Effects of pre-treatments on aging precipitates and corrosion resistance of a creep-aged Al–Zn–Mg–Cu alloy

Cold expansion technology of connection holes in aircraft structures: A review and prospect

Effect of pre-strain on creep aging behavior of 2524 aluminum alloy

Modeling of strain hardening and creep behaviour of 2024T3 aluminium alloy at room and high temperatures

Creep-aging forming, combining both the aging treatment and forming process, has recently drawn much attention of researchers. In this study, the effects of creep-aging processing on the corrosion resistance and mechanical properties of a typical Al–Cu–Mg alloy (2024 aluminium alloy) are investigated by electrochemical corrosion, exfoliation corrosion and uniaxial tensile experiments. The results show that the corrosion resistance and mechanical properties of the studied Al–Cu–Mg alloy are strongly sensitive to the creep-aging processing parameters. The creep-aging processing can change the dimension and density of nanoprecipitates, which greatly affects the corrosion resistance and mechanical properties of the studied Al–Cu–Mg alloy. With the increase of creep-aging temperature, the corrosion resistance and the elongation decrease, while the yield strength and ultimate tensile strength increase. For the materials creep-aged in “under aging” and “peak aging” conditions, the applied stress can increase the ultimate tensile strength, but deteriorate the corrosion resistance.

Effects of creep-aging processing on the corrosion resistance and mechanical properties of an Al–Cu–Mg alloy

This review paper is devoted to the slide burnishing (SB) of metal components—state-of-the-art, achievements and perspectives. SB belongs to the group of static methods for mechanical surface treatment used largely in aerospace, automotive and other industries. By means of the plastic deformation of the surface layers, the surface integrity (SI) of the respective component is improved greatly in terms of minimum roughness, micro-hardness and introduced residual compressive stresses. As a result, fatigue crack resistance, crack corrosion resistance, wear resistance and corrosion resistance increase dramatically. The main feature of SB is the sliding friction contact between the deforming element and the surface being treated. Using the differential-morphological method, an integrated classification of the static methods is created and the area of SB is outlined. The proposed morphological matrix, which can be expanded and supplemented contains existing burnishing methods as well as combinations of elements and interactions that can be used to synthesize new burnishing methods and tools. In addition, a literature review of the publications devoted to SB has been conducted. Further, an analysis of the published studies on different criteria has been carried out and graphic visualizations of the statistical results have been made. On this basis, relevant conclusions have been made and the directions for future investigations of SB have been outlined.

Slide burnishing—review and prospects

A finite element simulation of the spherical mandrelling process of holes with cracks

Slide burnishing (SB) is a static mechanical surface treatment based on the severe plastic deformation of the surface for which the contact between the deforming element and the surface being treated is sliding friction. SB improves the surface integrity of metal structural and machine components dramatically. This paper is devoted to improving the fatigue strength of 41Cr4 steel hourglass-shaped specimens subjected to SB with a spherical-ended deforming diamond via different combinations of basic governing parameters. Since the residual compressive stresses introduced play a significant role for the fatigue behavior of the burnished components, a comprehensive parametric study of the SB process was conducted using fully coupled thermal-stress finite element (FE) simulations. The FE model’s adequacy was proven via comparison of the FE results for the residual stresses with X-ray diffraction measurements. The results obtained show that the diamond radius and the burnishing force have the strongest effects on the residual stresses, which, in turn, have a significant influence on the fatigue strength, respectively, fatigue life. An extensive experimental investigation of the effect of the selected SB basic parameters on the fatigue limit of the slide burnished specimens was carried out using Locatti’s method. The latter is based on the Palmgren–Miner linear damage hypothesis, which is a particular case of a general cumulative damage theory. A planned experiment was carried out, with the governing factors changed among four levels. Regression analysis of the experimental results was carried out, and a model for predicting the fatigue limit was obtained. Based on the model obtained, a one-purpose optimization was carried out using a genetic algorithm. By means of the optimal basic parameters, the fatigue limit of the processed specimens was increased by 22.7%—from 440 to 540 MPa. The fatigue life increased more than 100 times over after SB with the optimal basic parameters.

M. D. Ichkova

Papers

Modeling of strain hardening and creep behaviour of 2024T3 aluminium alloy at room and high temperatures

Slide burnishing—review and prospects

A finite element simulation of the spherical mandrelling process of holes with cracks

Improvement in fatigue strength of 41Cr4 steel through slide diamond burnishing