Creep deformation of single crystals of binary and some ternary MoSi2 with the C11b structure

The creep deformation behavior of binary and some ternary MoSi2 single crystals with the soft [0 15 1] and hard [001] orientations has been investigated in the temperature range from 1200 to 1400°C in compression. The alloying elements studied include Nb and Al that form a C40 disilicide with Si and W and Re that form a C11b disilicide with Si. The creep strain rate for the [001] orientation is significantly (2 orders of magnitude) lower than that for the soft [0 15 1] orientation. The creep strain rate for the [0 15 1] orientation is improved by an order magnitude upon alloying with Re and Nb while alloying with W and Al causes a decline in the creep properties of this orientation. The creep strain rate for the [001] orientation is further improved upon alloying with Re, Nb, W and Al with the extent of improvement significantly larger for the Re addition.