The present work concerns the influence of surface (machined, as-built) on the fatigue resistance of AlSi10Mg produced by a powder-bed laser process. The competition between defects and surface roughness is assessed by using Kitagawa-type diagrams. Samples are printed along three directions: 0°, 45° and 90°. After axial fatigue tests with a load ratio of R = −1, all the fracture surfaces are carefully analysed. The initiation sites can be (i) a defect, (ii) the surface roughness, (iii) the surface ripple. The results indicate that ground surfaces lead to the same fatigue life as as-built surfaces. It is also shown that T6 treatment improves the fatigue resistance. However, when specimen surfaces are as-built or ground, it is difficult to correlate the fatigue results with ‘isolated defect size analysis’ neither roughness parameter for an as-built surface. Therefore, microstructure, residual stresses or multiple initiation should be further analysed to understand the results.

Ti₃SiC₂ is a member of the family of layered ternary compounds well known as the M_n+1AX_n phases (n = 1 – 3, or ‘MAX phases’) where M is a transition‐metal, A is an A‐group element and X is either carbon or nitrogen. These compounds have attracted increasing attention since they possess a unique combination of metallic and ceramic properties. They are elastically stiff, electrically and thermally conductive, relatively soft, damage tolerant and resistant to thermal shock. Therefore, Ti₃SiC₂ have been proposed to be used in the generation IV nuclear reactors and several works were devoted to studying radiation damage by high energy heavy ions. Ti₃SiC₂ is mainly synthesised by powder metallurgy. Nevertheless, it was recently shown that monocrystalline Ti₃SiC₂ thin films onto 4H‐SiC can be formed by magnetron sputtering using Al and Ti co‐deposition on SiC at room temperature following by an annealing [1]. Ti₃SiC₂ formation is based on interdiffusion processes between the substrate and the deposited layer. A layered hexagonal structure is obtained which consists of alternate near‐close‐packed layers of Ti₆C octahedral interleafed with layers of Si atoms. Thin‐film of Ti₃SiC₂ could become suitable for many applications such as electrical contacts, wear protective coatings and to produce the new 2D materials labelled MXène. It is then crucial to progress in the knowledge of the physical properties of Ti₃SiC₂ thin‐film especially their behaviour under ion implantation. Light ion implantation (He, H) is commonly used to produce two dimensional defects in Si which are considered to be the precursors of cracks that are particularly interesting for the thin layer transfer technique well‐known as the smart‐cut process. The purpose of this work is to study the defects induced by light ion implantation (He, H) in Ti₃SiC₂ thin‐film in order to create He/H‐platelets. The microstructural analysis of the implant Ti₃SiC₂ thin films and their evolution under subsequent annealing will be performed by XRD and XTEM. First XTEM results (Fig. 1) show a high density of He‐platelets after low energy He implantation at medium fluence and subsequent annealing. Works are in progress for studying in more detailed the MAX phase and the He‐platelets. Results will be compared to a theoretical work who predicts that He atoms prefers staying near Si atoms [2]. The authors wish to acknowledge P. Guerin for his help during the film deposition and M. Marteau for He implantation experiments.