Fig. 5. (a): EDX linescan across the Γ- and Γ1-phase on a polished cross section of a sample annealed at 663 K for 16 h in pack cementation. The LY3039478 boundaries are indicated by vertical lines. (b): SEM-micrograph of the Γ- and Γ1-phase on a polished and etched cross section of the same sample.Figure optionsDownload full-size imageDownload high-quality image (264 K)Download as PowerPoint slide
The layer growth of the Γ- and δ-phases obtained by pack cementation is described by Eq. (2). The values of the growth constants K and n are listed in Table 2. The ζ-phase is not considered, because its layer thickness rather decreases with time. Both the δ- and Γ-phase reveal a deviation from the parabolic growth characteristic with n = 0.5. More specifically, the δ-phase exhibits values of n above 0.5 and the Γ-phase below 0.5. The growth of the total layer is mainly determined by the δ-phase, whose thickness exceeds by far the layer thickness of the Γ-phase. This is reflected in the corresponding growth-rate time constant n of the total layer, which is close to medusa of the δ-phase.