Cold rolling of B2 intermetallics

Cold-rolling behavior was investigated for B2 intermetallics in terms of chemical compositions (constituent elements and ternary addition), long-range ordering and environments. B2 intermetallics used were NiTi, FeCo and FeAl alloys and cold-rolling behavior was evaluated through Vickers hardness tests at room temperature as a function of reduction of thickness. The effects of compositional deviation from the stoichiometry and Co addition were studied for B2-stabilized NiTi alloys. It was found that reduction to failure is lowered with increasing the compositional deviation from the stoichiometry, i.e. with decreasing Ti content, and Co addition raises both the reduction to failure and hardness. The effects of order–disorder transformation were studied for V-added FeCo alloys, and it was found that the reduction to failure is lowered and the work-hardening rate is raised by ordering. The effects of wet environment and ternary addition were studied for FeAl alloys with or without Mn or Cr. It was found that hardness-reduction relationship slightly depends on environment and ternary addition, and largely depends on Al content. However, formation of cracks and/or burrs is much affected by the environment and the ternary additions in a complex manner. It is summarized for B2 intermetallics that cold-rolling behavior is largely affected by chemical compositions of constituent phases and ordering, and slightly by the environment.