PSI - Issue 79

Daniela Neves et al. / Procedia Structural Integrity 79 (2026) 266–274

267

Keywords: Defects, Mechanical Properties, Processing Parameters, Selective Laser Melting, Ti-6Al-4V

1. Introduction The Ti-6Al-4V alloy is widely used in the aerospace, biomedical, maritime and automotive industries because of its exceptional properties, which surpass those of many conventional engineering materials. This alloy offers a unique combination of high fatigue strength, good creep behaviour, and low density, making it particularly suitable for applications that demand optimal performance under extreme conditions (Alves et al., 2024; Leyens & Peters, 2003). In recent years, Additive Manufacturing (AM) has emerged as an innovative alternative to conventional manufacturing methods, mainly due to its vast potential for producing components with complex geometries, as well as its reduction in labour, energy, and material consumption (Tshephe et al., 2022). Among the existing AM variants, Selective Laser Melting (SLM), represented in Fig. 1, is particularly relevant in the AM of titanium and its alloys. During the production process, a high-intensity laser successively melts thin layers of a metal powder bed, enabling the gradual build-up of the component. To achieve the desired geometry, the laser selectively scans the powder bed, melting only the areas required to fuse with the previously solidified layers [28]. This technology is desirable to several sectors, including aerospace, aeronautics, automotive, and medical, due to its high precision. As a Near-Net-Shape process and given that unused metal powder can be recycled, SLM results in significantly lower raw material consumption than subtractive technologies (Childerhouse & Jackson, 2019). However, despite its clear advantages, the widespread adoption of this technology still faces significant challenges, particularly in terms of reliability and consistency.

Fig. 1 – Selective Laser Melting

The main objective of this work is to investigate the influence of different SLM processing parameters on the formation of intrinsic defects in Ti-6Al-4V. Additionally, the effect of these defects on the material's mechanical properties is evaluated by analysing three sets of specimens produced with similar parameter combinations but with different proportions of recycled powder.

Nomenclature E d

Energy density [J/m 3 ] Laser power [W] Laser scanning speed [m/s]

P v h e

Hatch spacing [m] Layer thickness[m]