Trends in formation energies and elastic moduli of ternary and quaternary transition metal nitrides

Alloying effects on the structure and elastic properties of hard coatings based on ternary transition metal (M = Ti, Zr or Ta) nitrides

“…In particular, cubic Ta-rich Ti 1 − x Ta x N alloys (x ≥ 0.75) are expected to exhibit significant shear elastic softening (−40%) compared to TiN compound, making them potential candidates for applications where material toughness is a requisite. Sangiovanni et al [15,16] and Petrman and Houska [13] have shown that this ductility trend increases with VEC in ternaries TMN, the best results being obtained for Mo-and W-based alloys. On the contrary, Ti 1 − x Al x N alloys evolve towards more brittle behavior with increasing Al content (see Fig.…”

“…We have used the Hill average, which is an arithmetic average of Reuss and Voigt estimates (see e.g., Ref. [13]) for the calculation of G. Fig. 1a displays the dimensionless quantities c 12 /c 11 versus c 44 /c 11 , commonly referred as a Blackman diagram [33], for the three ternary systems considered.…”

“…Many scientific advances have led to significant improvement of their hardness or thermal stability by fine tuning the micro-, nano-structure and chemical composition. Several successful approaches include phase stability tuning [1,2], interface design (superlattices, nanocomposites) [3][4][5][6][7], or multicomponent alloying [8][9][10][11][12][13][14][15][16][17][18][19][20]. A major challenge in materials science is to develop not only hard but also tough coatings, in order to prevent brittle failure when these materials are solicited by external stresses.…”

“…Theoretical studies are now routinely employed to explore complex alloy systems (ternary or quaternary) and identify the most promising candidates, based on elastic constant calculations [13][14][15][16][17][18][19]. Recently, Sangiovanni et al [15,16] have contributed to a better understanding of thin film toughening from ab initio calculations in TiN-and VNbased ternary alloys with cubic NaCl structure and found that increasing the valence electron concentration per unit formula (VEC) facilitates dislocation glide.…”

Novel strategy for low-temperature, high-rate growth of dense, hard, and stress-free refractory ceramic thin films

“…3,[11][12][13][14][15][16][17][18] Here, we demonstrate a new strategy for synthesizing highhardness, low-stress ceramic thin films at low growth temperatures (T s 120 C) based upon reactive hybrid high-power pulsed and dc magnetron co-sputtering (HIPIMS/DCMS) with synchronized substrate bias [19][20][21] with synchronized substrate bias in which a small concentration of a high-mass metal element, with a low first-ionization potential IP 1 , is provided during HIPIMS pulses. As an example of this approach, we deposit cubic NaCl-structure TiN by high-rate DCMS from a Ti (47.88 amu) target and add TaN to form a dilute solid solution (TiN and TaN exhibit complete solid solubility) 22 using HIPIMS/DCMS co-sputtering from a Ta (180.95 amu) target in mixed Ar/N 2 discharges. A negative substrate bias V s is applied in synchronous with the metal-ion portion (2% duty cycle) of each HIPIMS pulse.…”