Manganese steel, more commonly referred to as Hadfield steel or Mangalloy, is an austenitic manganese steel that exhibits high toughness, strain hardening and wear resistance after work hardening. Due to these unique properties it is used extensively in the mining industry for hammer tips and rock crushers. A limitation of this use is when the wear rate is so high in comparison to the rate of work hardening that the alloy never reaches peak hardness. One proposed method to prevent this is to form carbides within the matrix of the steel. The benefit of this is potentially two fold: Firstly, hard carbides would typically increase the wear resistance of the alloy. Secondly, the thermally induced strain placed on the alloy matrix around the carbide has the potential to pre-work harden the steel.
The extent of plastic deformation of a Fe–12.1 wt.%Mn–1.2 wt.%C with 15 vol.% NbC is examined through the use of EBSD pole figure mapping, observing changes in the orientation of the lattice that is in contact with carbide. Samples are compared before and after cold rolling to observe any changes to the efficiency of plastic deformation. The extent of this plastic deformation is mapped out to determine if there is an increase in the percentage of plastic deformation within the matrix. Nano-indentation is performed to determine if the thermal stress is sufficient to harden the steel matrix around the carbides and if less cold working is required to achieve work hardening of the matrix.
The results reveal that the thermal stress applied to the matrix by the inclusion of carbides is enough to induce plastic deformation. While the extent of plastic deformation is limited to regions close to primary carbides, it has the potential to substantially increase the work hardening rate of the bulk alloy.