This project examined how additive manufacturing parameters influence the microstructure and mechanical behaviour of biodegradable magnesium alloys, with the aim of advancing materials suitable for temporary biomedical implants. The magnesium alloy WE43 is especially promising because it is biocompatible and gradually dissolves in the body, removing the need for a second surgery to extract the implant. However, producing components with reliable and predictable mechanical properties remains challenging, particularly when using laser‑based additive manufacturing.
Powder bed fusion – laser beam (PBF‑LB) was the primary manufacturing method investigated to understand how process settings affect the final material. The study systematically varied laser power, hatch distance, build orientation, and scan rotation to assess their impact on grain structure, crystallographic texture, and mechanical performance. Neutron diffraction experiments were essential in this work, enabling the measurement of crystallographic texture and residual stresses deep within the printed components. Unlike many surface‑sensitive techniques, neutron methods allow researchers to probe the internal structure of bulk metal samples, making them especially useful for studying residual stresses and anisotropy in complex 3D‑printed materials.
The results showed that process parameters strongly influence both the microstructure and the mechanical anisotropy of additively manufactured WE43. Higher laser energy promoted the formation of equiaxed dendritic grains and improved tensile strength. Build orientation also had a significant effect on residual stress and mechanical behaviour: horizontally built samples demonstrated up to 40% higher tensile strength than vertically built ones, driven by the development of a strong basal texture. The study further demonstrated that laser scan rotation strategies can be used to purposefully modify crystallographic texture, offering new possibilities for microstructure control.
By connecting additive manufacturing parameters with internal microstructure and mechanical performance – and by using neutron diffraction to reveal these relationships – this research provides a valuable framework for optimizing biodegradable magnesium implants produced by additive manufacturing. The findings support the development of patient‑specific medical devices with predictable mechanical behaviour and controlled degradation, contributing to the next generation of advanced biomedical implant technologies.