Mechanical and tribological characteristics of laser-deposited nickel-containing powders on chromium steels

This paper presents the results of a study of various processing modes during the laser surfacing process. Various grades of steel were used as samples, and the resulting coatings were based on two grades of powders. The microhardness values were obtained both for the main steel material and for the coatings obtained on the samples. The values of the friction coefficients of the coatings are obtained, on the basis of which the graphs of standard deviations are constructed. The results are summarized using graphs and figures.

Investigation of physical, mechanical and tribological properties of corrosion-resistant steel with laser surface surfacing of WC100Co4Cr

The article investigated the effect of laser surfacing of WC100Co4Cr powder on the surface of corrosion-resistant steel on hardness, tensile strength and yield strength, coefficient of friction and the amount of wear of products made of alloy structural cryogenic steel. The SVAROG-1-5DR laser complex (Russia) was used for laser processing. Various modes of surface laser surfacing were set. For this purpose, the power of the laser radiation, the speed of movement of the laser beam relative to the treated surface and the focal length were varied. The measurement of physical, mechanical and tribological characteristics was carried out using the equipment of the company “CSM Instruments” (Switzerland). The structure of the alloy was studied by metallography and X-ray diffractometry. The results showed a significant increase in hardness, tensile strength and yield strength and a decrease in the coefficient of friction.

Effect of laser surfacing on the microstructure and mechanical properties of ultrasonic welded NiTi joints

In the present work, the effects of laser surfacing aiming at modify the surface roughness on NiTi sheets prior to the application of ultrasonic welding (USW) were investigated. Three different configurations joining original and laser surfaced specimens were performed: original/original (referred as O/O), original/treated (referred as O/T); treated/treated (referred as T/T). The influence of surface roughness on the interface formation, diffusion, and mechanical behavior was investigated. It is observed that when both bonding surfaces becomes rougher (T/T configuration), the joint strength is the highest, followed by both smooth bonding surfaces (O/O configuration), and the strength of the joint is the lowest when only one of the bonding surfaces was roughened (O/T configuration), which is related to the degree of plastic deformation at the joining interface. The main joining mechanism of NiTi to the Al interlayer was a metallic bond caused by shear plastic deformation and formation and growth of micro welds at the joining interfaces. Laser surfacing facilitates the metallic bonding, which is directly reflected in the change of the thickness of the Al interlayer after USW. This also helps to produce mechanical interlocking at the interface, although there is no significant difference in the elemental diffusion. Interfacial failure occurred in all joints tested under different surface contact conditions and exhibited ductile-like fracture characteristics.

RESEARCH AND DEVELOPMENT OF THE TECHNOLOGY FOR RESTORING THE BLADES OF THE GAS TURBINE ENGINE AFTER OPERATION BY LASER SURFACING

The paper presents the research and development of the technology for restoring the blades of a gas turbine engine made of ZhS6U alloy after operation by laser pulse surfacing. Metallographic examination and control by the luminescent method at the places of surfacing were carried out. A technology for eliminating defects that occur on the blades during operation has been developed and tested.