Purpose: This paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser technologies are increasing constantly. A specific laser treatment can modify the surface energy of copper and affect the wetting properties. Design/methodology/approach: The surfaces of copper plates were treated using an Nd:YAG laser with varying laser powers. After laser surface treatment, wetting experiments were performed between the copper plates and SAC305 lead-free solder paste. The effect of laser treatment on copper surface was analysed using optical microscopy and scanning electron microscopy (SEM). Findings: The experimental results showed that the wetting contact angles changed with the variation in laser power. Furthermore, it means that the surface energy of copper plates was changed by the laser treatment. The results demonstrated that the contact angles also changed when a different soldering paste was used. Originality/value: Previous laser surface treatment can be a possible way to optimize the wettability between solders and substrates and to increase the quality of the soldered joints.

Laser-based additive manufacturing (AM) of Ti–6Al–4V alloy has garnered increasing significance for its application in components within transportation systems. A notable advantage over conventional steel structures lies in the reduction of specific weight. Employing a layer-by-layer manufacturing approach enables the production of complex geometries, facilitating faster and cost-effective personalized part manufacturing with reduced material waste compared to conventional methods. Post-processing plays a crucial role between the AM process and the utilization of the part, influencing its strength properties and porosity. Heat treatment emerges as a viable option to alter the final part's properties. Despite its advantages, the AM of Ti–6Al–4V parts is still a rather expensive technology because of the costs of equipment, materials and postprocessing. Postprocessing (surface and heat treatment) cannot be avoided for cost reduction since the mechanical properties of the as-printed state are not favourable for the applications. However, we can decrease the costs of manufacturing by the reduction of auxiliaries for example the use of inert gas during annealing. The question that we expect an answer to from our investigation is whether there are any significant differences in mechanical properties between heat treatment in an inert atmosphere or without protection. Another question is that in the case of annealing without an inert atmosphere, the used micro-glass blasting is suitable for removing the oxide layer. The mechanical examinations covered conventional tensile tests and hardness measurements. The depth distribution of oxygen was investigated by Glow Discharge Optical Emission Spectrometry (GDOES) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (EDS).

Laser-based additive manufacturing (AM) of Ti-6Al-4V has become increasingly important for use in components of transportation devices. The most significant advantage over conventional steel structures is the reduction in specific weight. Comp...

This study investigates the mechanical behavior of Ti6Al4V components produced via laser-based powder bed fusion of metals (PBF-LB/M), with a focus on the effects of build orientation, heat treatment, and machining. Destructive testing methods—including tensile, Charpy impact, bending, and Poisson’s ratio measurements—were employed to evaluate mechanical properties under various conditions. Stress-relief heat treatment reduced residual stresses and resulted in a moderate decrease in strength. Compared to non-heat-treated specimens, the 0.2% offset yield strength decreased by approximately 20–100 MPa (≈ 2–9%), while ultimate tensile strength showed a similar reduction, remaining in the range of about 1100–1250 MPa. Machining had no significant influence on yield or tensile strength, with differences below 100 MPa, less than 8–9% of the measured strength values. Build orientation showed minimal effect on tensile properties, with all values are within an approximately 150 MPa range, which represents about 12–14% variation across orientations. Poisson’s ratio ranged from 0.29 to 0.33. Heat treatment and machining the V-notch also increased Charpy impact energy. Bending strength was slightly higher for XZ and XY orientations (≈ 2300–2600 MPa) than for Z-oriented specimens, while counter-deformation reduced bending strength by less than 5%. Additional post-processing techniques such as glass blasting and counter-deformation had limited impact. These findings highlight how strategic process optimization can improve the performance and efficiency of PBF-LB/M manufactured Ti6Al4V parts, making them suitable for demanding industrial applications.

Two kinds of phase stabilization mechanism are discussed and compared: the first is characteristic of the formation of bulk amorphous alloys, in which the high supercooling ability of multicomponent liquids is responsible for the glassy phase stabilization. Here the hindered nucleation of crystalline phases is the center phenomenon. The origin of this hindering is the slowing atomic mobility in the supercooling melt. In contrast the melt supercooling is negligible during the high entropy alloy formation. It is believed that stability of the crystalline single fcc phase is the consequence of the characteristic of high configurational entropy at high temperatures. However, the significance of this entropy-dominated stabilization is overestimated in several references. It has been concluded that transition metal contraction (arising from the d electron participation in the overall bonding state) does also contribute to the high temperature stability of fcc single phase in the high entropy alloys.