Insights on the electrical conductivity enhancement mechanisms of carbon polymer dots (CPDs) reinforced Cu composites

Carbon polymer dots (CPDs) has represented unique potential in reconciling the incompatible properties of strength and electrical conductivity (EC) in copper matrix composites, while the mechanisms underlying EC improvement remain to be fully elucidated. 0.2CPDs/Cu composites prepared by conventional powder metallurgy processes achieves excellent mechanical and electrical conductivity simultaneously. Compared to pure Cu, CPDs not only participated in the construction of a better electronic transport pathway, but accelerated the twinning forming behavior, leading to outstanding strength(similar to 423 MPa) and electrical conductivity(95%IACS). Here the conductive behavior of CPDs/Cu composites was revealed through characterizing the intrinsic electrical properties of CPDs and composites microstructure evolution. CPDs not only participated in the construction of a better electronic transport pathway, but accelerated the twinning forming behavior. Increased twinning domain leads to the remarkable amelioration of grain boundary resistance, meanwhile, the intragranular CPDs made a significant contribution on the enhanced mechanical strength via Orowan strengthening. This work makes up the lack of understanding on the mechanical and electrical enhancement mechanism in our prior research.