A. V. Chumaevskii

Structure and tensile fracture of 1570C aluminum alloy

Both deformation and fracture tensile studies on orientation dependence of 1570C aluminum alloys samples with respect to rolling direction have been carried out. As revealed, the viscous fracture mechanism is more inherent to the samples with orientation transversal to the rolling direction while samples oriented along the rolling direction revealed quasi-brittle areas on the fracture surfaces. Despite practically the same level of the yield stress there is 10% difference I the ultimate stress.

AA2024 microstructural evolution after bidirectional friction stir processing

The microstructure of AA2024 sheet subjected to the multiple pass bidirectional friction stir processing (FSP) was studied. The experiments demonstrated the structural homogeneity of metal on the intersections between two perpendicular passes. The FSP process parameters suffer dramatic changes on the intersections as compared to those when processing the base metal. The FSP tool travel resistance is reduced when encountering the previously stirred metal due to different conditions of deformation and the tool-induced metal flow existing in the structurally modified stirring zones.

Friction-stir processed ultrafine grain high-strength Al-Mg alloy material

It was shown experimentally that both friction stir processing parameters and the workpiece thickness have their effect on structure and mechanical properties of the processed samples. Even the 10% deflection from the optimal values resulted in the essential mechanical strength reduction. It was observed that FSP showed a tendency to suppress the serrated yielding during the tensile testing.

High-strength friction stir processed dispersion hardened Al-Cu-Mg alloy

It was experimentally shown that optimal friction stir processing (FSP) parameters existed for Al-Cu-Mg alloy samples subjected to friction stir processing in the sense of obtained ultrafine metal strength and microstructure. FSP of this alloy resulted in the formation of a recrystallized grain zone. The deflection from optimal process parameters resulted in lower FSPed metal strength.

Compression strain-induced folding at intersecting deformation macrobands on the copper single crystals

Compression strain-induced surface pattern on copper single crystal faces was studied by means of optical, confocal laser and scanning electron microscopies. It was shown that apart from work-hardening effect of previously formed deformation macrobands there is a pure geometrical (size) effect which serves for changing the conditions for further deformation within the deformation macroband zones by folded structure formation.

Orientation dependence of compression deformation on 1570C aluminum alloy

The compression deformation orientation dependence of Al-Mg-Sc-Zr aluminium alloy has been studied. As shown, the compression axis orientation with respect to previous rolling direction changes the stress-strain curve behavior. The discontinuous yielding during compression deformation along the rolling direction of characterized by two types of serrations as compared to the only one type in case of deformation transversal to the rolling direction.

Mechanical strength characterization of three-component composite structural components

Mechanical strength characterization of structural components made of three-component composite material using additive manufacturing has been carried out. The deformation and fracture behaviour of two types was revealed. Mechanical strength characteristics of structural components have been determined in connection with the material properties.

Mechanical strength of additive manufactured carbon fiber reinforced polyetheretherketone

Mechanical properties of both pure and chopped carbon fiber reinforced polyetheretherketone samples have been carried out. It was shown that the reinforcement resulted in increasing the elasticity modulus, compression and tensile ultimate strength by a factor of 3.5, 2.9 and 2.8, respectively. The fracture surfaces have been examined using both optical and scanning electron microscopy.

Mechanical properties of three-component additive manufactured composites at elevated and cool temperatures

Elevated and cool temperature tensile tests on three-component composite materials made of carbon fibers, thermoplastic and thermosetting bonding agents have been carried out. The results of tests testify the increasing the composite strength at negative temperature –120°C and reducing it at elevated temperature +120°C. The low temperature fracture of samples resulted in formation of numerous small fragments by cracking and delamination in deformation. The high temperature tests produced numerous delaminated fibers.

Plastic strain arrangement in copper single crystals in sliding

Deformation of tribologically loaded contact zone is one of the wear mechanisms in spite of the fact that no mass loss may occur during this process. Generation of optimal crystallographic orientations of the grains in a polycrystalline materials (texturing) may cause hardening and reducing the deformation wear. To reveal the orientation dependence of an individual gain and simplify the task we use copper single crystals with the orientations of the compression axis along [111] and [110]. The plastic deformation was investigated by means of optical, scanning electron microscopy and EBSD techniques. It was established that at least four different zones were generated in the course of sliding test, such as non-deformed base metal, plastic deformation layer sliding, crystalline lattice reorientation layer and subsurface grain structure layer. The maximum plastic strain penetration depth was observed on [110]-single crystals. The minimum stability of [111]-crystals with respect to rotation deformation mode as...