Ultrastrong pure iron wires have been produced with a strength of 1.8 GPa with a strain of 10.35. Based on microstructural observation and quantified structural parameters, the strengthening mechanisms and strength-structure relationship have been analyzed. It is found that the <110> fiber texture intensity, boundary spacing and boundary misorientation tend to saturation due to the boundary junction motion when the drawing strain exceeds 8.89. The dislocation density in the ferrite cells/lamellae increases to ~ 3.6 × 1015 m−2 at a drawing strain of 10.35 without saturation. Based on the systematic microstructural characterization and quantification, the d−1 or (2d)−0.5 boundary strengthening plus forest hardening are discussed.
- Cold drawing
- Pure iron wires
- Strength-structure relationship
- Strengthening mechanisms