C11b/C40 Lamellar Structure in a Ta-added Molybdenum Disilicide

C11b/C40 fully lamellar microstructures, similar to the well-known TiAl/Ti3Al lamellae, were obtained in Ta- and Nb-added MoSi2 polycrystalline alloys in a previous work. In the present study, the crystallography of the lamellar structure is investigated in a MoSi2-15mol%TaSi2 pseudo-binary alloy after homogenized at 1400°C for 168h, in order to provide some useful parameters for microstructural control to improve mechanical properties. The orientation relationship between C11b and C40 phases and its three distinct variants were identified. Coherency of the lamellar interface is analyzed in comparison with the TiAl/Ti3Al lamellae. Approach to modify the C11b/C40 lamellar microstructure to increase its coherency is discussed based on the results obtained.