Brittleness of Cobalt-Iron Alloys

The brittleness of several cobalt‐iron alloys has been investigated. A theoretical evaluation of the hardening mechanism of isotropic short‐range order and long‐range order coupled with anisotropic short‐range order is made for the stoichiometric composition $\mathrm{CoFe}$ . The critical shearing stresses associated with the mechanisms are estimated together with that of interstitial atoms. In the absence of the effect of interstitials and other interferences, the hardening mechanisms of order may give rise to the brittleness of Co‐Fe alloys. Experiments on two Co‐Fe alloys with the addition of Cr or V establish the embrittling action of hydrogen at the grain boundaries.