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A Hoffmann - One of the best experts on this subject based on the ideXlab platform.

  • fracture strength and microstructure of ods tungsten alloys
    International Journal of Refractory Metals & Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    Abstract In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible.

  • Fracture strength and microstructure of ODS tungsten alloys
    International Journal of Refractory Metals and Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible. © 2010 Elsevier Ltd. All rights reserved.

I. Wesemann - One of the best experts on this subject based on the ideXlab platform.

  • fracture strength and microstructure of ods tungsten alloys
    International Journal of Refractory Metals & Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    Abstract In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible.

  • Fracture strength and microstructure of ODS tungsten alloys
    International Journal of Refractory Metals and Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible. © 2010 Elsevier Ltd. All rights reserved.

P. Heel - One of the best experts on this subject based on the ideXlab platform.

  • fracture strength and microstructure of ods tungsten alloys
    International Journal of Refractory Metals & Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    Abstract In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible.

  • Fracture strength and microstructure of ODS tungsten alloys
    International Journal of Refractory Metals and Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible. © 2010 Elsevier Ltd. All rights reserved.

W. Spielmann - One of the best experts on this subject based on the ideXlab platform.

  • fracture strength and microstructure of ods tungsten alloys
    International Journal of Refractory Metals & Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    Abstract In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible.

  • Fracture strength and microstructure of ODS tungsten alloys
    International Journal of Refractory Metals and Hard Materials, 2010
    Co-Authors: I. Wesemann, P. Heel, W. Spielmann, A Hoffmann
    Abstract:

    In many high Temperature applications tungsten is superior to molybdenum alloys. For structural components very often joining technology is the limiting factor. If brazing or welding is used ductility at room Temperature has to be considered. Particularly when handling or transporting they run the risk of brittle fracture. Relevant properties are sufficient fracture strength and ductility at ambient Temperatures after high Temperature annealing as well as high Recrystallization Temperature. We studied several tungsten alloys performing 3 point bending tests, annealing experiments and metallographic examinations. In respect to environmental considerations possible alloys should not contain thoria. Alloying with rare earth oxides enhance the fracture strength at ambient Temperatures after high Temperature annealing and increases the Recrystallization start Temperature. The results indicate that suitable thermomechanical treatment increases the Recrystallization Temperature by more than 500 °C and improve the fracture strength by a factor of 1.5. Favourable results with Th-free tungsten alloys are possible. © 2010 Elsevier Ltd. All rights reserved.

David Porter - One of the best experts on this subject based on the ideXlab platform.

  • effect of austenite grain structure on the strength and toughness of direct quenched martensite
    Journal of Alloys and Compounds, 2013
    Co-Authors: Antti Kaijalainen, Pasi Suikkanen, Teijo Limnell, L P Karjalainen, Jukka Komi, David Porter
    Abstract:

    Abstract The effect of prior austenite grain structure on the microstructure and properties of two low alloyed hot-rolled and direct-quenched martensitic steels was investigated. Strength properties were determined using uniaxial tensile testing, while toughness properties were characterized by using Charpy-V and fracture toughness tests. Microstructures were characterized using OM, SEM, EBSD and a novel EBSD-based image quality (IQ) technique. It was found that an increase in the rolling reduction in the non-Recrystallization Temperature regime of austenite was an effective way to improve the strength, impact and fracture toughness without a significant decrease in uniform elongation. In addition, this approach also decreased the in-plane anisotropy of the tensile and toughness properties. Refinement of the equiaxed austenite grain structure during rolling in the Recrystallization Temperature regime (roughing) also improved the strength and toughness properties, but the effect was found to be weaker than the effect of rolling in the non-Recrystallization regime. In toughness testing, a correlation was found between the Charpy-V 28J transition Temperature and the fracture toughness characteristic Temperature T 0 . However, the correlation differs significantly from that reported in the literature for lower strength ferritic steels. In all cases, the steel microstructures consisted of mainly auto-tempered martensite and lower bainite. A brief discussion of the microstructural features controlling the strength and toughness properties is given.