Mechanical properties of a new high-strength, healable aluminium alloy processed by laser powder bed fusion

Details

Supervisors

Simar, Aude

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

enLaser Powder Bed Fusion (L-PBF) is attracting increasing attention for the manufacturing of high-precision metallic components, particularly in fields such as aeronautics, where weight reduction directly translates into fuel savings and a reduced ecological footprint. Aluminium is a material of choice due to its high strength-to-weight ratio. However, conventional aluminium alloys used in L-PBF exhibit limited damage tolerance. One promising strategy to extend the service life of L-PBF-manufactured parts involves the use of healable aluminium alloys, which typically suffer from low mechanical strength. To address this limitation, this master’s thesis investigates the mechanical properties of a new high-strength, healable aluminium alloy, Almazium®, specifically developed for L-PBF manufacturing. The first objective was to validate L-PBF processing parameters for pre-alloyed Almazium® powder and assess the influence of powder reuse on part performance. Four sets of parameters were tested using both new and recycled powder. Mechanical properties were evaluated via micro-hardness measurements and tensile testing. The parameter set P60–v600–HS60 was identified as optimal, yielding a hardness of 147 HV and a yield strength of 370 MPa. Furthermore, recycled powder demonstrated comparable results, although with a reduction in ductility of 30% relative to the new powder. The second objective explored the effect of isochronal (1-hour) heat treatments. A peak hardness of 159 HV was achieved at 300°C, attributed to the precipitation of coherent Al3Zr particles. However, heat treatment alone was insufficient to activate the eutectic-based healing mechanism previously demonstrated in Almazium® under Hot Isostatic Pressing (HIP). These findings highlight the need to identify a compromise between thermal ageing for mechanical strengthening and high-temperature post-processing techniques, such as HIP, to achieve effective healing.