| Abstract Scope |
Two copper-modified steels were analysed for their phase composition and mechanical response under as-received (AR) and quenched and tempered (Q&T) conditions. Precipitates were examined using electron microscopy, and their mean radius, number density, and volume fraction were predicted through MatCalc simulation. The dominant influence of co-operative/short-range diffusion in HCu steel led to degenerate pearlite formation (71% vol. pct.), whereas LCu steel exhibited lesser pearlite formation (3% vol. pct.). 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. |