Complex phase steels, known for their high levels of conformability, energy absorption, and deformation capacity, are among the more advanced high-strength steels. The objective of this study was to compare the mechanical properties of CPW 800-class complex phase steels, with and without laser welding. The analysis involved determining tensile strength, yield strength, elongation, and area reduction through tensile tests, in scenarios both with and without laser welding. Additionally, the number of cycles was assessed via fatigue tests, and absorbed energy was measured using impact tests. The non-parametric Kruskal–Wallis test, at a 5% significance level, revealed that tensile strength, yield strength, area reduction, and absorbed energy were statistically similar regardless of laser welding. However, elongation and the number of cycles showed significant differences. The fractured surface from axial fatigue tests exhibited ductile characteristics, with the additional presence of dimples or alveoli.

The future of the automotive industry appears to hinge on the integration of dissimilar materials, such as aluminum alloys and carbon steel. However, this combination can lead to galvanic corrosion, compromising the structural integrity. In this study, laser-welded joints of 6013-T4 aluminum alloy and DP980 steel were evaluated for their morphology, microhardness, and corrosion resistance. Corrosion resistance was assessed using the electrochemical noise technique over time in 0.1 M Na₂SO₄ and 3.5% NaCl solutions. The wavelet function was applied to remove the DC trend, and energy diagrams were generated to identify the type of corrosive process occurring on the electrodes. Corrosion on the electrodes was also monitored using photomicrographic images. Analysis revealed an aluminum–steel mixture in the melting zone, along with the presence of AlFe, AlFe₃, and AlI₃Fe₄ intermetallic compounds. The highest Vickers microhardness was observed in the heat-affected zone, adjacent to the melt zone, where a martensitic microstructure was identified. The 6013-T4 aluminum alloy demonstrated the highest corrosion resistance in both media. Conversely, the electrochemical noise resistance was similar for the DP980 steel and the weld bead, indicating that the laser welding process does not significantly impact this property. The energy diagrams showed that localized pitting corrosion was the predominant form of corrosion. However, generalized and mixed corrosion were also observed, which corroborated the macroscopic analysis of the electrodes.

This study investigates the mechanical behavior of water-washable photosensitive resins used in masked stereolithography (mSLA) 3D printing, evaluating the effect of post-curing time (0, 5, 10, 30, and 60 min) and printing orientation (Flat [XY], Vertical [Z], and On-edge [XZ]) on the material characteristics. Specimens were manufactured according to ISO 527-2 type 1B and ISO 178 standards for tensile and bending tests, respectively. A Matlab algorithm was developed to automate the processing of experimental data. This tool enabled the extraction of parameters to fit distinct mathematical models for the elastic (linear) and nonlinear (polynomial) regimes, allowing the material response to be characterized at different curing times and print orientations. These models were implemented in Ansys Workbench for comparison with experimental results. The results show that increasing the post-curing time from 0 to 60 min raises the elastic modulus from 964.5 to 1892.4 MPa in the Flat [XY] orientation and from 774 to 1661.2 MPa in the Vertical [Z] orientation for tensile testing. In bending testing, the Flat [XY] orientation presented the best mechanical properties, while the Vertical [Z] and On-edge [XZ] orientations showed similar behavior. The numerical simulations adequately reproduced the experimental results, validating the developed constitutive models. Finally, a stress–strain correlation model is presented that enables estimation for any post-curing time between 0 and 60 min. This study provides essential data for optimizing 3D printing processes and developing structural applications with photopolymer resins.

We show that low-frequency audible sound drives the crystallisation of distinct solid forms of organic compounds in solution crystallisation.

This exploratory pilot study introduces the Gluteus-Vastus Temporal Coordination Model (GVTCM), a methodological framework for assessing dynamic knee stability through phase-based neuromuscular analysis in elite footballers. Five professional male footballers performed single-leg vertical countermovement jumps. Surface electromyography of the gluteus medius (GM) and vastus medialis (VM) was analyzed within a 100 ms pre-activation window preceding initial contact (IC), operationalized as a binary feedforward variable. Dynamic Q-angle, Rate of Force Development (RFD), and Clarke's sign were assessed concurrently. Four athletes demonstrated anticipatory co-activation of GM and VM, presenting dynamic Q-angles of 11.8–13.1° and RFD of 4,200–4,800 N/s with negative Clarke's sign. One athlete, lacking feedforward activation in both muscles, exhibited a dynamic Q-angle of 18.5° and RFD of 7,200 N/s with positive Clarke's sign. A negative correlation between GM feedforward activation and RFD was observed (ρ = -0.67, 95% CI: -0.89 to -0.21). The convergence of biomechanical, kinetic, and clinical findings provides preliminary descriptive coherence to the GVTCM framework. These exploratory, hypothesis-generating findings suggest that anticipatory neuromuscular activation may be a clinically relevant indicator of dynamic knee stability and warrant validation in larger prospective cohorts.