Snoek-type damping performance in strong and ductile high-entropy alloys

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Science Advances  17 Jun 2020:
Vol. 6, no. 25, eaba7802
DOI: 10.1126/sciadv.aba7802
  • Fig. 1 Damping properties of the oxygen- or nitrogen-doped Ta0.5Nb0.5HfZrTi HEAs.

    Temperature-dependent variation of damping capacity (indexed by tanδ) of the as-cast (A) Ta0.5Nb0.5HfZrTi, (B) (Ta0.5Nb0.5HfZrTi)98O2, and (C) (Ta0.5Nb0.5HfZrTi)98N2 HEAs. The measurements were conducted on a multifunction internal friction apparatus by the forced vibration at 0.5, 1.0, 2.0, and 4.0 Hz, respectively. The maximum strain amplitude is 2 ×10−4, and the heating rate is 2 K min−1 in the measured temperature range. The three HEAs present a promising high damping property with the peak capacity of damping tanδmax > 0.01. The white arrows in (B) and (C) indicate the additional low-temperature peak in the (Ta0.5Nb0.5HfZrTi)98O2 and (Ta0.5Nb0.5HfZrTi)98N2 HEAs, respectively. (D) Arrhenius plots of the Snoek damping peak of the current HEAs, and the slope of the linear variation of ln(2πf) versus 1/ Tp yields the activation energy H of the corresponding stress-induced reorientation process.

  • Fig. 2 A comparison of the damping properties of the model HEAs with the traditional Snoek-type damping alloys.

    (A) The damping peak temperature Tp and the corresponding activation energy H in the current HEAs and other conventional Snoek-type damping alloys (see squares). The Tp and H of the current HEAs are much higher than that of the traditional alloys. (B) Plot of the peak capacity of damping tanδmax, the width of the Snoek damping peak ∆T, and the peak temperature Tp. The data for the typical Snoek-type damping alloys are plotted for comparison. The current Snoek-type high-damping HEAs exhibit higher Tp and ∆T, which means that the designed HEAs can be used at a much higher temperature and a wider operating temperature range.

  • Fig. 3 Mechanical properties of the oxygen- or nitrogen-doped Ta0.5Nb0.5HfZrTi HEAs.

    Room temperature tensile stress-strain curves for the as-cast Ta0.5Nb0.5HfZrTi and its corresponding 2.0 at % oxygen- or nitrogen-dissolved HEAs. Adding interstitials leads to the simultaneous strengthening and ductilizing.

  • Fig. 4 Microstructure revolution of the oxygen- or nitrogen-doped Ta0.5Nb0.5HfZrTi HEAs.

    (A) XRD patterns of the as-cast HEAs and (B to D) the corresponding EBSD images. All the as-cast HEAs have single bcc lattice structure. (E to G) STEM-HAADF images for the [011]bcc crystal axis with differently adjusted contrast to reveal the existence of compositional clusters in the (Ta0.5Nb0.5HfZrTi)98O2 HEA and the corresponding STEM-ABF image to reveal the ordered oxygen complexes. The white arrows indicate the positions of the oxygen atom columns. (H) Atom probe tomography reconstruction from the analysis of a specimen from the (Ta0.5Nb0.5HfZrTi)98O2 HEA. The threshold for the isocomposition surface is 3.5 at % O, revealing the presence of ordered oxygen complexes. (I) Proxigram from the interface matrix/ordered oxygen complex showing the enrichment of O, Ti, Zr and slightly depletion of Ta, Nb, Hf. a.u., arbitrary units.

  • Fig. 5 Mechanism analysis of the strong and ductile high-damping HEAs.

    Temperature dependence of internal friction (at 1.0 Hz) and the fitting results in the (A) Ta0.5Nb0.5HfZrTi, (B) (Ta0.5Nb0.5HfZrTi)98O2, and (C) (Ta0.5Nb0.5HfZrTi)98N2 HEAs. The filled black circles are the experimental points, and the cyan curves are the sum of the cumulative fitting peaks. The green and magenta curves correspond to the relaxation process, which are due to the stress-induced ordering of the randomly distributed interstitial atoms (RDIAs). The red curve in (B) and the blue curve in (C) indicate the reorientation of ordered oxygen complexes (OOCs) and ordered nitrogen complexes (ONCs), respectively. The fitting correlation index is more than 0.99. (D) Schematic diagram of designing Snoek-type high-damping HEAs with high damping capacities and superb mechanical properties. OICs, ordered interstitial complexes. Interstitial strengthening contributes to the high strength, a sufficient concentration of randomly distributed interstitial atoms favors the enhancement of damping capacity, and an abundant OIC serves to improve the ductility.

Supplementary Materials

  • Supplementary Materials

    Snoek-type damping performance in strong and ductile high-entropy alloys

    Zhifeng Lei, Yuan Wu, Junyang He, Xiongjun Liu, Hui Wang, Suihe Jiang, Lin Gu, Qinghua Zhang, Baptiste Gault, Dierk Raabe, Zhaoping Lu

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    • Peak analysis
    • Table S1
    • Figs. S1 and S2

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