Abstract: Theory research of MSP（Modified Small Punch）creep test was performed based on the thin plate bending creep model and the theory formula of creep stress exponent was established. A numerical study was carried out to simulate MSP creep tests by using the finite element software MARC. The creep stress exponent adopted in the numerical simulation was compared with the evaluation result. It is found that differences are 1.6% and 2.7% for 12Cr1MoV steel and tungsten-alloyed 9% Cr steel, respectively. The difference between the MSP creep test result of SUS304 stainless steel and the traditionally uniaxial creep test result is only 2.9%. The validity of the theory formula is verified by the consistency of numerical simulation results and by the excellent agreement with the experimental results. Based on the research of the creep properties of Si₃N₄ ceramic, it is found that there are both preferable ductibility and obvious creep deformation at 1000℃. The creep stress exponent of Si₃N₄ ceramic is obtained by using the theory formula. The results indicate that the MSP creep test method has wide application for the evaluation of high temperature creep properties of nonmetal materials.

Key words: MSP, Si₃N₄ ceramic, creep properties