Net-shape processing of NiTi alloys by micro metal injection moulding (micro-MIM)

Nickel-Titanium alloys have been of high research interest in recent years due to their shape memory and superelastic properties, making them especially suitable as actor devices. Micro Metal Injection Moulding (micro-MIM) can open up new fields for applications for small NiTi parts of complex geometry, for example in biomedical or transport applications. For setting up the micro-MIM process for this material, investigations were conducted using very fine prealloyed NiTi powders. Micro tensile test specimens were moulded and subsequently sintered under Argon atmosphere using different heating rates and dwell temperatures. Density up to 97 % was obtained after sintering. Oxygen and carbon contents were found to decrease with increasing heating rate. High amounts of NiTi phase were found by means of EDX analysis. Additionally some Ti2Ni and Ti-rich secondary phases were detected. DSC measurements were carried out after different heat treatments to determine phase transformation temperatures. Entnommen aus <a_href="http://www.fiz-technik.de/db/b_tema.htm" target="_blank">TEMA</a>