scholarly journals Residual stresses in surface layers and coatings

2021 ◽  
Vol 2144 (1) ◽  
pp. 012011
Author(s):  
A A Ashmarin ◽  
A A Lozovan ◽  
S Ya Betsofen ◽  
V S Moiseyev ◽  
E P Kubatina ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Elastic Anisotropy ◽  
Standard Technique ◽  
Metal Alloys ◽  
Ion Nitriding ◽  
Surface Layers ◽  
Refractory Coatings ◽  
Mechanisms Of Formation ◽  
Heat Shielding ◽  
Methods Of Measurement

Abstract Methods of measurement and mechanisms of formation of residual stresses in the surface layers of metal alloys after ion nitriding, as well as in heat-shielding and refractory coatings are considered. Examples of the application of a technique based on the peculiarities of elastic anisotropy for measuring residual stresses in heterogeneous surface layers, for which the standard technique of diffraction tensometry “sin2Ψ” is not applicable, are given.

Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

2011 ◽  
Author(s):  
Yuriy Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Highway Bridges ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

Structural transformation and residual stresses in surface layers of α + β titanium alloys nanotextured by femtosecond laser pulses

2014 ◽  
Vol 119 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Yu. R. Kolobov ◽  
E. V. Golosov ◽  
T. N. Vershinina ◽  
M. V. Zhidkov ◽  
A. A. Ionin ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Residual Stresses ◽  
Titanium Alloys ◽  
Structural Transformation ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Surface Layers

scholarly journals Explosive and thermochemical treatment of multi-layer metallic composites

2019 ◽  
pp. 51-56
Author(s):  
Jerzy Nowaczewski ◽  
Milena Kita ◽  
Justyna Świeczak ◽  
Jacek Rudnicki
Keyword(s):  
Cross Sections ◽  
Intermediate Phase ◽  
Intermetallic Layer ◽  
Thermochemical Treatment ◽  
Ion Nitriding ◽  
Surface Layers ◽  
Before And After ◽  
The Individual ◽  
Current Systems ◽  
Composite Samples

The paper describes methods for the explosive hardening of metals which were performed with a view to increasing the hardness of previously obtained composites, as well as treatment of their surface layers to increase the efficiency of further thermochemical treatment. Typical systems for explosive hardening of metals and the construction of current systems, are discussed. The resulting effects of explosive hardening are illustrated with before and after diagrams of microhardness distributions in cross-sections of the processed composites hardening. In a further processing stage, the tested composite samples were subjected to ion nitriding. As a result of this process, in addition to the typical increase in hardness of the individual layers, an intermediate phase with a distinctly higher hardness was observed in the junction zone. Preliminary analysis of the photographs and the results from a scanning electron microscope (SEM) with an energy dispersive spectroscopy (EDS) attachment suggests that the particularly beneficial properties of the composites are attributed to the presence of the intermetallic layer.

Properties of the surface of structural materials in the area of a barcode formed under the action of laser radiation

2021 ◽  
Vol 1 ◽  
pp. 15-24
Author(s):  
Yu.R. Kolobov ◽  
◽  
A.E. Ligachev ◽  
Keyword(s):  
Laser Radiation ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Structural Materials ◽  
Metal Alloys ◽  
Experimental Investigations ◽  
Structure And Properties ◽  
Surface Layers ◽  
Continuous Laser ◽  
Near Surface

A review of experimental investigations of changes in the structure and properties of the surface and near-surface layers of various materials (steels, metal alloys, ceramics and graphite) in the area of a barcode applied by continuous laser radiation and short (nanosecond) and ultrashort (femto- and picosecond) laser pulses.

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