Ys. Chou et al., Mechanical and thermal properties of combustion-synthesized perovskites, La1-xSrxCr0.2Fe0.8O3, J MATER RES, 16(12), 2001, pp. 3545-3553
This paper examined the room-temperature thermal and mechanical properties
of a mixed conducting perovskite La1-xSrxCr0.2Fe0.80O3 (x = 0.2 to 0.8). Po
wders were made by the combustion-synthesis technique and sintered at 1250
degreesC in air. Sintered density, crystal phase, and grain size were chara
cterized. Linear thermal expansion in air was also tested. Young's and shea
r moduli, microhardness, indentation fracture toughness, and biaxial flexur
e strength were determined. It was found that the linear coefficient of the
rmal expansion increased with increasing Sr content, while elastic modulus
appeared to decrease with increasing Sr content. Young's modulus of 128 to
192 GPa and shear modulus of 51 to 74 GPa were measured. A biaxial flexure
strength of 243 MPa was measured for the lowest Sr content batches. Batches
with higher Sr concentrations (x = 0.6 to 0.8) showed extensive cracking.
Indentation toughness showed a decrease with increasing Sr content. In addi
tion, fractography was used to characterize the critical flaw and the fract
ure mode.