Microstructural aspects of fracture in nanolayered TiAlCrN thin films

2003 ◽  
Vol 795 ◽  
Author(s):  
A. E. Santana ◽  
A. Karimi ◽  
V. H. Derflinger ◽  
A. Schütze
Keyword(s):  
Thin Films ◽  
Grain Boundary Sliding ◽  
Enhancement Effect ◽  
Bilayer Thickness ◽  
Structural Modifications ◽  
Bilayer Films ◽  
High Resolution Tem ◽  
Boundary Sliding ◽  
And Control ◽  
Cathodic Arc

ABSTRACTThis paper studies the effects of bilayer thickness and chromium content on the microstructure and mechanical properties of nanolayered TiAlN/CrN thin films. By rotation of samples holder and control of targets activity, a variety of multilayers and chemically modulated thin films were grown on WC-Co substrates using cathodic arc PVD. Conventional and high resolution TEM showed that aluminum contributes to refinement of structure while chromium favors the formation of coarse columnar morphology. Consequently, TiAlN layers periodically interrupt the formation of columns in CrN layers in multilayer films, while in chemically modulated samples the columns are not interrupted leading thus to the formation of strongly columnar films. Both Cr content and bilayer thickness contribute to hardness enhancement. Effect of Cr arises from the formation of hard fcc-(CrAl)N phase to the detriment of softer wurtzite-like hcp-AlN. The contribution of bilayer thickness is explained by the grain refinement based on Hall-Petch effect and the formation of highly stressed columnar structures with (111) preferred orientation. Such structural modifications strongly influence crack modes and morphologies as observed using AFM and FIB cross-section of indents. Thin bilayer films exhibit well-organized straight cracks parallel to the contact edge between indenter and film, while large bilayer films show a network of discontinuous irregular mud cracks attributed to grain boundary sliding. Refinement of structure favours crack meandering and branching that prevents the propagation of large cracks with more dramatic effects.

In-situ observation of cooperative grain boundary sliding and migration in the nano-twinned nanocrystalline-Au thin-films

2020 ◽  
Vol 180 ◽  
pp. 97-102 ◽  
Author(s):  
Qizhen Li ◽  
Lihua Wang ◽  
Jiao Teng ◽  
Xiaolu Pang ◽  
Xiaodong Han ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
In Situ Observation ◽  
Boundary Sliding ◽  
Au Thin Films ◽  
And Migration

Novel Nanocrystalline Materials by Pulsed Laser Deposition

2000 ◽  
Vol 617 ◽  
Author(s):  
J. Narayan ◽  
A.K. Sharma ◽  
A. Kvit ◽  
D. Kumar ◽  
J.F. Muth
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Grain Boundary Sliding ◽  
Laser Deposition ◽  
Nanocrystalline Metal ◽  
Potential Applications ◽  
Novel Method ◽  
Boundary Sliding

AbstractWe have developed a novel method based upon pulsed laser deposition to produce nanocrystalline metal, semiconductor and magnetic material thin films and composites. The size of nanocrystals was controlled by interfacial energy, number of monolayers and substrate temperature. By incorporating a few monolayers of W during PLD, the grain size of copper nanocrystals was reduced from 160nm (Cu on Si (100)) to 4nm for a multilayer (Cu/W/Cu/W/Si (100)) thin film. The hardness increased with decreasing grain size up to a certain value (7nm in the case of copper) and then decreased below this value. While the former is consistent with Hall-Petch model, the latter involves a new model based upon grain boundary sliding.We have used the same PLD approach to form nanocrystalline metal (Ni, Co, Fe embedded in α-A12O3 and MgO) and semiconductor (Si, Ge, ZnO, GaN embedded in AIN and α-A12O3) thin films. These nanocrystalline composites exhibit novel magnetic properties and novel optoelectronic properties with quantum confinement of electrons, holes and excitons in semiconductors. We review advanced PLD processing, detailed characterization, structureproperty correlations and potential applications of these materials.

Grain Boundary Sliding in Thin Substrate-Bonded al Films

1993 ◽  
Vol 309 ◽  
Author(s):  
M. Prieler ◽  
H.G. Bohn ◽  
W. Schilling ◽  
H. Trinkaus
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Bulk Material ◽  
Grain Boundary Sliding ◽  
Systematic Investigation ◽  
Lattice Diffusion ◽  
Film Material ◽  
Thin Film Material ◽  
Si Substrates ◽  
Boundary Sliding

AbstractA systematic investigation of the anelastic relaxation of thin Al films on Si substrates has been carried out. It was found that both the relaxation in bulk and thin film material can be explained by a model involving glide of grain boundaries (GBs). The mass transport necessary for the glide occurs via GB diffusion in the thin films and via lattice diffusion in the bulk material the different behavior being due to the more of two orders of magnitude smaller grains in the films. Internal friction thus provides a technique to measure diffusional parameters of GB diffusion in thin films.

Grain Boundary Sliding in Thin Substrate-Bonded AL Films

1993 ◽  
Vol 308 ◽  
Author(s):  
M. Prieler ◽  
H.G. Bohn ◽  
W. Schilling ◽  
H. Trinkaus
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Bulk Material ◽  
Grain Boundary Sliding ◽  
Systematic Investigation ◽  
Lattice Diffusion ◽  
Film Material ◽  
Thin Film Material ◽  
Si Substrates ◽  
Boundary Sliding

ABSTRACTA systematic investigation of the anelastic relaxation of thin Al films on Si substrates has been carried out. It was found that both the relaxation in bulk and thin film material can be explained by a model involving glide of grain boundaries (GBs). The mass transport necessary for the glide occurs via GB diffusion in the thin films and via lattice diffusion in the bulk material the different behavior being due to the more of two orders of magnitude smaller grains in the films. Internal friction thus provides a technique to measure diffusional parameters of GB diffusion in thin films.

Strain Rate Dependent Behavior of Pure Aluminum and Copper Micro-Wires

2001 ◽  
Vol 695 ◽  
Author(s):  
P. A. El-Deiry ◽  
R. P. Vinci
Keyword(s):  
Thin Films ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Pure Aluminum ◽  
Grain Boundary Sliding ◽  
Dislocation Motion ◽  
Small Scale ◽  
Rate Dependent ◽  
Dependent Behavior ◽  
Boundary Sliding

ABSTRACTIn order to shed light on the role that grain boundaries and dislocations play in anelastic relaxation of thin films and small-scale structures, we measured the effective elastic moduli of 99.99% pure Al and Cu 10 m m diameter micro-wires in the as-received (drawn and slight tempered) and annealed states. Moduli were determined using microtensile tests at various strain rates (6.7x10-6s-1, 1.3x10-5s-1, 2.6x10-5s-1, 4.5x10-5s-1, 2.5x10-4s-1, 4.5x10-4s-1). Focused-ion beam scanning electron microscopy was used for imaging grain sizes. Results from the as-received wires are compared with the annealed wires to illustrate the effects of grain size and dislocation density on effective moduli, which closely relates to grain boundary sliding and dislocation motion, respectively. We conclude that microstructure is more significant than scale in inducing anelasticity in small-scale wires and, by extension, thin films.

Examination of Fracture Interfaces in Silicon Nitride

1975 ◽  
Vol 33 ◽  
pp. 60-61
Author(s):  
Nancy J. Tighe
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Slow Crack Growth ◽  
Ceramic Materials ◽  
Grain Boundary Sliding ◽  
Boundary Phase ◽  
Turbine Engines ◽  
Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

INTERNAL FRICTION PEAKS CONNECTED WITH GRAIN BOUNDARY SLIDING IN Al

1983 ◽  
Vol 44 (C9) ◽  
pp. C9-759-C9-764
Author(s):  
E. Bonetti ◽  
A. Cavallini ◽  
E. Evangelista ◽  
P. Gondi
Keyword(s):  
Internal Friction ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Boundary Sliding

Formation of Large, Orientation-Controlled, Nearly Single Crystalline Si Thin Films on SiO2 Using Contact Printing of Rolled and Annealed Nickel Tapes

2003 ◽  
Vol 762 ◽  
Author(s):  
Hwang Huh ◽  
Jung H. Shin
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
High Resolution ◽  
Amorphous Silicon ◽  
Tem Analysis ◽  
Contact Printing ◽  
Single Crystalline ◽  
High Resolution Tem ◽  
Lateral Crystallization ◽  
Si Films

AbstractAmorphous silicon (a-Si) films prepared on oxidized silicon wafer were crystallized to a highly textured form using contact printing of rolled and annealed nickel tapes. Crystallization was achieved by first annealing the a-Si film in contact with patterned Ni tape at 600°C for 20 min in a flowing forming gas (90 % N2, 10 % H2) environment, then removing the Ni tape and further annealing the a-Si film in vacuum for2hrsat600°C. An array of crystalline regions with diameters of up to 20 μm could be formed. Electron microscopy indicates that the regions are essentially single-crystalline except for the presence of twins and/or type A-B formations, and that all regions have the same orientation in all 3 directions even when separated by more than hundreds of microns. High resolution TEM analysis shows that formation of such orientation-controlled, nearly single crystalline regions is due to formation of nearly single crystalline NiSi2 under the point of contact, which then acts as the template for silicide-induced lateral crystallization. Furthermore, the orientation relationship between Si grains and Ni tape is observed to be Si (110) || Ni (001)

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