| Abstract Scope |
Two copper-infused steels were studied for their phase composition and mechanical performance after quenching and tempering (Q&T). Precipitates were examined using electron microscopy (HR-TEM), and their mean radius, number density, and volume fraction were predicted through MatCalc simulation. In HCu steel, the primary influence of cooperative/short-range diffusion resulted in the formation of degenerate pearlite, while LCu steel showed reduced pearlite formation. The softening and hardening mechanisms during tempering was discussed, correlating with the transition of Cu precipitates from coherent BCC to incoherent FCC via semi-coherent 9R-crystal structures. HCu samples displayed higher yield strength (YS) and ultimate tensile strength (UTS). Following a 0.75-hour tempering, LCu steel exhibited strength (811 MPa), ductility (19.35%), hardness (267±4 HV), and a tensile toughness of 146*105 KJ/m3. The investigation established a comprehensive correlation between microstructure and mechanical properties through fractographic analysis and the coherency of different precipitates. |