Abstract
Considering the process of Ar1 transformation in steel it is concluded that in an eutectoid or eutectic reaction the length of PS and SK on the eutectoid or eutectic line PSK in the phase diagram shown by atomic percentage has an important role in the process and that the “abnormal structure” appears in hyperalloys if PS<SK or vice versa. In this report (1) the above mentioned relations, which have been already confirmed in many alloys in author’s previous works, were also confirmed in alloys forming double equilibrium diagrams and (2) reference was made to the curious “abnormal structure” in Cu-Si alloys. In the “abnormal structure” in Cu-Si alloys primarily precipitated γ crystals are surrounded by a banded structure of α+κ, the so-called Widmanstätten α.
