Papers by Keyword: Zn-Ti Master Alloy

Abstract: In this paper, Zn-6Ti master alloy was produced and characterized by XRD and SEM. It was found that α-Al dendritic grains in Zn-25Al alloy were remarkably refined after the addition of Zn-6Ti master alloy, with the size remarkably reduced and the morphology changed from complex dendrite to rose-like or granular (equiaxed particle) structure. Lower solidification temperature of the Zn-Al melt was found to further promote the formation of granular (equiaxed particle) α-Al grain in Zn-25Al alloy with the addition of Zn-6Ti master alloy. The mechanism for the grain refinement is discussed based on the SEM observation of TiAl _3-x Zn_x particles at the center of α-Al grain in Zn-25Al alloy.

Abstract: The atoms site preference in the Al₃Ti-Zn system has been studied using H. Rietveld method. The L12 Ti(Al, Zn)₃ particles evolve in a ZnAl25 melt from the L1₂TiZn₃ particles in the ZnTi4 master alloy. It is found that Zn is replaced by Al during the transformation TiZn₃ → Ti(Al, Zn)₃. In the evolving fcc L12 Ti(Al, Zn)₃ phase Ti occupies (0, 0, 0) position while Al and Zn occupy (0, 0.5, 0.5) position, similarly to Al and X in the Al₃Ti-X systems, where X = Ni, Cr, Mn, Cu, Ag, Pd [1, 2].

Abstract: The microstructure of cast Zn-25wt%Al alloy inoculated by addition of a Zn-4wt%Ti master alloy (ZnTi4) has been studied using scanning electron microscopy and electron back-scatter diffraction (EBSD). It is found that Ti(Al,Zn)₃ particles act as nucleation centres for grains of the primary solid solution of Zn in Al (α' phase). The Ti(Al,Zn)₃ particles evolve in melt from the TiZn₃ particles in the ZnTi4 master alloy. EBSD shows that α' phase dendrites are in the same crystallographic orientation as the Ti(Al,Zn)₃ particles on which they nucleate. It is also found that some of the Ti(Al,Zn)₃ particles do not have any well-defined crystallographic orientation relationship with the α' phase. These particles were probably pushed and then engulfed by growing α' grains which had already nucleated on other particles.