Laser surface texturing (LST) is a method to obtain micro-structures on the material's surface for improving tribological performances, wetting tuning, surface treatment, and increasing adhesion. The material selected for LST is AISI 430 ferritic stainless steel, distinguished by the low cost in manufacturing, corrosion resistance, and high strength at elevated temperature. The present study addresses the morphology of new pattern designs (crater array, ellipse, and octagonal shapes). The patterns are applied on the stainless-steel surface by a non-contact method with high quality and precision nanosecond pulsed laser equipment. The investigation of laser parameter influence on thermal affected area and micro-structures is accomplished by morphological and elemental analysis (SEM + EDX). The parameters of the laser micro-patterning have a marked influence on the morphology, creating groove-type sections with different depths and recast material features. From the SEM characterization, the highest level of recast material is observed for concentric octagon LST design. Its application is more recommended for the preparation of the metal surface before hybrid welding. Additionally, the lack of the oxygen element in the case of this design suggests the possible use of the pattern in hybrid joining.

Amorphous calcium carbonate particles with average diameter of 56 m have been coated with poly (vinyl acetate) to improve their adhesion to a thermoplastic polymer matrix such as high-density polyethylene.The resulting composite materials, obtained by compression moulding of the coated calcium carbonate filler and polyethylene matrix at 140 C present improved tensile strengths, in comparison with the reference material, obtained without poly (vinyl acetate) coating.The mechanical properties of the composite assembly have been modelled with Digimat-FE software, obtaining a satisfactory correlation between the experimental results and the simulated tensile strength.

Nowadays, there is an increasing demand for AISI 316 stainless steel for automotive, medical, aerospace, for tool manufacturing and for nuclear industry. Compared with continuous beam laser welding, pulse temporal shape, pulse duration and the repetition rate are fundamental parameters that have a direct influence on the quality on the welded joint [2]. The laser welding of AISI 316 stainless steel thin sheets by millisecond pulsed laser will be analysed within this research by addressing to pulsed laser parameters influence on the geometry and appearing of the welding joint. The influence of laser power, pulse duration and repetition rate were determined by tracking fusion lines on specimen’s plates and butt weld stainless steel welding were obtained by using the determined optimal welding parameters. All the parameters have a major influence on the geometrical appearance of the weld bead.

Laser-generated surface patterns provide the means for local mechanical interlocking between the joined materials, tunes the wettability of surfaces that come in contact, and generally are the main factor for bonding strength enhancement, especially between dissimilar materials. This paper presents the influence of different patterning overlays generated with a pulsed laser on the surface of stainless-steel sheets. For all experiments, an overlapping degree of 90% has been chosen between three different patterns, while the engraving speed, pulse frequency and number of passes have varied. The textured surfaces’ morphology was assessed through optical microscopy, and the roughness of the surfaces was correlated with the corresponding experimental parameters. The results have indicated promising insights for joining stainless steel to plastic materials, which is otherwise difficult to assess through usual welding techniques.

Due to its wide applicability in industry, devising microstructures on the surface of materials can be easily implemented and automated in technological processes. Laser Surface Texturing (LST) is applied to modify the chemical composition, morphology, and roughness of surfaces (wettability), cleaning (remove contaminants), reducing internal stresses of metals (hardening, tempering), surface energy (polymers, metals), increasing the adhesion (hybrid joining, bioengineering) and decreasing the growth of pathogenic bacteria (bioengineering). This paper is a continuation and extension of our previous studies in laser-assisted texturing of surfaces. Three different patterns (crater array-type C, two ellipses at 90° overlapping with its mirror-type B and 3 concentric octagons-type A) were applied with a nanosecond pulsed laser (active medium Nd: Fiber Diode-pumped) on the surface of a ferritic stainless steel (AISI 430). Micro texturing the surface of a material can modify its wettability behavior. A hydrophobic surface (contact angle greater than 90°) was obtained with different variations depending on the parameters. The analysis performed in this research (surface roughness, wettability) is critical for assessing the surface functionality, characteristics and properties of the stainless steel surface after the LST process. The values of the surface roughness and the contact angle are directly proportional to the number of repetitions and inversely proportional to the speed. Recommendations for the use of different texturing pattern designs are also made.

This literature overview could serve to further understand the processes involved and how to optimize the techniques for obtaining enhanced metal to-polymer hybrid joints. There were analysed: mechanical fastening, adhesive bonding, surface functionalisation and different kinds of welding. Using the laser welding technology, different types of joints could be produced, that are difficult to be achieved by conventional joining methods, such as adhesive-bonding, mechanical fastening and thermal pressing. The best performances were observed for surface functionalisation of the metallic part combined with laser welding.