The room-temperature stress (σ) -strain (ϵ) curves of four materials P, Q, R, and S are shown in the figure below. The material that behaves as a rigid perfectly plastic material is
1
P
2
Q
3
R
4
S
The room-temperature stress (σ) -strain (ϵ) curves of four materials P, Q, R, and S are shown in the figure below. The material that behaves as a rigid perfectly plastic material is