Effects of ferrite volume fraction on the tensile deformation characteristics of dual phase twinning induced plasticity steel

• The effect of ferrite volume fraction on tensile behavior of dual phase TWIP steel.
• The higher ferrite volume fraction, the higher yield and ultimate tensile strength.
• Fracture surface of dual phase TWIP steel specimens has been characterized.
• The formation of DO3 ordered phase inside the ferrite grains has been identified.
• Ferrite possesses relatively higher hardness which increases by its volume fraction.

The deformation characteristics of dual phase twinning-induced plasticity (TWIP) steel containing different ferrite volume fractions have been investigated through tensile testing method. The results show that the yield and ultimate tensile strengths are increased by ferrite volume fraction, while the ductility is marginally influenced. The former is attributed to the formation of DO3 ordered intermetallic compound inside the ferrite phase. Furthermore, the SEM examination of fracture surfaces reveals the pattern of brittle facets corresponding to the ferrite regions. These are surrounded by ductile dimples belonging to the austenite areas. Moreover, the signs of plane sliding in the austenite phase have been recognized, which demonstrates the domination of the ductile fracture in the austenite areas.