PEST REACTIONS IN INTERMETALLIC COMPOUNDS Ⅱ Investigations on NiAL and Two MoSi2 Structures

摘要

The grain boundary hardening phenomena investigated earlier in the case of the intermetallic compound NiGa have been found to occur in much the same manner in NiAl. As before, an oxygen-contamination heat treatment followed by a sufficiently high temperature quench shows no hardening, but subsequent lower temperature aging sets up hardening. Hardening occurs in the bulk as well as along grain boundaries, but generally the effect is harder to observe in the former case because of shallow oxygen penetration in the bulk as compared to the grain boundaries. A vacancy-oxygen atom interaction model is suggested as a likely explanation for the observed hardening.