High Temperature Properties of the MoSi_2 and MoSi_2-SiC Nonocomposites

摘要

High temperature properties of the monolithic MoSi_2 and MoSi_2 composite reinforced by nano-SiC particles were studied. The materials were prepared via powder metallurgy using high temperature controlled reaction sintering (CRS).rnCreep testing in four-point bending and in compression was performed in order to determine high temperature properties of the experimental materials. Comparison of the materials showed that incorporating of nano SiC particles into the MoSi_2 matrix resulted in improvement of creep resistance for temperatures up to 1473 K for applied stress from 50 to 100 MPa. Creep stress exponent (n) of the composite, measured after compressive creep testing, was 1.27 (1273 K) and 3 (1473 K), respectively. Microstructure and its response to high temperature loading were investigated by TEM using the thin foil technique.rnBased on the presented parameters of creep kinetics and transmission electron microscope analyses probable mechanism of creep deformation was determined.