Interphase boundary structure on the board faces of proeutectoid α plates in a retained β matrix has been studied in a Ti-6.62at. %Cr alloy by means of conventional and high resolution transmission electron microscopy. Misfit compensating ledges with b = c/2α are observed on the broad faces of α plates. Growth ledges, irregular in path, spacing and alignment, are also observed. The apparent habit plane of the broad faces of α plates and the riser directions of the misfit compensating ledges, determined by trace analysis, imply the presence of the structural ledges predicted in the companion modeling study. High-resolution TEM observation has revealed that biatomic structural ledges with (1100)α//(211)β terraces do indeed exist on the broad faces of α plates, with exactly the characteristics predicted. This result provides the first experimental evidence for structural ledges in any b.c.c.:h.c.p. system.
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