Study of forming limit curves and mechanical properties of three-layered brass (CuZn10)/ low carbon steel (St14) /brass (CuZn10) composite considering the effect of annealing temperature

Abstract

In this study, the effect of annealing temperature on the mechanical properties and formability of brass (CuZn10)/low carbon steel (St14)/brass (CuZn10) composite sheets fabricated by the cold roll bonding (CRB) process were studied. The results showed that CRB process increases the tensile strength and hardness drastically while elongation decreases sharply. However, due to the recrystallization phenomenon, annealing operation can moderate the effect of these changes in mechanical properties. The most significant decline in ultimate tensile strength (UTS) and enhancement in elongation compared to the as-received sample were 90% and 295%, respectively. These results appeared at a temperature of 600 °C. Also, examination of the microstructure of the composite shows that at this temperature, full crystallization happens in the St14 steel layer that, as a result, new equiaxed free strain grains grow. The presence of dimples in the SEM images of the fracture surface indicates ductile fracture mechanism in all samples. The dimples become deep and equiaxial as the annealing temperature increases, indicating more ductility. In addition, after obtaining the forming limit diagram, it was found that annealing heat treatment improves the formability of CuZn10/St14/CuZn10 composite.

Keywords

• Roll bonding process
• Brass (CuZn10)/low carbon steel (St14)/brass (CuZn10) composite
• Mechanical properties
• Forming limit diagram
• Annealing temperature