Microstructural development of as-cast AM50 during Constrained Friction Processing: Grain refinement and influence of process parameters

Mg and its alloys have a wide range of structural applications despite the limitations regarding the workability and low ductility associated with its hexagonal closed-packed structure. The Constrained Friction Processing (CFP) is a novel processing technique, developed based on the Refill Friction Stir Spot Welding process, that has been proposed as an interesting alternative that can help to overcome challenges associated with the processing of Mg and its alloys. This technique is shown to be able to produce homogenous fine-grained rods. Correlation between processing conditions and the evolved microstructure, i.e. texture and grain size, were established for AM50 rods. In the center, the produced rods present a strong B-fiber texture. As the distance from the center changes along the radial direction, there is a progressive outward tilt of the 0001 because of specific flow conditions during the processing. CFP is shown to be able to produce fine-grained rods with grain sizes comparable with other severe plastic deformation techniques, with advantages like no requirement of additional preheating and short processing times.

Automated summary

Despite the limitations of workability and low ductility, Mg and its alloys are widely used in structural applications. Constrained Friction Processing (CFP), a novel processing technique based on Refill Friction Stir Spot Welding, is proposed as an alternative to overcome the challenges in processing Mg and its alloys. CFP has shown the ability to produce fine-grained rods with a homogeneous microstructure and advantages such as no need for additional preheating and shorter processing times.