Evaluation of bonding integrity of hybrid-built AlSi10Mg-aluminium alloys parts using the powder bed fusion process

Abstract

Recent advances in metal additive manufacturing (AM) technology enable complex conformal cooling channels to be fabricated for injection and blow mould inserts. However, high manufacturing costs hinder the technology being adopted in the mould-making industry. A cost-effective hybrid strategy was developed for the powder bed fusion (PBF) process in which powder materials get additively deposited onto pre-machined substrates as a practical cost-reduction solution. In this study, the interface bonding integrity, in terms of microstructure and mechanical properties, of powder AlSi10Mg and three types of substrate aluminium alloys were evaluated. Microstructure analysis revealed excellent powder-substrate fusion across the narrow interface of the three samples. All tensile specimens ruptured at least 5 mm away from the bonded interface, at the side where the material was of lower strength. Samples fabricated with AlSi10Mg-Alumec 89 alloys had the highest tensile strength of 481 MPa, about the same as standard as-built AlSi10Mg aluminium. Using the PBF-machined substrate hybrid AM strategy, Alumec 89, a high strength tooling-grade aluminium alloy, can be used as the base substrate for the fabrication of durable and high-performance aluminium injection and blow mould inserts.