaction of powders, e.g.…”

Section: Argon In Atomized Powder Particlesmentioning

confidence: 99%

Powder Metallurgical Processing of Intermetallic Gamma Titanium Aluminides

Gerling¹,

Clemens

Schimansky³

2004

Adv Eng Mater

Self Cite

198

155

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“…In the case of forging, it is difficult to apply the hot forging process to TiAl alloys due to their inherent poor deformability and extremely high machining losses [3,4]. Besides, PM process has been limited by the freedom of size and shape and soundness [5]. Also, in TiAl alloys casting, the unacceptable surface reaction layer called 'alpha-case (a-case)' occurs due to the high reactivity of TiAl alloys in molten states [3].…”

Section: Introductionmentioning

confidence: 99%

Economic net-shape forming of TiAl alloys for automotive parts

Sung

Kim

2006

Intermetallics

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“…A reason for this behavior may be found in the very low solubility of O, N, and C in ␥-TiAl giving rise to the formation of oxides, nitrides, and carbides, which act as obstacles to the grain boundary motion. 38 The corresponding compacts are found to be free of pores. Impurity content of the starting powders (marked by #) and of the processed material after HIP.…”

Section: Discussionmentioning

confidence: 96%

Submicron-grained multiphase TiAlSi alloys: Processing, characterization, and microstructural design

et al. 2001

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Prealloyed powders of the intermetallic ␥-TiAl phase and the ceramic -Ti 5 Si 3 phase were high-energy milled and hot-isostatically pressed (HIP) to produce silicide dispersed composite materials with grain sizes in the submicron and nanometer range. The amorphous state of the as-milled powders crystallizes via a multistep decomposition reaction during degassing at 440°C and HIP. At a pressure of 200 MPa HIP-temperatures as low as 750°C are sufficient for a complete densification of the milled powder. The microstructure of the compacts is very homogeneous and consists of equiaxed ␥-TiAl crystals and -Ti 5 (Si,Al) 3 particles. Depending on the silicon content, these particles are interspersed within the grain boundary network of the ␥-TiAl phase or dispersed inside the ␥ grains. With respect to technical applications, submicron-grained composites are regarded as promising precursor materials that should allow for easy hot working in the as-prepared state as well as for high-temperature structural applications after a suitable transformation of the microstructure.

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Porosity and argon concentration in gas atomized γ-TiAl powder and hot isostatically pressed compacts

Cited by 42 publications

References 5 publications

Powder Metallurgical Processing of Intermetallic Gamma Titanium Aluminides

Powder Metallurgical Processing of Intermetallic Gamma Titanium Aluminides

Economic net-shape forming of TiAl alloys for automotive parts

Submicron-grained multiphase TiAlSi alloys: Processing, characterization, and microstructural design

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