Impression creep of MoSi2

The creep behaviour of a monolithic molybdenum disilicide has been investigated within a temperature range from 1100 degrees C to 1250 degrees C at applied stresses from 20 MPa to 100 MPa in air using the impression test method. The strain-time relationships have been recorded, and the creep exponents as well as the activation energies of creep have been calculated. The results are compared to the creep results of the same material tested in four-point bending mode. The stress exponent in impression was found to be approximately 1, and the apparent activation energy approximately 250 kJ mol(-1). In lower stress-temperature range the creep behaviour of MoSi2 in impression and bending mode is very similar, however at higher stress-temperature range the creep rate, stress exponent and activation energy are significantly lower in impression.