Effect of Scan Strategies and Use of Support Structures on Surface Quality and Hardness of L-PBF AlSi10Mg Parts.

Ronny M Gouveia,Eleonora Atzeni,Francisco J G Silva,Jorge Lino Alves,Dušan Sormaz,António Bastos Pereira

doi:10.3390/ma13102248

Abstract

Additive manufacturing allows for a great degree of design freedom and is rapidly becoming a mainstream manufacturing process. However, as in all manufacturing processes, it has its limitations and specificities. Equipping engineers with this knowledge allows for a higher degree of optimization, extracting the most out of this technology. Therefore, a specific part design was devised and created via L-PBF (Laser Powder Bed Fusion) using AlSi10Mg powder. Certain parameters were varied to identify the influence on material density, hardness, roughness, residual stress and microstructures. It was found that on heat treated parts laser pattern strategy is one of the most influential aspects, showing that chessboard and stripes 67° improved outcome; average Ra roughness varied between 8–12 µm, residual stress was higher on vertical surfaces than horizontal surfaces, with the combination of support structures and stripes 67° strategies generating the lowest residual stress (205 MPa on a lateral/vertical face), hardness was non-orientation dependent and larger on samples with chessboard fabrication strategies, while microstructures were composed of α–Al dendrites surrounded by Si particles. The distribution and grain size of the microstructure is dependent on location regarding melt pool and HAZ area. Furthermore, Al–Mg oxides were encountered on the surface, along with pores generating from lack of fusion.

Highlights

Additive Manufacturing (AM) is a recent manufacturing process that has created a disruption with traditional manufacturing methods commonly used up until a decade ago [1]
An interesting aspect that can be noted is that all samples weighted below the expected theoretical weight and the 99% relative density mark was not achieved, a mark that has been achieved in other studies [65,67]
15 μm, scanning of 650 mm/s andmm/s a chessboard pattern strategy improved outcomes thickness of 15 μ m,speeds scanning speeds of 650 and a chessboard patternexhibit strategy exhibit improved when compared to the remaining results

Summary

Introduction

Additive Manufacturing (AM) is a recent manufacturing process that has created a disruption with traditional manufacturing methods commonly used up until a decade ago [1] This technology started with the manufacture of prototypes (essentially using polymeric materials), but has quickly evolved into metals, allowing today the production of numerous components for very important sectors, such as the aeronautical industry [2], medical supplies [3] and consumer goods [4]. It is a technique capable of building parts through the successive deposition of relatively thin layers, in a very diverse range of polymeric, metallic alloys or even composite materials.

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Results

Conclusion