The grain refinement of zinc-aluminum alloys by titanium

The effect of ultrasonic treatment on the mechanisms of grain formation in as-cast high purity zinc

“…For instance, the addition of TiB 2 to certain Al alloys [9], Zr to Al-free Mg alloys [10] and Al -Ti or Zn -Ti master alloys to hypereutectic Zn -Al alloys [11,12] results in the refinement of as-cast grain size. In the case of pure metals, planar solidification starts at the mold wall and when the melt is thermally undercooled, new spherical crystals may nucleate on potent nucleants in the liquid and grow as equiaxed grains [13].…”

EBSD Study of ZnAl25 Alloy Inoculated with ZnTi4 Master Alloy

“…For example, permanent-mould-cast ZA27 alloy increases its elongation on α' refinement from 7% to 18% [1], while sand-cast binary Zn-25wt%Al alloy (ZnAl25) increases its elongation from 12% to 20% [2]. In industry, Al-Ti and Al-Ti-B master alloys (MA) are used to refine the α' dendrites [1,[3][4][5][6]. This refinement is attributed to heterogeneous nucleation.…”

“…This refinement is attributed to heterogeneous nucleation. The centres of nucleation postulated in [5] are particles of composition Ti 2 Al 5 Zn observed within refined α' grains in chill-and sand-cast Zn-24wt%Al alloy inoculated with Al-5wt%Ti (AlTi5) MA. On the other hand, particles of a different phase -Ti(Al,Zn) 3 -were found within the refined α' grains of an ZnAl25 alloy inoculated with AlTi4 or AlTi5B1 master alloys and slowly cooled in a graphite crucible [7].…”

“…On the other hand, particles of a different phase -Ti(Al,Zn) 3 -were found within the refined α' grains of an ZnAl25 alloy inoculated with AlTi4 or AlTi5B1 master alloys and slowly cooled in a graphite crucible [7]. The Al-Ti and Al-Ti-B master alloys require a melt temperature of 700 -750 o C for their quick and total dissolution [5][6]. This range of temperature is 150-200 K higher than the 550-600 o C range recommended for these alloys [8].…”

Determination of Al Site Preference in L1₂ TiZn₃ - Base Trialuminides

“…The authors of [4] synthetised Al 3 Ti-Zn trialuminides by sintering pure Al, Ti and Zn powders and they obtained a mixture of the D0 22 and L1 2 phases, which makes it difficult to analyse sites location. In foundry practice of melting the high-aluminium zinc alloys there are used Al-Ti [8], [10], [13] and, newly introduced, Zn-Ti master alloys (MA) [5 -8] which introduce particles serving as centres of heterogeneous nucleation of the α' dendrites of ZnAl solid solution [5 -7], [14]. During the investigations aimed at identification of the heterogeneous substrates of the α' dendrites nucleation, there was stated that Al 3 Ti phase, introduced with a Al-Ti MA, transforms within the Zn-Al melt into ternary Ti-Al-Zn phase.…”