|Microstructure examination of functionally graded NiTi/NiAl/Ni3Al intermetallic compound produced by self-propagating high-temperature synthesis|
KILIC, M., KIRIK, I., OKUMUS, M.
vol. 55 (2017), no. 2, pp. 97 - 106
In this study, functionally graded Ni3Al/NiAl/NiTi material was produced by Ni-Ti-Al powders at 150 MPa compaction pressure and at different pre-heating temperatures (200, 300, and 400 °C) using self-propagating high-temperature synthesis (SHS) method. This material was ignited with the help of external heat, after it was subjected to pre-heating under argon atmosphere, following the stages of atomic weighing, mixing, and pressing of powders under a defined compaction pressure respectively before the ignition. Microstructure examinations of the functionally graded material (FGM) being successfully synthesized after ignition, were performed by using an optical microscope, SEM (scanning electron microscope), and EDS (energy dispersive spectroscopy) methods. It was observed that owing to the exothermic reaction occurring as a result of self-propagating high-temperature synthesis, the cohesion of powders consisting of compacted 3 different layers occurred, combustion pits formed in samples after ignition, and intermediate phases with primary phases and dendritic branches were formed at the microstructure analysis.
functionally graded material (FGM), self-propagating high-temperature synthesis (SHS), microstructure
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