Tensile Properties of Recrystallized and Unrecrystallized Tungsten at Elevated Temperatures

Abstract:

Tungsten has higher melting point than any other metals. Therefore, tungsten is applied to the electrode for resistance welding. The electrodes for resistance welding of tungsten are mainly used for fusing joining because they have high heat resistance and are hard to be alloyed with work metal pieces. However, the cracks on electrode surface occur during cyclic welding processes. In this study, to reveal the relationship between the elevated temperature deformation characteristics and fracture mechanism of recrystallized and unrecrystallized tungsten, tensile tests were carried out with varying strain rate and testing temperature. At 400°C, the total elongation at a strain rate of 1.4×10-1 s-1 in the recrystallized tungsten decreased more than the total elongation at the other strain rate. At 600°C, total elongation increased by approximately 10%, if the strain rate was increased from 1.4×10-3 s-1 to 1.4×10-1 s-1. Then, the recrystallized tungsten at the strain rate of 1.4×10-1 s-1 had more necking than that of 1.4×10-3 s-1. The may be caused by an environmental embrittlement due to oxygen in the high temperature atmosphere.

• Periodical: Materials Science Forum (Volumes 838-839)
• Pages: 272-277
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.838-839.272
• Online since: January 2016
• Authors: Nobuatsu Tano*, Junya Kobayashi, Goroh Itoh, Akira Kurumada, Shingo Mukae
• Keywords: Elevated Temperature, Strain Rate, Tensile Properties, Tungsten

References

[1] Syuhei　Iijima, Goroh Itoh, Shingo Mukae, Nobuhide Itoh, Relationship between degradation and microstructure in tungsten and molybdenum electrodes for fusing joining, The proceedings of the Japanese spring conference for the technology of plasticity, (2013).

[2] Syuhei Iijima, Goroh Itoh, Shingo Mukae, Takaaki Sakuma, Akira Kurumada, Tensile Properties of Tungsten at Elevated Temperature, The proceedings of the Japanese spring conference for the technology of plasticity, (2014) 285-286.

[3] J. H. Bechtold, P. G. Shewmon, Flow and fracture characteristics of annealed tungsten, Transactions of ASM. 46 (1954) 397-408.

[4] Seiji Yumoto, Toshiaki Maeda, Tyukou Konno, Kihon Kikai Kousaku (I), The Nikkan kogyo shinbunsya, Tokyo, (1980). (in Japanese).

[5] Omi Miyagawa, Kinzoku Zairyou Kougaku, Morikita publisher, Tokyo, (1976). (in Japanese).