Unlike conventional materials removal methods, additive manufacturing (AM) is based on a novel materials incremental manufacturing philosophy. Additive manufacturing implies layer by layer shaping and consolidation of powder feedstock to arbitrary configurations, normally using a computer controlled laser. The current development focus of AM is to produce complex shaped functional metallic components, including metals, alloys and metal matrix composites (MMCs), to meet demanding requirements from aerospace, defence, automotive and biomedical industries. Laser sintering (LS), laser melting (LM) and laser metal deposition (LMD) are presently regarded as the three most versatile AM processes. Laser based AM processes generally have a complex non-equilibrium physical and chemical metallurgical nature, which is material and process dependent. The influence of material characteristics and processing conditions on metallurgical mechanisms and resultant microstructural and mechanical properties of AM proc...

Laser additive manufacturing of metallic components: materials, processes and mechanisms

A review on selective laser sintering/melting (SLS/SLM) of aluminium alloy powders: Processing, microstructure, and properties

Mechanically alloyed nanocomposites

Review on superior strength and enhanced ductility of metallic nanomaterials

https://www.tandfonline.com/doi/pdf/10.1088/1468-6996/16/3/033502

A review on powder-based additive manufacturing for tissue engineering: selective laser sintering and inkjet 3D printing

Exfoliation of graphite is a promising approach for large-scale production of graphene. Oxidation of graphite effectively facilitates the exfoliation process, yet necessitates several lengthy washing and reduction processes to convert the exfoliated graphite oxide (graphene oxide, GO) to reduced graphene oxide (RGO). Although filtration, centrifugation and dialysis have been frequently used in the washing stage, none of them is favorable for large-scale production. Here, we report the synthesis of RGO by sonication-assisted oxidation of graphite in a solution of potassium permanganate and concentrated sulfuric acid followed by reduction with ascorbic acid prior to any washing processes. GO loses its hydrophilicity during the reduction stage which facilitates the washing step and reduces the time required for production of RGO. Furthermore, simultaneous oxidation and exfoliation significantly enhance the yield of few-layer GO. We hope this one-pot and fully-scalable protocol paves the road toward out of lab applications of graphene.

/pdf/fast-and-fully-scalable-synthesis-of-reduced-graphene-oxide-p3awlb23lu.pdf

Fast and fully-scalable synthesis of reduced graphene oxide

Synthesis and mechanical properties of Al matrix composites reinforced with few-layer graphene and graphene oxide

7075-T6 aluminum alloy plates were prepared by friction stir welding (FSW) followed by age hardening. A novel solutionizing method, namely cyclic solution treatment (CST), comprising of a repeated heating between 400 and 480 °C for 0.25 h was employed. The microstructure of the joints was studied by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The effect of CST on mechanical properties was assessed by means of tensile test and microhardness measurement. A significant grain size refinement is taken place by FSW whilst the grain size is not considerably changed after CST. The results show that precipitate particles of the welding area before and after heat treatment are MgZn2 and MgAlCu/Al7Cu2Fe, respectively. CST improves tensile strength and elongation while homogenizes the hardness distribution of the FSWed joint. A noteworthy enhancement in the hardness (~45%) and tensile strength (~33%) of the FSWed sample is achieved after CST and aging at 130 °C for 24 h. The tensile fracture surface of the Al alloy joint demonstrates fine dimples after CST while less-developed dimples are detected after aging.

Effect of cyclic solution treatment on microstructure and mechanical properties of friction stir welded 7075 Al alloy

In the present work, the densification and microstructure of M2 high speed steel powder processed by direct laser sintering method was studied. Test specimens were produced using a 200 W continuous...

Densification and microstructural evaluation during laser sintering of M2 high speed steel powder

Graphene, a single-atom-thick sheet of sp2 hybridized carbon atoms densely packed within a hexagonal crystal lattice, owes a significant portion of its rapidly expanding usage in various fields of ...

H. Asgharzadeh

Papers

Fast and fully-scalable synthesis of reduced graphene oxide

Synthesis and mechanical properties of Al matrix composites reinforced with few-layer graphene and graphene oxide

Effect of cyclic solution treatment on microstructure and mechanical properties of friction stir welded 7075 Al alloy

Densification and microstructural evaluation during laser sintering of M2 high speed steel powder

Aluminum Matrix Composites Reinforced with Graphene: A Review on Production, Microstructure, and Properties