A fine-grained fusion zone characterises a tough aluminium weld. To improve the solidification characteristics and refine the grains in aluminium welding, different inoculation particle combinations were introduced to the filler wire by solid state metal screw extrusion. Filler wires were I-joint welded with two different welding methods to reveal the potency for grain refinement. Grain size, microstructure, porosity content, and hardness across the weld was revealed. Gas metal arc welding with a Ti-TiC inoculated filler wire exhibited a remarkable grain refinement of 91% compared to a base reference of commercial pure aluminium. The Al $$_3$$3 Ti intermetallic phase was found as nucleation point. Gas tungsten arc welding showed lower grain refinement potency, and no Al $$_3$$3 Ti phase was found in any weld. Thus, the effect of welding method must be taken into consideration upon development of inoculant containing filler wires.

Metal screw extrusion (MSE) is a continuous, solid-state forming method utilizing an inherently high degree of deformation to consolidate fragmented input materials into a solid bulk by breaking their oxide skins. Severe plastic deformation with equivalent strain in the range of 10–20 can be achieved depending on set process parameters. Rigorous mixing can be employed to form sophisticated materials like bulk composites, nanocomposites, particle-reinforced metals, and fine-grained materials. Furthermore, the inherent solid-state processing is well suited for recovery of difficult-to-recycle materials. A range of non-ferrous materials has been manufactured by MSE and further characterized in terms of microstructural evolution and mechanical and functional properties. Furthermore, MSE has been studied in terms of flow, accumulated strain, and environmental impact. The following review aims to critically highlight the existing work performed on MSE, compare it to existing and emerging technologies as well as explore future development and possible applications. MSE has the potential to be utilized for numerous commercial applications. To realize industrial use of MSE, key aspects of the process and the influence of processing parameters on the resulting product must be understood.