High strength-tough and super-dispersed carbonized polymer dots reinforced copper composites fabricated by ultrasonic spray pyrolysis

Dense intragranular distribution of nanoscale reinforcements is highly desirable since the effectiveness in balancing the strength-ductility trade-off in metal matrix composites . Herein, the extremely fine-sized carbonized polymer dots (CPDs, ∼4.3 nm) was selected as a novel ex-situ reinforcement, ultrasonic spray pyrolysis was employed to maximize the elimination of CPDs agglomeration and achieved the uniform intragranular distribution. Micro-pillar compression was conducted to uncover the intrinsic relationship between interface features and mechanical performance. Results revealed that the CPDs/Cu composite exhibited significant work hardening and strain delocalization, which were attributed to the exceptional strain/shear accommodation capability of the amorphous interface layers (AIL). Furthermore, the formation and transmission of shear transformation zones (STZs) would blunt the stress concentration associated with the dislocation plugging and in turn homogenize the plastic flow of composites. Strikingly, CPDs/Cu composites possessed extraordinary comprehensive properties, demonstrated the ultimate tensile strength , thermal conductivity and electrical conductivity of 470 MPa, 390 W/m·K and 93.2 % IACS, respectively. This work underscores the importance of nano-particle spatial distribution and interface structure configurations in regulating Cu composite properties for structural-functional applications. • Ultrasonic spray pyrolysis strategy realizes the intragranular distribution of extremely fine-sized CPDs. • The interface characteristics and dislocation behavior related to AIL was investigated by micro-pillar compression tests. • Benefiting from the formation and transmission of STZs, the AIL-typed interfacepossessed higher strain accommodation ability. • The stronger strain accommodation behaviors of the AIL-typed interface has granted a better tensile of CPDs/Cu composites.