The effect of shock waves and strain hardening of laser shock peening without protective coating (LSPwC) on alloy AA 6082-T651 was investigated. Analysis of residual stresses confirmed high compression in the near surface layer due to the ultrahigh plastic strains and strain rates induced by multiple laser shock waves. Corrosion tests in a chloride environment were carried out to determine resistance to localised attack, which was also verified on SEM/EDS. OCP transients confirmed an improved condition, that is, a more positive and stable potential after LSPwC treatment. Moreover, polarisation resistance of the LSPwC treated specimen was by a factor of 25 higher compared to the untreated specimen. Analysis of voltammograms confirmed an improved enhanced region of passivity and significantly smaller anodic current density of the LSPwC specimen compared to the untreated one. Through SEM, reduction of pitting attack at the LSPwC specimen surface was confirmed, despite its increased roughness.

Friction riveting represents a promising technology for joining similar and/or dissimilar materials of light-weight components. However, the main drawback of the technology is that it is primarily used only with special machines for friction welding that have a force control. In this study we used accessible CNC machines with a position control. A set of friction riveting experiments was performed to establish the relationship between the processing parameters, the rivet formation and its mechanical strength. During the manufacturing process, the axial force and torque were constantly measured. The fabricated joints were examined using an X-ray imaging technique, microstructural analyses, and mechanical tests. The samples were subjected to the pull-out test to analyse the joints’ strength and determine the failure mode type. In addition, a correlation between the friction riveting processing parameters, the rivet penetration depth, the rivet shape and the joint strength was established. The results depict that a higher axial force in the first production phase at the higher feeding rate increases the penetration depth, while in the second phase at lower feeding rate, an anchoring shape of a rivet forms.

The study presents the results of remote robotic laser welding of advanced high strength Docol^® 1200 M martensitic steel. One mm thick samples were welded in a lap joint configuration using a special clamping system. Welding was done using a continuous-wave (CW) fibre laser with a constant welding power of 300 W and constant focus diameter Ø 1.8 mm. Welding was done using 12 different welding speeds in the range from 0.15 to 1 m/min, whereas the inclination angle was kept constant at 0°. The influence of various welding speeds and linear heat inputs during welding on microstructural changes were examined by the occurrence of acicular and allotriomorphic ferrite or martensite. Results revealed big influence of the clamping system on the accumulation of the laser beam energy, heat sink and consequently weld size and geometry, as well as its microstructure and joint strength. Tensile-shear strength, microstructure and hardness results confirmed laser power of 300 W and 0.6 m/min welding speed as the optimal parameters, at which a martensitic structure was obtained in the weld. The width of the heat affected zone (HAZ) in this case is 1100 μm.

This paper discusses directed energy deposition of 15-5 PH, which was successfully tailored with precipitation hardening (PH) to achieve the desired properties. Parametric analysis of solution annealing and aging at various time and temperature combinations was performed. Material characterisation was done in the as-deposited, solution annealed, and PH states. Investigations included microscopy, SEM/EDS, fractography, hardness, tensile, and impact toughness test. The as-deposited microstructure was composed of martensite laths along with delta ferrite. Optimisation of solution annealing was mandatory to achieve homogeneous austenite, which allowed PH. PH resulted in similar properties compared to conventionally produced steel. Peak aging resulted in 450 HV10 and an Rm of 1350 MPa, while the over-aged condition resulted in an impact toughness of over 77 J/cm².