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Niobium Wires as Space Holder and Sintering Aid for Porous NiTi

Authors


  • This research was supported by the United States National Science Foundation (Grant DMR-0505772). A. B. also gratefully acknowledges support from the Faculty of Engineering at Kasetsart University (Thailand) and technical advice from Dr. Alan Brothers.

Abstract

When NiTi powder compacts containing Nb wires are heated above 1 170 °C, each Nb wire reacts with adjacent NiTi powders to form a eutectic liquid which wicks into the space between the remaining NiTi powders. This creates a macropore at the location of the Nb wire while eliminating the microporosity between NiTi powders which is filled with a NiTi/Nb eutectic phase after solidification. This novel method produces – in a single step and without applied pressure – a dense NiTi matrix with elongated pores suitable for shape memory or superelastic applications such as bone implants, dampeners and actuators.

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