Influence of Shot Peening on AlSi10Mg Parts Fabricated by Additive Manufacturing

Ahmed Maamoun,Mohamed Elbestawi,Stephen Veldhuis

doi:10.3390/jmmp2030040

Ahmed Maamoun, Mohamed Elbestawi + Show 1 more

Open Access

https://doi.org/10.3390/jmmp2030040

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Abstract

The additive manufacturing (AM) of aluminum alloys promises to considerably enhance the performance of lightweight critical parts in various industrial applications. AlSi10Mg is one of the compatible Al alloys used in the selective laser melting of lightweight components. However, the surface defects obtained from the as-built parts affect their mechanical properties, and thus represent an obstacle to using them as final products. This study aims to improve the surface characteristics of the as-built AlSi10Mg parts using shot peening (SP). To achieve this goal, different SP intensities were applied to various surface textures of the as-built samples. The SP results showed a significant improvement in the as-built surface topography and a higher value of effective depth using 22.9 A intensity and Gp165 glass beads. The area near the shot-peened surface showed a significant microstructure refinement to a specific depth due to the dynamic precipitation of nanoscale Si particles. Surface hardening was also detected and high compressive residual stresses were generated due to severe plastic deformation. The surface characteristics obtained after SP could result in a significant improvement in the mechanical properties and fatigue strength, and thus promise performance enhancement for critical parts in various industrial applications.

Highlights

Additive manufacturing (AM) produces a significant improvement in parts’ performance by achieving design flexibility and weight reduction
These particles keep the original microstructure of powder, and they do not have the same microstructure as the as-built part [23]
It is the high cooling rate applied to the final layer that makes the texture of these tracks appear; the width of the tracks is slightly larger than the laser beam diameter (100 μm)

Summary

Introduction

Additive manufacturing (AM) produces a significant improvement in parts’ performance by achieving design flexibility and weight reduction. AlSi10Mg is one of the most frequently used Al alloys for SLM due to its lower coefficient of thermal expansion (CTE), as compared to that of Al6061, which is commonly used in conventional techniques. The relatively low CTE of AlSi10Mg results in higher dimensional accuracy, superior mechanical properties, and the elimination of crack formation [1]. The as-built parts produced could have surface and microstructure defects. This represents an obstacle to achieving high surface quality and consistent mechanical properties. Surface defects, such as porosity and balling formation, considerably affect a part’s quality [2]. Spherical balls may form on the part surface due to the failure of wetting the underlying substrate by the molten material [3]

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