Y. Wu; M. Watroba; G. Cios; K. Hamulka; F.F. Klimashin; C. Tian; Y. Zhou; J. Michler; G. Wu; J.J. Schwiedrzik
SSRN (2025) 5271880
While liquid casting is one of the most practical methods for synthesizing aluminum (Al) based
composites, the coarse grains formed due to high processing temperature significantly compromises
both strength and plasticity. Here we present an extrusion-annealing method that enhances strength
and plasticity of cast Al composites reinforced with silicon carbide (SiC) nanowires. The significant
improvement in mechanical performance is attributed to two key mechanisms: the alignment of
nanowires and the formation of thermally stable fine Al grains, achieved through sequential dynamic
recrystallization (DRX) and static recrystallization (SRX). The DRX was achieved through
generating and pinning of dislocations by intragranular reinforcement, whilst the dynamic
equilibrium of Al grain size during SRX is caused by the thermal stability of the Al-SiC interface.
This optimized processing route yields composites exhibiting exceptional mechanical properties,
including compressive strength exceeding 1 GPa with 28% plasticity, and notably, stable yield
strength even after prolonged annealing at 550°C. Our study demonstrates a new method to produce
high performance Al-based composites through the rational use of nanoscale reinforcement.