Deformation behavior of HfNbTaTiZr high entropy alloy singe crystals and polycrystals

The Grain Boundary Wetting Phenomena in the Ti-Containing High-Entropy Alloys: A Review

“…If the two-phase S + L area of the phase diagram does not contain any tie lines, T wmax or T wmin , of the GB wetting transition, then the one-phase solid solution polycrystal with typical dendritic structure forms after solidification of the melt. This is the case of the equiatomic HfNbTaTiZr high-entropy alloy with bcc structure prepared by plasma arc melting (Figure 2a) [5]. After homogenization at 1473 K, this dendritic structure disappears and the bcc solid solution becomes homogenous (Figure 2b).…”

“…A typical sample of such a microstructure is shown in Figure 2 from Ref. [5]. When the melt is cooled, the second dashed line (Route 2) on the right-hand side of Figure 1 intersects not only the lines of the bulk liquidus and eutectic transformation but also the GB line at T wmin .…”

“…In the majority of cases, multicomponent alloys are synthesized by crystallization from the melt (arc or induction melting in vacuum or argon [5][6][7][13][14][15][16][17][18][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43], plasma spark sintering [19], electric current assisted sintering [20,21], laser or plasma cladding deposition of coatings [44][45][46][47][48][49][50][51][52][53][54][55], additive manufacturing by the laser-powder bed fusion [56,57] or laser-metal deposition [58], self-propagating high-temperature synthesis (SHS) [59], and by brazing within the brazing joints [60,61]). Figure 1 shows a schematic phase diagram for the simplest case when there are on...…”

“…They remain in the solidified sample in the form of a continuous network surrounding the grains poor in the second component (see, for example, the microstructure in Figure 4). discuss the crystallization from the melt during arc or induction melting in vacuum or argon [5][6][7][13][14][15][16][17][18][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. If the two-phase S + L area of the phase diagram does not contain any tie lines, Twmax or Twmin, of the GB wetting transition, then the one-phase solid solution polycrystal with typical dendritic structure forms after solidification of the melt.…”

“…High-entropy alloys containing titanium can be conventionally divided into two groups. The first group includes alloys containing zirconium and hafnium, together with titanium [5][6][7]. Ti, Zr and Hf are in the same group in the Mendeleev periodic table of elements.…”