Wire arc additive manufacturing (WAAM) excels in producing medium to large components with a high deposition rate. Process optimization is crucial for uniform, defect-free components. This research employs orthogonal experimental design and response surface methodology (RSM) to control TIG WAAM-ed 308L stainless steel components. Varied parameters, including tungsten electrode angle, welding current, and speed, target weld bead attributes. Analysis of variance (ANOVA) evaluates multi-processing parameter influence on weld bead formation. Comparison with experimental results confirms accurate modeling of the relationship between parameters and bead attributes. The study optimizes process parameters and swing to enhance dimensional accuracy in single-layer and multi-layer components, improving precision, quality, and accuracy in thin-walled structures.

Ti–Al bimetallic components present extensive application prospects and have attracted considerable attention owing to their low cost and light weight. In this study, Ti–Al bimetallic structures with one, two, and five Al layers were fabricated via wire and arc additive manufacturing by cold metal transfer welding. During the deposition process of the first Al layer, the matrix was TiAl, and a needle-shaped Ti₃Al was formed. Subsequently, from the second deposition layer of the Al alloy, however, TiAl₃ was formed, and it exhibited an exceptional morphology with two types of structures: coarse columnar grain structures with identical growth orientation, and long strip-like structures with a random distribution. The formation order of Ti–Al intermetallic compounds was TiAl₃, TiAl, and Ti₃Al.

The long, straight grain boundary of the high-entropy alloy (HEA) produced via laser melting deposition (LMD) is prone to cracking due to unidirectional scanning (single wall). To enhance the competitive growth of columnar grains and improve the overall performance of the alloy, a vertical cross scanning method was employed to fabricate FeCoCrNi HEA (bulk). The influence of grain orientation on the microstructure and mechanical properties of FeCoCrNi-LMD was systematically investigated. Microhardness tests and tensile tests were conducted to assess the mechanical property differences between the single-wall and bulk samples. This study shows that using a single scanning strategy results in monolayer wall grains sized at 129.40 μm, with a max texture strength of 21.29. Employing orthogonal scanning yields 61.15 μm block-like grains with a max texture strength of 11.12. Dislocation densities are 1.084 × 10¹² m⁻² and 1.156 × 10¹² m⁻², with average Schmid factors of 0.471 and 0.416. In comparison to the FeCoCrNi-LMD single wall, the bulk material produced through cross-layer orthogonal scanning exhibited reduced residual stress, weakened anisotropy, and improved mechanical properties. These findings are expected to enhance the potential applications of FeCoCrNi-LMD in various industries.

In the present study; an AlCoCrFeNi high-entropy alloy (HEA) component was produced by laser melting deposition (LMD) technique. Then; a heat-treatment process based on the detection results of Differential Scanning Calorimeter (DSC) was used. The effects of heat treatment on the phase transition; microstructure and mechanical properties of the AlCoCrFeNi component were systematically studied. The results showed that low-temperature heat treatment (600 °C) had little effect on the microstructure and mechanical properties of component. The 800 °C heat treatment precipitated σ and face-center cubic (FCC) phases near grain boundaries in the component. The high dislocation capacity of FCC phase and precipitation strengthening of σ phase improved the strength and plasticity of this component. However; hard and brittle σ phase was not conducive to uniform distribution of microhardness. High-temperature heat treatment (1000 °C) caused the σ phase to remelt and increased FCC phase content at grain boundaries; resulting in a significant increase in strength and plasticity. Although the microhardness of the AlCoCrFeNi component after this heat treatment was reduced; the good strength and plasticity will facilitate its application in the structural field.

In this study, the (FeMnCrNiCo + 20%TiC) laser cladding layer was re-treated through multiple-pass in-situ laser remelting. Optical microscopy, scanning electron microscopy, and X-ray diffraction were used to analyse the evolution of microstructures and phases before and after the in-situ laser remelting processes. The micro-hardness and wear resistance of the composite coatings were systematically investigated using micro-hardness and abrasion. Results show that in-situ laser remelting decreased the dilution rate. The thermal effect of laser melting and the Maragni action in the liquid coating metal enabled the large-sized and loosened ceramic particles to remelt into the cladding layers. As a result, the ceramic particles in the cladding layers after in-situ laser remelting were modified considerably in terms of their spherification rate, dimension uniformity, and particle distribution. The weak spots caused by stress on the surfaces of the cladding layers were reduced, and accordingly the wear resistances improved.