Lattice Stability and Elastic Properties of Zr-Ti-X Alloys (X = Al, V) by the First Principles Study

oleh: Wenxiong Duan, Xiaoping Liang, Xiangguan Yang, Yu Wang, Baifeng Luan

Format: Article
Diterbitkan: MDPI AG 2020-10-01

Deskripsi

Based on a certain ratio of Zr and Ti atomic fractions according to Zr<sub>47</sub>Ti<sub>45</sub>Al<sub>5</sub>V<sub>3</sub> (wt.%), the lattice constants, lattice stability, and elastic properties of Zr-Ti-X alloys (X = Al, V) in body-centered cubic (BCC) (β phase) and hexagonal close-packed (HCP) (α phase) crystal structures were studied using first-principles calculations. It is shown that Al acts as an α stabilizer for Zr-Ti-Al alloys and V can stabilize the β phase for Zr-Ti-V alloys. As the mass fraction of Al increases from 4 wt.% (Zr<sub>55</sub>Ti<sub>41</sub>Al<sub>4</sub>) to 6.8 wt.% (Zr<sub>53.2</sub>Ti<sub>40</sub>Al<sub>6.8</sub>), these alloys all have relatively good strength, hardness, and rigidity, however, their ductility deteriorated with the increasing of Al mass fraction. When the mass fraction of V in Zr-Ti-V alloys is 2.4 wt.%, Zr<sub>55.6</sub>Ti<sub>42</sub>V<sub>2.4</sub> (wt.%) achieved the best strength, hardness, and rigidity, when the mass fraction of V increases from 0 (Zr<sub>57</sub>Ti<sub>43</sub>) to 12 wt.% (Zr<sub>50.2</sub>Ti<sub>37.8</sub>V<sub>12</sub>), their ductility improved. The changes of phase compositions and structure with Al content or V content distinctly affect mechanical properties of ternary Zr-Ti-X alloys (X = Al, V), the amount of Zr and Ti could be factors that impact the mechanical properties of the multiphase Zr<sub>47</sub>Ti<sub>45</sub>Al<sub>5</sub>V<sub>3</sub> from the point of view of ternary Zr-Ti-Al and Zr-Ti-V compositions.