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Niobium Wires as Space Holder and Sintering Aid for Porous NiTi


  • 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.


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.