Development of unique cross-lamellar microstructure, resulting in the drastic increase in fracture toughness in Cr/Ir-codoped (Mo0.85Nb0.15)Si-2 crystals

作者：Hagihara Koji^*; Ikenishi Takaaki; Nakano Takayoshi

来源：Scripta Materialia, 2017, 131: 19-23.

DOI：10.1016/j.scriptamat.2016.12.029

• Transition-metal suicides
• Lamella
• Fracture toughness
• Microstructure

We first found a development of unique "cross-lamellar microstructure" in the (Mo0,85Nb0,15)Si-2 C40/C11(b) 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 C11(b)-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 C11(b)-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.

• 出版日期2017-4-1