Papers by Keyword: Laser Alloying

Abstract: The present research shows the possibility of using an ytterbium nanosecond pulsed fiber laser for wear resistance improvement of carbon and alloy steels. The wear test was performed in accordance with the block-on-ring scheme with dry sliding friction on a friction machine. Surface dispersing/alloying was carried out from a boron carbide paste. This leads to a significant wear resistance improvement of steels. It was revealed that the mass loss during wear test reduced by several times after laser treatment compared to the non-treated samples. The wear mechanism differs depending on the type of steel and largely refers to their microstructure and composition. The tribo-oxide layer forms during the wear test.

Abstract: Two new parameters – reduced wear and reduced integral microhardness of the modified surface layer was used to evaluate the effectiveness of surface hardening technologies. The existence of a correlation between the entered parameters is shown, the regression equation is obtained based on the analysis of experimental data of the wear of a tool made of steel CrWMn and U10 treated with a laser with coatings in the reflow mode. We construct the functional dependence of tool wear on this parameter.

Abstract: The scope of the work covers the development of the relationship between the chemical composition of surface-modified aluminium and its mechanical properties. This article presents the impact of laser alloying with ZrO powder on the microstructure and mechanical properties of pure aluminium. In order to study the phenomena occurring during the laser alloying process, microstructural studies were carried out using optical microscopy. Additionally, the properties of the obtained alloy were tested - abrasion resistance and hardness measured at low load force. As a result of the alloying process, three distinct zones were identified: the remelting zone (RZ), the diffusion zone (DZ) and the heat affected zone (HAZ). The surface modification resulting from laser alloying increases the hardness and abrasion resistance of the material.

Abstract: Development and implementation of new methods of high-energy surface treatment of structural steels is one of the priorities of modern materials science One of the urgent problems of power engineering is the development of effective processing technologies that allow parts to provide the required properties of working surfaces. The use of laser technologies helps to increase wear resistance, corrosion resistance, reduce the duration of chemical and thermal treatment time and other technological characteristics that can improve the quality, durability and efficiency of parts, increase economic and environmental effects.

Abstract: Titanium alloys due to their low density and high mechanical properties are a group of materials that are being used willingly nowadays. A promising method of titanium heat treatment is laser surface alloying. Process parameters like laser beam power, its transverse speed, amount of alloying elements and shield gas, have influence on the material. Different chemical composition and morphology can be achieved resulting in a change of properties on the surface of the material. The paper presents the investigation of titanium GRADE 1 processed with iron‐nickel powder using laser alloying. The treatment was performed using a high power diode laser. Different laser beam power values were used.

Abstract: Laser surface treatment is at present one of up-to-date methods for surface layer engineering, in this technique into the matrix material are introduced some amount of alloying additives. So the surface layer is obtained in form of composite material consisting of ceramic particle powders with different properties influencing the surface layer appliance possibilities. Using the technology it is possible to obtain a layer revealing a structured structure consisting of the heat affected zone (HAZ), transition zone (TZ) and remelted zone (RZ), as well as the substrate material. The laser is without cracks and defects as well as has with a slightly higher hardness value compared to the raw substrate material. The used laser power range is set in the range between 1.0 to 2.5 Kw, with the laser scan rate of the beam head in a range between 0.25-0.75 m/min, depending of the applied laser power and material used for alloying.This study was conducted to determine the effect of carbide on oxide ceramic powders addition on the microstructure and mechanical properties their changes and enhancement possibilities during a rapid solidification process of the remelted surface layer. The investigation should help to use this laser treatment technology for alloying of ceramic powder particles into the surface of light alloys, especially magnesium and aluminium. The scientific reason of this work is the usage of High Power Diode Laser (HPDL) for improvement of aluminium`s mechanical properties, especially the surface hardness and war resistance.There was found during the investigations and analysis of the results that, the obtained surface layer is without cracks and defects as well as with a relatively higher hardness compared to the raw material, after standard heat treatment. The hardness value increases according to the laser power used so that the highest power applied gives the highest hardness value in the remelted layer, similar relation can be found in the wear resistance parameters, which increases also with increasing laser power.The findings of the investigations allows to state, that the distribution of the used ceramic particles is generally satisfied, especially the carbide powder was confirmed in the alloys matrix, the particles are mainly present in the upper part of the surface layer or in the bottom zone of the remelted area. The hardness value increases in general according to the laser power used and the highest power results with the highest hardness value in the surface layer. The main aim of this work is to investigate and determine the effect of HPDL remelting and alloying on the cast Al-Si-Cu and Mg-Al-Cu cast aluminium and cast magnesium alloys micro structure for possible application in real working conditions mainly for light metal constructions as well as in many branches of the industry like automotive and rail transportation.

Abstract: The paper presents the effect of alloying with WC and TaC powders on structure and mechanical properties of the X40CrMoV5-1 steel surface layer using the HPDL (High Power Diode Laser). The metallographic investigations on light microscope show that during alloying the X40CrMoV5-1 hot work tool steel with the WC and TaC powder the obtained run face is characteristic of the high roughness, multiple pores, irregularity, and flashes at the borders. The changes of the surface layers hardness formed as a result of alloying with ceramic powders containing carbides are accompanied with the increased tribological properties. The microstructure of the alloyed layers which were formed on the surface of the investigated hot work steel was examined using optical microscope. The tribological wear relationships using pin-on-disc test were specified for surface layers subject to laser treatment, determining the friction coefficient, and mass loss of the investigated surfaces.

Abstract: Advanced industrial applications require materials with special surface properties such as high hardness and high wear resistance. In this study, copper substrate samples where coated by Fe-Si by using thermal evaporation technique under high vacuum, then subjected to surface laser treatment by using 720 watt CO₂ laser beam. The purpose was to perform local alloying in the form of surface network of four tracks (each two are parallel and perpendicular to the other two) to produce a good thermal and electrical properties bulk material with reasonable surface hardness properties. The morphological features of the subsurface laser treated layers and their mechanical properties (microhardness) have been studied on oblique sections through the laser fused tracks. The results show that there were an intensive re-evaporation of the coating material, probably because of the high laser power density applied and the use of deep vacuum during the laser surface alloying process. Generally hardness recorded to be increased in the laser-fused tracks locations, but the bottom of the laser fused tracks showed a number of spherical voids causing a drastic decrease in the hardness values. The middle parts of the tracks showed columnar structure and elevated hardness values.

Abstract: To improve the service life of roller, a kind of alloying powder materials with CeO2 was designed. And the surface of roller was alloyed by a 5kW CO2 laser. The effect of CeO2 on microstructure and properties was studied by means of OM, Micro-hardness Testing Machine, Friction and Wear Tester. The experimental results indicate that addition of CeO2 into coating materials can refine and purify microstructure. Microstructure in alloying layer is coarse without CeO2, when CeO2 is up to 2.0wt.%, microstructure in alloying layer becomes finest. And microhardness and wear resistance become largest.

Abstract: AZ31 magnesium alloy preset SiC-316L powder by laser alloying on the surface treatment. The organizational structure and composition of alloying layer material by XRD, SEM and EDS phase were analyzed. The results show that the alloying layer surface has roughness, lap in good condition, no pilling, pores and cracks defect, etc. Alloying layer is mainly composed of the original phase Mg, Fe, SiC and the oxides of MgO and SiO2. The columnar grain zone perpendicular to the interface and pointing to the alloyed layer. It is formed in the bottom of the alloyed layer and the interface zone of magnesium alloy substrate.