Sustainable development and genetic algorithm–driven optimization of novel quail bone–derived hydroxyapatite reinforced Mg–3Zn alloy composites for orthopedic applications

Magnesium-based composites are considered to be promising materials for biodegradable orthopedic applications because of their biocompatibility and low density, but their practical application is limited due to insufficient hardness and unstable mechanical performance resulting from incomplete densification. This research presents the development of a sustainable Mg–3Zn/2 wt.% hydroxyapatite (HA) composite reinforced with quail bone-derived HA through powder metallurgy. An integrated Taguchi–Genetic Algorithm (GA) framework was employed to optimize microhardness while simultaneously evaluating the compressive load-bearing response relevant to orthopedic applications. Taguchi analysis identified compaction pressure and sintering temperature as the dominant parameters governing hardness evolution. The GA optimization converged to an optimum located near the upper processing limits (490.26 MPa, 550°C, 119.99 min), yielding a maximum predicted microhardness of 74.77 HV, exceeding the best Taguchi experimental condition. Microstructural analysis indicated that the GA-optimized condition produced a finer grain structure and better interparticle bonding, while the densification was still comparable to the best experimental run. The GA-optimized composite had an ultimate compressive strength that was increased to 127.88 MPa, which is about 30% higher than pure Mg and close to the strength range of cortical bone. Overall, the study demonstrates that combining bio-waste-derived HA with hybrid statistical–evolutionary optimization enables a mechanically balanced and sustainable Mg composite suitable for biodegradable orthopedic load-bearing applications.