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Influence of Zr on structure, mechanical and thermal properties of Ti-Al-N.

Chen L, Holec D, Du Y, Mayrhofer PH - Thin Solid Films (2011)

Bottom Line: Here, we study the effect of Zr addition on structure, mechanical and thermal properties of Ti(1-x)Al(x)N based coatings under the guidance of ab initio calculations.Increasing the Zr content from z = 0 to 0.17, while keeping x at ~ 0.5, results in a hardness increase from ~ 33 to 37 GPa, and a lattice parameter increase from 4.18 to 4.29 Å.Furthermore, Zr assists the formation of a dense oxide scale.

View Article: PubMed Central - PubMed

Affiliation: Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Leoben, 8700, Austria.

ABSTRACT
Multinary Ti-Al-N thin films are used for various applications where hard, wear and oxidation resistant materials are needed. Here, we study the effect of Zr addition on structure, mechanical and thermal properties of Ti(1-x)Al(x)N based coatings under the guidance of ab initio calculations. The preparation of Ti(1-x-z)Al(x)Zr(z)N by magnetron sputtering verifies the suggested cubic (NaCl-type) structure for x below 0.6-0.7 and z ≤ 0.4. Increasing the Zr content from z = 0 to 0.17, while keeping x at ~ 0.5, results in a hardness increase from ~ 33 to 37 GPa, and a lattice parameter increase from 4.18 to 4.29 Å. The latter are in excellent agreement with ab initio data. Alloying with Zr also promotes the formation of cubic domains but retards the formation of stable wurtzite AlN during thermal annealing. This leads to high hardness values of ~ 40 GPa over a broad temperature range of 700-1100 °C for Ti(0.40)Al(0.55)Zr(0.05)N. Furthermore, Zr assists the formation of a dense oxide scale. After 20 h exposure in air at 950 °C, where Ti(0.48)Al(0.52)N is already completely oxidized, only a ~ 1 μm thin oxide scale is formed on top of the otherwise still intact ~ 2.5 μm thin film Ti(0.40)Al(0.55)Zr(0.05)N.

No MeSH data available.


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Hardness, H, indentation modulus, E, and residual stresses, σ, of Ti1-x-zAlxZrzN films as a function of z.
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f0015: Hardness, H, indentation modulus, E, and residual stresses, σ, of Ti1-x-zAlxZrzN films as a function of z.

Mentions: The shift of the XRD peak positions to lower 2θ angles indicate increasing lattice parameters from 4.18 to 4.19 to 4.23 to 4.31 Å with increasing ZrN mole fraction z for the films Ti0.48Al0.52N, Ti0.40Al0.55Zr0.05N, Ti0.39Al0.51Zr0.10N, and Ti0.34Al0.37Zr0.29N, respectively. These lattice parameters, obtained from powdered film samples after removing from their low alloy steel substrates, are in excellent agreement (maximum deviation of 0.2%) with the ab initio obtained lattice parameters of a = 4.184, 4.197, 4.238, and 4.320 Å for Ti0.50Al0.50N, Ti0.389Al0.556Zr0.056N, Ti0.389Al0.50Zr0.111N, and Ti0.33Al0.39Zr0.28N. Fig. 1 furthermore shows that the 111/200 peak intensity increases with increasing Zr content for the samples Ti0.40Al0.55Zr0.05N, Ti0.36Al0.47Zr0.17N, and Ti0.34Al0.37Zr0.29N, which is in agreement to our previous studies [3,16] and other reports [4,42] suggesting that with increasing Al content the 200 orientation is preferred. Stress measurements by the substrate-curvature method of films on Si substrates suggest increasing compressive stresses from around − 1.45 to − 3.53 GPa with increasing ZrN mole fractions z from 0 to 0.29, see Fig. 3.


Influence of Zr on structure, mechanical and thermal properties of Ti-Al-N.

Chen L, Holec D, Du Y, Mayrhofer PH - Thin Solid Films (2011)

Hardness, H, indentation modulus, E, and residual stresses, σ, of Ti1-x-zAlxZrzN films as a function of z.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117144&req=5

f0015: Hardness, H, indentation modulus, E, and residual stresses, σ, of Ti1-x-zAlxZrzN films as a function of z.
Mentions: The shift of the XRD peak positions to lower 2θ angles indicate increasing lattice parameters from 4.18 to 4.19 to 4.23 to 4.31 Å with increasing ZrN mole fraction z for the films Ti0.48Al0.52N, Ti0.40Al0.55Zr0.05N, Ti0.39Al0.51Zr0.10N, and Ti0.34Al0.37Zr0.29N, respectively. These lattice parameters, obtained from powdered film samples after removing from their low alloy steel substrates, are in excellent agreement (maximum deviation of 0.2%) with the ab initio obtained lattice parameters of a = 4.184, 4.197, 4.238, and 4.320 Å for Ti0.50Al0.50N, Ti0.389Al0.556Zr0.056N, Ti0.389Al0.50Zr0.111N, and Ti0.33Al0.39Zr0.28N. Fig. 1 furthermore shows that the 111/200 peak intensity increases with increasing Zr content for the samples Ti0.40Al0.55Zr0.05N, Ti0.36Al0.47Zr0.17N, and Ti0.34Al0.37Zr0.29N, which is in agreement to our previous studies [3,16] and other reports [4,42] suggesting that with increasing Al content the 200 orientation is preferred. Stress measurements by the substrate-curvature method of films on Si substrates suggest increasing compressive stresses from around − 1.45 to − 3.53 GPa with increasing ZrN mole fractions z from 0 to 0.29, see Fig. 3.

Bottom Line: Here, we study the effect of Zr addition on structure, mechanical and thermal properties of Ti(1-x)Al(x)N based coatings under the guidance of ab initio calculations.Increasing the Zr content from z = 0 to 0.17, while keeping x at ~ 0.5, results in a hardness increase from ~ 33 to 37 GPa, and a lattice parameter increase from 4.18 to 4.29 Å.Furthermore, Zr assists the formation of a dense oxide scale.

View Article: PubMed Central - PubMed

Affiliation: Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Leoben, 8700, Austria.

ABSTRACT
Multinary Ti-Al-N thin films are used for various applications where hard, wear and oxidation resistant materials are needed. Here, we study the effect of Zr addition on structure, mechanical and thermal properties of Ti(1-x)Al(x)N based coatings under the guidance of ab initio calculations. The preparation of Ti(1-x-z)Al(x)Zr(z)N by magnetron sputtering verifies the suggested cubic (NaCl-type) structure for x below 0.6-0.7 and z ≤ 0.4. Increasing the Zr content from z = 0 to 0.17, while keeping x at ~ 0.5, results in a hardness increase from ~ 33 to 37 GPa, and a lattice parameter increase from 4.18 to 4.29 Å. The latter are in excellent agreement with ab initio data. Alloying with Zr also promotes the formation of cubic domains but retards the formation of stable wurtzite AlN during thermal annealing. This leads to high hardness values of ~ 40 GPa over a broad temperature range of 700-1100 °C for Ti(0.40)Al(0.55)Zr(0.05)N. Furthermore, Zr assists the formation of a dense oxide scale. After 20 h exposure in air at 950 °C, where Ti(0.48)Al(0.52)N is already completely oxidized, only a ~ 1 μm thin oxide scale is formed on top of the otherwise still intact ~ 2.5 μm thin film Ti(0.40)Al(0.55)Zr(0.05)N.

No MeSH data available.


Related in: MedlinePlus