Mechanical anisotropy and segregation in Mo5Si3 studied by EBSD
Artikel i vetenskaplig tidskrift, 2005
The cracking behaviour of indented areas in monolithic Mo5Si3 and segregation in Cr-alloyed Mo5Si3 have been studied by electron back-scattering diffraction (EBSD) in a scanning electron microscope (SEM). Vickers indentation of Mo5Si3 indicates preferred cleavage across the  direction, resulting in chipping if the indent is normal to the (001) plane. The other two alloyed Mo5Si3-based compounds studied in this work, i.e. Mo3Cr2Si3 and Mo3Ti2Si3, behave differently during heat treatment. Mo3Cr2Si3, on the one hand, shows unexpected additional X-ray reflections together with broadening of reflections after annealing, when compared to its as-cast condition. Observations of increased segregation upon annealing are made, presumably by a separation into Cr-lean and Cr-enriched (Mo,Cr)5Si3, especially in the <100> directions according to EBSD. Segregation of Cr is linked to additional reflections in X-ray diffraction (XRD). Mo3Ti2Si3, on the other, seems to be in chemical equilibrium in the as-cast state according to energy dispersive spectrometry (EDS) measurements, and there is little difference in XRD between as-cast and heat treated alloys.
Ternary alloy systems