TITLE:
Property and Oxidation Behaviours of (Mo,Cr)Si2 + ZrO2 Composite Produced by Pressure-Less Sintering
AUTHORS:
Yiming Yao, Erik Ström, Xin-Hai Li, Qin Lu
KEYWORDS:
MoSi2, Composite, Fracture Toughness, Mechanical Property, Microstructure, High Temperature Oxidation
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.4 No.7,
July
25,
2016
ABSTRACT:
A composites of (Mo0.9Cr0.1)Si2 + 15vol% ZrO2 was prepared with powder metallurgy and Pressure- Less
Sintering (PLS) method, aiming at applications of high temperature structural
materials. Mechanical properties of the composites were assessed with hardness,
indentation fracture toughness Kc and KIC tested using
SEVNB, flexure strength at room temperature and 1200?C, and isothermal oxidation at 1400?C.
The results showed that the native silica oxide and molybdenum-oxides on the
silicide feedstock surface were significantly reduced in terms of Cr-alloying. (Mo0.9Cr0.1)Si2 and its composite also exhibited improved sinterability and grain growth, owing
to the presence of (Cr, Mo)5Si3 at grain boundaries.
Fracture toughness of the composite was increased by a factor of 1.6 to that in
the monolithic silicide. Mechanical property of the composite at high
temperature was not affected by Cr addition. However, the high temperature
oxidation resistance was greatly improved in the (Mo0.9Cr0.1)Si2 + 15vol% ZrO2 compared with the non Cr-alloyed counterpart. The
Cr-alloying effects on the microstructure, fracture behaviour, and high
temperature oxidation resistance were discussed.