Abstract
The optimisation of processing parameters to produce high densification AlSi10Mg parts by laser powder bed fusion (LPBF) has received considerable attention in recent years. Nonetheless, it is important to consider the potential presence of as-built large pores in real world applications, e.g. due to limitations of the available LPBF system, time and cost constraints associated with producing near-perfect density and so on. In this work, recycled powder was used to fabricate AlSi10Mg specimens with sub-optimal densification by LPBF and an experimental investigation into the evolution of specimen porosity occurring under increasing tensile load was performed. A combination of high-resolution X-ray micro computed tomography (XμCT) and an in-situ micro-testing stage was employed to acquire 3D images at different loading stages. Specimens were tested in the as-built condition and following hot isostatic pressing (HIPping) or HIPping with T6. As-built porosity did not change markedly in the lead-up to brittle-like fracture. Pores within ductile HIPped specimens were uniformly elongated up to the onset of damage propagation and pore coalescence. Pore shape change occurred largely without volume change at small extension. HIPping plus T6 produced a compromise between as-built and HIPped conditions in terms of the extent of pore modification observed prior to failure.
Highlights
Laser powder bed fusion (LPBF), broadly referred to as ‘selective laser melting (SLM)’, is a popular metal powder additive manufacturing [1,2].With very high strength-to-weight ratio, corrosion resistance and thermal conductivity, heat treatable Al\\Si alloys are widely used in aerospace and automotive applications
The evolution of internal porosity was analysed by in-situ tensile testing with incremental XμCT scanning at increasing extension
Large pores that remained open were elongated in the loading direction and transversely flattened before void growth development, with shape change occurring largely without volume variation at small extension
Summary
Laser powder bed fusion (LPBF), broadly referred to as ‘selective laser melting (SLM)’, is a popular metal powder additive manufacturing (each requiring requisite material consumptions, energies and costs) [1,2].With very high strength-to-weight ratio, corrosion resistance and thermal conductivity, heat treatable Al\\Si alloys are widely used in aerospace and automotive applications. Laser powder bed fusion (LPBF), broadly referred to as ‘selective laser melting (SLM)’, is a popular metal powder additive manufacturing (each requiring requisite material consumptions, energies and costs) [1,2]. The Al\\Si alloys can be strengthened, without changing other mechanical properties, by adding Mg due to the precipitation of Mg2Si. AlSi10Mg is one of the most commonly used Al\\Si alloys, traditionally manufactured by die casting. Casting requires part-specific tooling with cost and lead time implications. This process results in large grains with poor mechanical response (in view of the Hall-Petch relationship) as a result of low cooling rates [3]. Manufacturers are constantly striving to develop new cost-effective techniques to produce parts with enhanced accuracy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
