The
present work aims to assess the age hardening of microalloyed
Mg–Zn–Mn alloy reinforced with Ca10(PO4)6(OH)2 (hydroxyapatite, HAp) particles
to impart mechanical strength without deteriorating their degradation
and biocompatibility behavior for their suitability toward resorbable
fixation devices. The hydroxyapatite powder was synthesized with high
purity. Mg–Zn–Mn (ZM31) and Mg–Zn–Mn/HAp
(ZM31/HAp) were stir-cast, homogenized, and solution-treated to achieve
uniform dissolution. Further, they were given a range of aging treatments
(175 °C for 0, 5, 10, 25, 50, and 100 h), and the age hardening
was measured as Vickers microhardness. The solution-treated and peak-aged
(175 °C × 50 h) samples were further investigated using
optical and electron microscopy, tensile testing, electrochemical
corrosion testing, dynamic mechanical analysis, and biocompatibility.
The peak-aged ZM31 sample revealed the highest ultimate strength (134.09
± 5.46 MPa). The aging treatment resulted in notable improvement
in ductility in ZM31 (8.72 ± 1.38%) and yield strength in ZM31/HAp
(82.50 ± 1.43 MPa). The rapid strain-hardening behavior was distinctly
visible in peak-aged samples in the initial stage of deformation.
The amplitude-dependent internal friction confirmed the active solute
and age-hardening mechanisms in agreement with the Granato–Lücke
model. All samples displayed favorable cell viability (>80%) and
cell
adhesion behavior; however, their hemocompatibility and biodegradation
need further consideration.