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<p>This study systematically reveals the effects of temperature and strain rate on the nanoindentation mechanical behavior and deformation mechanisms of <i>γ</i>/<i>α</i><sub>2</sub> fully lamellar TiAl polycrystals (FL-<i>γ</i>/<i>α</i><sub>2</sub>-TiAl-PC) and <i>γ</i>-TiAl polycrystals (<i>γ</i>-TiAl-PC) by molecular dynamics (MD) simulations. The experimental nanoindentation results are primarily used to examine the influence of loading rate variations on the overall force–displacement response trend. Simulation results indicate that temperature exerts a more significant regulatory effect on the mechanical behavior of materials than loading rate. Compared to <i>γ</i>-TiAl-PC, FL-<i>γ</i>/<i>α</i><sub>2</sub>-TiAl-PC exhibits higher load-bearing capacity, primarily attributed to the constraint and strengthening effect of the phase boundary (PB) on dislocation slip. The indentation force of both materials is insensitive to changes in loading rate but exhibits an overall decreasing trend with increasing temperature, and the strengthening effect of PB is significantly weakened at high temperatures. Further analysis found that the PB and grain boundary (GB) regions are the primary enrichment zones for centrosymmetry parameter (CSP) and high shear strain. As the temperature rises, the V-Mises stress gradually propagates along the PB/GB region, forming a continuous high-stress zone that spans the interface under high-temperature conditions. This indicates increased deformation at the interface and may be accompanied by slip behavior at the interface. This study contributes to a deepened understanding of interface-related deformation mechanisms in TiAl alloys.</p> Graphical Abstract <p></p>

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Study on influence of temperature and strain rate on nanoindentation behavior of γ/α2 fully lamellar TiAl polycrystals

  • 期刊论文

  • 发表日期：

    2026年7月22日

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  • Min Zheng,
  • Xiaobin Dai,
  • Dingfeng Qu,
  • Bo Song,
  • Weihua Chen,
  • Xingchun Wei,
  • Zengfeng Gao,
  • Zongxiao Zhu

摘要

This study systematically reveals the effects of temperature and strain rate on the nanoindentation mechanical behavior and deformation mechanisms of γ/α2 fully lamellar TiAl polycrystals (FL-γ/α2-TiAl-PC) and γ-TiAl polycrystals (γ-TiAl-PC) by molecular dynamics (MD) simulations. The experimental nanoindentation results are primarily used to examine the influence of loading rate variations on the overall force–displacement response trend. Simulation results indicate that temperature exerts a more significant regulatory effect on the mechanical behavior of materials than loading rate. Compared to γ-TiAl-PC, FL-γ/α2-TiAl-PC exhibits higher load-bearing capacity, primarily attributed to the constraint and strengthening effect of the phase boundary (PB) on dislocation slip. The indentation force of both materials is insensitive to changes in loading rate but exhibits an overall decreasing trend with increasing temperature, and the strengthening effect of PB is significantly weakened at high temperatures. Further analysis found that the PB and grain boundary (GB) regions are the primary enrichment zones for centrosymmetry parameter (CSP) and high shear strain. As the temperature rises, the V-Mises stress gradually propagates along the PB/GB region, forming a continuous high-stress zone that spans the interface under high-temperature conditions. This indicates increased deformation at the interface and may be accompanied by slip behavior at the interface. This study contributes to a deepened understanding of interface-related deformation mechanisms in TiAl alloys.

Graphical Abstract