Modification of the structure and properties of gradient nanocrystalline coatings Ti-Al- Si-Cu-N by annealing in vacuum

The nanocrystalline gradient coatings system Ti-Al-Si-Cu-N were annealed in the temperature range of 500– 1100°C. Their composition, structure, and mechanical properties were studied by methods of scanning and transmission electron microscopy, scratch test, and measurement of nanohardness. It is shown that the diffusion of substrate elements has a crucial impact on the heat-activated processes of structure recovery, the growth of crystal size and the properties of materials. This results in nanocomposite structure with high adhesion characteristics of the coatings

The structure and properties of single layer and gradient-layered coatings of the Ti-Al-Si-Cr-Mo-S-N system

Using the method of microprobe analysis and transmission electron microscopy, the influence of obtaining conditions upon particular elemental composition and growth structure coatings of Ti–Al–Si–Mo–S–N system was studied. The possibility of formation and characteristics of the structural and elastic-stress state single-layer coatings with nanoscale columnar or equiaxed grains and gradient-layered, combining two types of selected structure, was defined. On the basis of hardness, tribological properties and coating hardness, a conclusion was made about the relative prospects of its use as wear-resistant coatings with a nanocrystalline structure

Modification of the microstructure of TiN-based columnar coatings in indentation zones

The columnar structure of titanium nitride–based coatings deposited by magnetron sputtering is studied. The structure–phase state of the coatings is analyzed after deposition and in the indentation zone. The type of dislocation structure, the grain size, the subgrain size, the misorientations at boundaries, and their change during coating growth are determined. The detected decrease (several tens of percent) in the coating thickness under an indenter indicates plastic deformation of a coating. On a microscopic level, this deformation manifests itself in an increase in the density, the misorientation, and the nonequilibrium of boundaries

Structure of Ti-Al-Si-N gradient coatings

The microstructure, the stresses, and the elemental composition of Ti-Al-Si-N gradient coatings are studied by transmission electron microscopy and electron-probe microanalysis of thin foils prepared in the cross section of the coatings. As the concentration of the elements that alloy titanium nitride increases across the coating thickness, the structure of the coating changes from submicrocrystalline columnar grains to nanocrystalline grains. In these structural states, the structural characteristics (lattice parameter, lattice bending-torsion, crystal size, type of intragranular defect structure) and the residual stresses change. The magnitude and the sign of residual stresses change when the type of structural state changes

Microstructure and mechanical properties of V-4Ti-4Cr alloy as a function of the chemical heat treatment regimes

The regularities of the formation of a heterophase structure and mechanical properties of V–4Ti–4Cr alloy as a function of thermomechanical and chemical heat treatments are studied. The regimes of thermomechanical treatment which provide the formation of a heterophase structure with a homogeneous volume distribution of oxycarbonitride nanoparticles with a size of about 10 nm and an increase in the volume content and thermal stability of this phase and which provide an increase in the temperature of alloy recrystallization are developed. The formation of the heterophase structure results in a substantial (up to 70%) increase in the short-term high-temperature strength of the alloy at T = 800°C. The increase in the strength is achieved while keeping a rather high level of plasticity

The structure and properties of single layer and gradient-layered coatings of the Ti-Al-Si-Cr-Mo-S-N system

Using the method of microprobe analysis and transmission electron microscopy, the influence of obtaining conditions upon particular elemental composition and growth structure coatings of Ti–Al–Si–Mo–S–N system was studied. The possibility of formation and characteristics of the structural and elastic-stress state single-layer coatings with nanoscale columnar or equiaxed grains and gradient-layered, combining two types of selected structure, was defined. On the basis of hardness, tribological properties and coating hardness, a conclusion was made about the relative prospects of its use as wear-resistant coatings with a nanocrystalline structure

Modification of the structure and properties of gradient nanocrystalline coatings Ti-Al- Si-Cu-N by annealing in vacuum

The nanocrystalline gradient coatings system Ti-Al-Si-Cu-N were annealed in the temperature range of 500– 1100°C. Their composition, structure, and mechanical properties were studied by methods of scanning and transmission electron microscopy, scratch test, and measurement of nanohardness. It is shown that the diffusion of substrate elements has a crucial impact on the heat-activated processes of structure recovery, the growth of crystal size and the properties of materials. This results in nanocomposite structure with high adhesion characteristics of the coatings

Structural peculiarities of growth and deformation of Ti-Al-Si-Cu-N gradient-laminated coatings due to indentation

The composition, structure, properties and deformation behavior during the indentation of gradient-layered heterophase coatings of a Ti-Al-Si-Cu-N system were studied using scanning, transmission microscopy and hardness measurement techniques. The results showed the alteration of structural state characteristics-decreased crystal sizes and crystal lattice parameter and increased lattice bending-torsion-throughout the coating thickness, which changed depending on the elemental composition and the synthesis conditions. The work also studied the coating's fracture behavior and assessed the macroscopic plastic deformation of its separate layers. It was established that near the indenter's tip, the nanocrystalline structure experienced the formation of separate nanosized localized fracture areas that were connected by multiple branching cracks. It was shown that the deformation of nanocrystalline and submicrocrystalline layers may exceed dozens of percent, and more in magnitude, especially with increasing distance from the indentation tip in the case of a layer with a columnar structure. The characteristics of the microstructure of different coating layers in the indentation zone were studied. It was found that in the indentation zone under the indenter's tip, the deformation of layers with initially different structures led to equalization of the characteristics of their structural state and the similarity of a defective microstructure at the nanoscale level