Inhibition of grain coarsening up to 1000 °C in (AlCrNbSiTiV)N superhard coatings

High-entropy nitride films were deposited by reactive sputtering from an AlCrNbSiTiV equimolar alloy target. The films persisted in single solution phase with an NaCl structure and retained their nanograin size, even after annealing at 1000 °C for 5 h. The films were superhard (>40 GPa), and have a high entropy effect that stabilizes the solution phase, and a severe-lattice-distortion effect that inhibits nanograin coarsening. The proposed inhibition mechanism for such high-entropy nitride coatings is based on thermodynamics.

[1]  M. Odén,et al.  Mechanical properties and machining performance of Ti1−xAlxN-coated cutting tools , 2005 .

[2]  G. J. Fan,et al.  A model for the inverse Hall–Petch relation of nanocrystalline materials , 2005 .

[3]  James C. M. Li,et al.  Possibility of Subgrain Rotation during Recrystallization , 1962 .

[4]  K. Lu,et al.  Homogeneous Nucleation Catastrophe as a Kinetic Stability Limit for Superheated Crystal , 1998 .

[5]  Shou-Yi Chang,et al.  Preparation and characterization of AlCrTaTiZr multi-element nitride coatings , 2006 .

[6]  K. Easterling,et al.  Phase Transformations in Metals and Alloys , 2021 .

[7]  J. Yeh,et al.  Effects of substrate temperature and post-annealing on microstructure and properties of (AlCrNbSiTiV)N coatings , 2009 .

[8]  F. J. Humphreys,et al.  Recrystallization and Related Annealing Phenomena , 1995 .

[9]  John Arents,et al.  Thermodynamics of solids , 1962 .

[10]  Lars Hultman,et al.  Microstructural design of hard coatings , 2006 .

[11]  B. Fultz,et al.  Average widths of grain boundaries in nanophase alloys synthesized by mechanical attrition , 1995 .

[12]  J. Yeh,et al.  Effects of substrate bias on structure and mechanical properties of (AlCrNbSiTiV)N coatings , 2009 .

[13]  C. Mitterer,et al.  Self-organized nanostructures in the Ti–Al–N system , 2003 .

[14]  J. Yeh.  Recent progress in high-entropy alloys , 2006 .

[15]  Chun-Huei Tsau,et al.  Influence of substrate bias, deposition temperature and post-deposition annealing on the structure and properties of multi-principal-component (AlCrMoSiTi)N coatings , 2008 .

[16]  J. Procházka,et al.  Conditions required for achieving superhardness of ≥45 GPa in nc-TiN/a-Si3N4 nanocomposites , 2004 .