Development of unique cross-lamellar microstructure, resulting in the drastic increase in fracture toughness in Cr/Ir-codoped (Mo0.85Nb0.15)Si2 crystals. (1st April 2017) - Hagihara, Koji
Abstract: We first found a development of unique "cross-lamellar microstructure" in the (Mo0.85 Nb0.15 )Si2 C40/C11b two-phase crystals which is a promising ultrahigh-temperature structural material, via the codoping of Cr and Ir. In the cross-lamellar microstructure, rod-like C11b -phase grains that extend along a direction perpendicular to the lamellar interface develop in addition to fine lamellae. The fine lamellar microstructure increases in the frequency of delamination for crack-tip blunting, and in addition the rod-like C11b -phase grains enhances its effectiveness by inducing the shear-ligament-like toughening. As a result, the drastic increase in fracture toughness, which was never accomplished until now, could be first achieved. Graphical abstract: