Additive manufacturing (AM) constitutes the new paradigm in materials processing and its use on metals and alloys opens new unforeseen possibilities, but is facing several challenges regarding the design of the microstructure, which is particularly awkward in the case of functional materials, like shape memory alloys (SMA), as they require a robust microstructure to withstand the constraints appearing during their shape change. In the present work, the attention is focused on the AM of the important Fe-Mn-Si-based SMA family, which is attracting a great technological interest in many industrial sectors. Initially, an overview on the design concepts of this SMA family is offered, with special emphasis to the problems arising during AM. Then, such concepts are considered in order to experimentally develop the AM production of the Fe-20Mn-6Si-9Cr-5Ni (wt%) SMA through laser powder bed fusion (LPBF). The complete methodology is approached, from the gas atomization of powders to the LPBF production and the final thermal treatments to functionalize the SMA. The microstructure is characterized by scanning and transmission electron microscopy after each step of the processing route. The reversibility of the ε martensitic transformation and its evolution on cycling are studied by internal friction and electron microscopy. An outstanding 14% of fully reversible thermal transformation of ε martensite is obtained. The present results show that, in spite of the still remaining challenges, AM by LPBF offers a good approach to produce this family of Fe-Mn-Si-based SMA, opening new opportunities for its applications.

Fatigue properties of parts are of particular concern for safety-critical structures. It is well-known that discontinuities in shape or non-uniformities in materials are frequently a potential nucleus of fatigue failure. This is especially crucial for the Ti6Al4V alloy, which presents high susceptibility to the notch effect. This study investigates how post-processing treatments affect the mechanical performance of Ti6Al4V samples manufactured by laser powder bed fusion technology. All the fatigue samples were subjected to a HIP cycle and post-processed by machining and using combinations of alternative mechanical and electrochemical surface treatments. The relationship between surface properties such as roughness, topography and residual stresses with fatigue performance was assessed. Compressive residual stresses were introduced in all surface-treated samples, and after tribofinishing, roughness was reduced to 0.31 ± 0.10 µm, which was found to be the most critical factor. Fractures occurred on the surface as HIP removed critical internal defects. The irregularities found in the form of cavities or pits were stress concentrators that initiated cracks. It was concluded that machined surfaces presented a fatigue behavior comparable to wrought material, offering a fatigue limit superior to 450 MPa. Additionally, alternative surface treatments showed a fatigue behavior equivalent to the casting material.

The use of aluminum alloys in aerospace is limited by their poor weldability, making many incompatible with additive manufacturing (AM) processes like powder bed fusion—laser beam metal (PBF-LB/M), known as well as laser powder bed fusion. This incompatibility hinders the fabrication of complex, lightweight components. To overcome this, Aluminum Metal Matrix Composites (AMMCs) are formed by mechanically alloying the non-processable Al6082 base alloy with ceramic reinforcements; subsequently, Titanium Carbide (TiC) and Silicon Carbide (SiC) particles are developed. This approach induces microstructural changes necessary for AM compatibility. The influence of varying reinforcement contents (1–5 wt.%) on powder homogeneity, microstructural evolution (via Energy Dispersive X-ray Spectroscopy and Electron Backscatter Diffraction), processability, and mechanical properties is systematically studied. The key finding is that metallurgical modification is a robust solution. TiC addition at 2 wt.% and 5 wt.% completely eliminated solidification cracking, achieving high processability. SiC substantially reduced cracking compared to the base alloy. These results demonstrate the potential of AMMCs to successfully translate conventional, non-weldable aluminum alloys into the realm of advanced additive manufacturing.

Additively manufactured heat exchanger cores offer enhanced compactness, thermomechanical robustness, and improved integration within confined assembly spaces. However, their complex thin-walled lattice structures pose significant challenges for mechanical characterization and conventional finite element analysis, due to high computational costs. This study investigates the tensile mechanical properties of grid-like structures produced by powder bed fusion with a laser beam in aluminum alloy AlSi7Mg0.6 and nickel–chromium-based superalloy Inconel 718 (IN718). Samples with varying wall thicknesses were fabricated, heat treated, and some were surface treated to reduce surface roughness. Tensile tests combined with digital image correlation and non-linear finite element modeling were conducted to evaluate mechanical behavior. Experimental results reveal that a minimum solid material proportion (P _s ≈ 0.09 for AlSi7Mg0.6; P _s ≈ 0.06 for IN718) is required to achieve reliable elastoplastic deformation; below these thresholds, premature brittle failure dominates. Equivalent Young’s moduli and yield strength scale linearly with solid material proportion, the latter reaching approximately 59% and 52% of bulk material values for AlSi7Mg0.6 and IN718, respectively. Surface treatment contributed mainly to wall thickness reduction without significantly altering mechanical performance. Homogenized porous material models based on the Gibson–Ashby framework and a modified Hockett–Sherby constitutive law were developed, enabling efficient and realistic simulation of these complex structures. These findings provide critical experimental data and modeling tools essential for the design and optimization of next-generation additively manufactured heat exchangers in both alloys.