The Contribution of High‐Energy X‐Rays and Neutrons to Characterization and Development of Intermetallic Titanium Aluminides

Schmoelzer, Thomas; Liss, Klaus-Dieter; Staron, Peter; Mayer, Svea; Clemens, Helmut

doi:10.1002/adem.201000296

Cited by 36 publications

(42 citation statements)

References 86 publications

(142 reference statements)

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“…Slits made of pure tungsten minimized undesired scattering and, thus, ensured a low background. Data evaluation was performed by means of the program Fit2D with respect to azimuthal integration [1,2] followed by a fitting procedure of the derived scattering curves with the program SANSFit based on a least-square method iteration as conducted in Ref. [3].…”

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confidence: 99%

In situ small-angle X-ray scattering study of the perovskite-type carbide precipitation behavior in a carbon-containing intermetallic TiAl alloy using synchrotron radiation

Schwaighofer¹,

Staron²,

Rashkova³

et al. 2014

Acta Materialia

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Intermetallic γ-TiAl based alloys of the latest generation, e.g. TNM alloys with a nominal composition of , exhibit the potential to be used in modern high-performance combustion engines due to their low density, high strength and creep-resistance as well as their good oxidation properties at elevated temperatures. Alloying with C can further improve the high-temperature performance both by solid solution hardening and/or carbide formation. In this study, starting from a supersaturated TNM-1C alloy the precipitation behavior and thermal stability of Perovskite-type carbides Ti 3 AlC during isothermal annealing at 750 °C and ensuing re-heating to 1200 °C is quantified by means of an in-situ small-angle X-ray scattering (SAXS) experiment using synchrotron radiation. Complementary, the formed hierarchical structures on the nano-scale, i.e. p-type carbide precipitates within ultra-fine γ-lamellae of the α 2 /γ-colonies, were investigated by means of monochromatic high-energy X-ray diffraction (HEXRD) in combination with transmission electron microscopy (TEM). Additionally, an explanation of an obtained diffraction phenomenon is given, i.e. streak formation which is caused by the very small lamellar spacing of the γ-phase within the α 2 /γ-colonies. It was also found that the geometrically well-defined nanostructure allows a correlation between the γ-laths thickness and a characteristic dimension of p-type carbides.The experiments were carried out at the HZG high-energy materials science beamline HEMS (P07). A sketch of the experimental setup is depicted in Fig. 1. The monochromatic beam with a mean energy of 100 keV is guided through the sample which is situated in a modified quenching and deformation dilatometer device DIL 805 A/D from Bähr Thermoanalyse, Germany. The diffraction patterns are recorded with a Perkin Elmer XRD 1622 flat panel detector in experimental hutch EH 3, whereas a mar345 Image Plate detector located behind in EH 4 is used to record the signal from small-angle scattering. The cylindrical sample with a size of 5 mm in diameter and 10 mm in length was heated inductively. The SAXS data were recorded with a sample-to-detector distance of 11.654 m and a frame rate of 20 images per hour. Slits made of pure tungsten minimized undesired scattering and, thus, ensured a low background. Data evaluation was performed by means of the program Fit2D with respect to azimuthal integration [1,2] followed by a fitting procedure of the derived scattering curves with the program SANSFit based on a least-square method iteration as conducted in Ref. [3]. More details about the experimental conditions and the obtained results are given in the original full-length paper in [4].

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mentioning

confidence: 99%

In situ small-angle X-ray scattering study of the perovskite-type carbide precipitation behavior in a carbon-containing intermetallic TiAl alloy using synchrotron radiation

Schwaighofer¹,

Staron²,

Rashkova³

et al. 2014

Acta Materialia

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“…The scheme to the left illustrates the pathway of high-energy X-rays (blue) from their generation at an insertion device in the storage ring, up to their diffraction from the specimen in the sample holder. An area detector at the front captures sets of Debye-Scherrer rings [52]. The photograph on the right shows the quenching and deformation dilatometer [64,66] as an example of a versatile sample environment installed at the PETRA III High Energy Materials Science (HEMS) beamline.…”

Section: Hexrd: State-of-the-art Instrumental Setupmentioning

confidence: 99%

“…In the insert at the top, a heated specimen is glowing during an in situ experiment. (Reproduced with permissions from Reference [52]. Copyright © Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, 2011).…”

Section: Hexrd: State-of-the-art Instrumental Setupmentioning

confidence: 99%

“…Individual reflection spots might also transform characteristically during an experiment emulating, for example, hot deformation. A simplified model of the development of reflection spots during hot working is proposed in [52]. The way in which the diffraction pattern is affected depends on the processes dominating in the material, e.g., whether a material or phase predominantly shows recovery or rather recrystallization under the conditions applied.…”

Section: General Considerations On the Mapping Of Deformation Recovementioning

confidence: 99%

“…Diffraction and scattering techniques using high-energy X-rays and neutrons have been shown to overcome most of the problems mentioned above [48,49,51,52]. Having been used as a tool for material characterization since the early beginnings of research activities on TiAl alloys [46,[53][54][55][56][57][58][59], they have successfully promoted the development of the alloy in various aspects ( Figure 2).…”

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confidence: 99%

See 2 more Smart Citations

In Situ Characterization Techniques Based on Synchrotron Radiation and Neutrons Applied for the Development of an Engineering Intermetallic Titanium Aluminide Alloy

Erdely

Schmoelzer

Schwaighofer

et al. 2016

Metals

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Abstract:Challenging issues concerning energy efficiency and environmental politics require novel approaches to materials design. A recent example with regard to structural materials is the emergence of lightweight intermetallic TiAl alloys. Their excellent high-temperature mechanical properties, low density and high stiffness constitute a profile perfectly suitable for their application as advanced aero-engine turbine blades or as turbocharger turbine wheels in next-generation automotive engines. As the properties of TiAl alloys during processing as well as during service are dependent on the phases occurring, detailed knowledge of their volume fractions and distribution within the microstructure is of paramount importance. Furthermore, the behavior of the individual phases during hot deformation and subsequent heat treatments is of interest to define reliable and cost-effective industrial production processes. In situ high-energy X-ray diffraction methods allow tracing the evolution of phase fractions over a large temperature range. Neutron diffraction unveils information on order-disorder transformations in TiAl alloys. Small-angle scattering experiments offer insights into the materials' precipitation behavior. This review attempts to shine a light on selected in situ diffraction and scattering techniques and the ways in which they promoted the development of an advanced engineering TiAl alloy.

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Advanced Intermetallic Titanium Aluminides

Clemens

Smarsly

Güther³

et al. 2016

Proceedings of the 13th World Conference on Titanium

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After almost four decades of intensive fundamental research and development activities intermetallic titanium aluminides have found application in aircraft and automotive engines. The advantage of this class of innovative high-temperature materials is their low density in combination with good strength and creep properties up to 800°C. A drawback, however, is their limited ductility at room temperature, which is reflected in a low plastic fracture strain. Advanced engineering TiAl alloys are complex multi-phase materials which can be processed by ingot or powder metallurgy, precision casting methods as well as additive manufacturing, e.g. electron beam melting. Each production process leads to specific microstructures which can be altered and optimized by thermo-mechanical processing and/or subsequent heat-treatments. The aim of these heat-treatments is to provide a microstructure with balanced mechanical properties, i.e. sufficient ductility at room temperature as well as creep strength at elevated temperature. In order to achieve this goal, the knowledge of the occurring solid state phase transformations including order/disorder reactions is essential. Therefore, thermodynamic calculations were conducted at first to predict the phase diagram of engineering TiAl alloys. After experimental verification, these phase diagrams provided the basis for the development of the heat-treatments mentioned above. To account the influence of deformation and kinetic aspects sophisticated ex-and in-situ methods have been employed to investigate the evolution of the microstructure during thermo-mechanical processing and subsequent heat-treatments. For example, in-situ high-energy Xray diffraction was conducted to study dynamic recovery and recrystallization processes during hot-deformation tests. Summarizing all results a consistent picture regarding processing and mechanical properties of advanced engineering TiAl alloys can be given.

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The Contribution of High‐Energy X‐Rays and Neutrons to Characterization and Development of Intermetallic Titanium Aluminides

Cited by 36 publications

References 86 publications

In situ small-angle X-ray scattering study of the perovskite-type carbide precipitation behavior in a carbon-containing intermetallic TiAl alloy using synchrotron radiation

In situ small-angle X-ray scattering study of the perovskite-type carbide precipitation behavior in a carbon-containing intermetallic TiAl alloy using synchrotron radiation

In Situ Characterization Techniques Based on Synchrotron Radiation and Neutrons Applied for the Development of an Engineering Intermetallic Titanium Aluminide Alloy

Advanced Intermetallic Titanium Aluminides

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