The consolidation of nano-sized composite materials presents a challenge using conventional hot pressing methods. Spark plasma sintering (SPS) technology has shown great promise in the successful sintering of nanoreinforced composite materials. This qualitative review seeks to impart knowledge gathered, and progress made over the years on the consolidation of nanocomposite materials using SPS technology. The review is aimed at introducing this technology to the South African science and engineering community. Emphasis is on improving the mechanical properties of structural ceramic nanocomposite materials, which over the years have shown great promise in a wide range of applications, including transport, energy, mining, and the environment. Although success has been achieved within the laboratory for research purposes, there are still great opportunities to commercialize the technology for the production of larger components with more complex shapes. ceramic nanocomposites, structural materials, spark plasma sintering, fracture toughness, ceramic matrix composites.

A primary challenge associated with TiAl alloys is their low ductility at room temperature. One approach to overcome this flaw is attaining ultrafine grains in the alloy’s final microstructure. The powder metallurgy (PM) processing route favours the synthesising of ultrafine grains in TiAl alloys. This paper features the mechanical alloying (MA) process and rapid consolidation through the spark plasma sintering (SPS) technique, which comprises the PM process. Furthermore, a second approach discussed covers microalloying TiAl alloys. An evaluation of the influence of high oxygen content is also presented, including the formation of α-Al2O3. A section of the review delves into the dynamic recrystallisation mechanisms involved in elevated temperature deformation of TiAl alloys. The final section highlights the efficacy of ternary element additions to TiAl alloys against oxidation.

The laser powder bed fusion (LPBF) is an additive manufacturing technology involving a gradual build-on of layers to form a complete component according to a computer-aided design. The LPBF process boasts of manufacturing value-added parts with higher accuracy and complex geometries for the transport, aviation, energy, and biomedical industries. TiAl-based alloys and high-entropy alloys (HEAs) are two materials envisaged as potential replacements of nickel-based superalloys for high temperature structural applications. The success of these materials hinge on optimization and implementation of tailored microstructures through controlled processing and appropriate alloy manipulations that can promote and stabilize new microstructures. Therefore, it is important to understand the LPBF technique, and its associated microstructure-mechanical property relationships. This paper discusses the metallurgical sintering processes of LPBF, the effects of process parameters on densification, microstructures, and mechanical properties of LPBFed TiAl-based alloys and HEAs. This paper also, presents updates and future studies recommendations on the LPBFed TiAl-based alloys and HEAs.

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