Correlation between Twinning and Surface Rumpling Phenomenon during Plastic Deformation of Austenitic Manganese Steel

In this paper، the correlation between the surface rumpling and cracking phenomena with twinning mechanism during plastic deformation of Hadfield steel has been investigated. The effect of stacking fault energy and the amount of strain are evaluated. The experimental samples with specific amounts of carbon، manganese and aluminum resulting in different stacking fault energies، were produced using investment casting process. The tensile tests were conducted at ambient temperature. The microscopic and macroscopic investigations were done using optical and scanning electron microscopes. The observations have shown that surface crinkling of austenitic manganese steels is related to twining mechanism during plastic deformation. This plastic deformation mechanism causes rotation and inhomogeneous deformation of the grains and therefore، surface grains with free surfaces were becoming more crinkled and cracked. It was observed that crinkling and cracking phenomena takes place more and coarser with an increase in the strain.