Investigation of Porosity and Mechanical Properties of Graphene Nanoplatelets Reinforced AlSi10Mg by Selective Laser Melting

Abstract

Graphene possesses many outstanding properties, such as high strengths, light weight, making it an ideal reinforcement for metal matrix composite (MMCs). Meanwhile, fabricating MMCs through laser assisted additive manufacturing (LAAM) has attracted much attention in recent years due to the advantages of low waste, high precision, short production lead time, and high flexibility. In this study, graphene reinforced aluminum alloy AlSi10Mg is fabricated using selective laser melting. Composite powder is prepared using high-energy ball milling. Room temperature tensile tests are conducted to evaluate the tensile properties. Scanning electron microscopy (SEM) observations are conducted to investigate the microstructure and fracture surface of obtain composite. It is found that adding GNPs significantly increases porosity and therefore deteriorates material tensile performance. The relationship between porosity and material strength are numerically investigated. Taking into consideration the strength reduction caused by large porosity, the strengthening effect of GNPs turns out to be significant, which reaches 60.2 MPa.

Understanding powder degradation in metal additive manufacturing to allow the upcycling of recycled powders

“…Pores are regions where cracks initiate under stress (Wang et al, 2012;LPW Technology Ltd, 2018b), and it is well known that increased porosity leads to a decrease in material properties in various materials (Wang et al, 2017;Cherry et al 2015). Pores close to the surface of a specimen lead to stress concentrations which could lead to component failure (Seyda et al, 2012), whilst irregularly shaped pores with corners initiate microcracking, and thus failure, under loading (Pal et al, 2020).…”

Non-oxidized graphene/metal composites by laser deposition additive manufacturing

“…Generally, tensile strength and hardness of Al composites increase with the graphene content. SLM -one of 3D printing methods -[28,40,60] did not show significant improvements in tensile strength, hardness and elongation at break in comparison with…”

“…summarizes the mechanical performance of Al/graphene nanocomposites prepared by different methods[28,40,[60][61][62][63]. It is evident that method of fabrication is a key factor in determining mechanical properties of Al composites.…”