This study concentrates on describing effects of laser heat treatment of Monel 400 and laser alloying its surface with boron. Surfaces without and with initial boron layers of two different thicknesses (100 and 200 μm) were processed using diode laser. Laser beam power density was constant and equal to 178.3 kW/cm². To determine the influence of laser beam scanning velocity on final properties of treated surfaces, laser beam scanning velocity was set on four different values: 5, 25, 50, and 75 m/min. Microstructures of pure Monel 400 and Monel 400 alloyed with 100 μm boron content are composed of dendrites. Areas laser alloyed with 200 μm boron layer contain mainly nickel borides. Boron addition in Monel 400 surface results in microhardness increase in which the level depends on boron content and the laser beam scanning velocity. Increasing the thickness of initial boron layer and speeding up the laser beam lead to obtain higher microhardness. On the other hand, areas laser alloyed with 200 μm boron layer using laser beam scanning velocity equal to 75 m/min contain deep cracks which propagate from the surface through the produced layer. Furthermore, it was found that the depths of laser heat-treated areas depend significantly on the boron content. As the result of differences in thermal properties between Monel 400 and boron, depth of re-melted zones in some conditions does not lower with increasing laser beam scanning velocity.

In this study, a nickel-based superalloy, Waspaloy, was laser heat treated with diode laser. Single laser tracks were manufactured with different laser beam power densities between 63 and 331 kW/cm², and scanning laser beam speed ranged from 5 to 100 m/min. It was found that laser heat treatment of Waspaloy causes decrease in material hardness—the microhardness in laser tracks is about 300 HV0,1 while the microhardness of substrate is ranged from 300 to 600 HV0,1—which is a positive phenomenon for laser-assisted machining of investigated material. Impacts of laser heat treatment parameters on laser tracks properties were identified for obtaining multiple laser tracks with the most homogenous thickness. Moreover, roughness of heated layers was measured to specify surface quality after laser heat treatment. Multiple laser tracks were produced using different scanning laser beam speed and distances between laser tracks ranged from 0.125 to 1 mm. It was found that if scanning laser beam speed is 75 m/min and distance between laser tracks is equal to or lower than 0.25 mm, in microstructures of multiple laser tracks, cracks are occurring. The most suitable laser heat parameters for obtaining heated layers, and which can be used for laser-assisted machining, were identified as laser beam power density 178.3 kW/cm², scanning laser beam speed 5 m/min, and distance between laser tracks 0.125 mm.

In this research, Monel metal was laser heat-treated for microstructural, microhardness and roughness investigation. The treatment is an initial stage for welding Monel without additional material for structural elements. The treatment was carried out with diode laser TruDiode 3006 which allows to reach a power of 3 kW. The material was treated with a constant laser beam power, equal to 1400 W, and four different laser beam velocities: 5, 25, 50 and 75 m/min. The distance between single laser tracks was 0,5 mm in every experimental series. It was found that laser heat treatment of Monel does not influence its hardness. The depth of melted areas is decreasing with an increasing laser beam velocity. The melted area manufactured with laser beam velocity equal to 5 m/min is about 350 μm. Increasing the laser beam velocity to 75 m/min causes depth reduction to about 100 μm. The melted areas are built with column crystals oriented in the direction of heat dissipation perpendicular to the heating direction.

The paper presents the study results of a laser cladding process of C45 steel using powder mixtures. The aim of this study was to investigate the microstructure, X-ray diffraction (XRD), chemical composition (EDS), microhardness, corrosion resistance and wear resistance of the newly obtained coatings. Modified coatings were prepared using laser cladding technology. A 1 kW continuous wave Yb:YAG disk laser with a powder feeding system was applied. Two different powder mixtures as well as various laser beam parameters were used. The first powder mixture contained Fe–B, and the second mixture was Fe–B–B₄C–Si. Two values of laser beam power (600 and 800 W) and three values of scanning speed (600, 800, and 1000 mm/min) were applied during the studies. As a result of the influence of the laser beam, the zones enriched with modifying elements were obtained. Based on the results of XRD, the presence of phases derived from borides and carbides was found. In all cases analyzed, EDS studies showed that there is an increased content of boron in the dendritic areas, while there is an increased silicon content in interdendritic spaces. The addition of B₄C and Si improved properties such as microhardness as well as wear and corrosion resistance. The microhardness of the coating increased from approx. 400 HV to approx. 1100 HV depending on the laser parameters used. The best corrosion resistance was obtained for the Fe–B–B₄C–Si coating produced using the highest laser beam scanning speed. An improvement in wear resistance can be seen after wear tests, where the weight loss decreased from about 0.08 g to about 0.05 g.