Gm. Janowski et Bj. Pletka, THE EFFECT OF PARTICLE-SIZE AND VOLUME FRACTION ON THE AGING BEHAVIOROF A LIQUID-PHASE SINTERED SIC ALUMINUM COMPOSITE/, Metallurgical and materials transactions. A, Physical metallurgy andmaterials science, 26(11), 1995, pp. 3027-3035
The aging response of a SiC particulate reinforced powder metallurgy a
luminum composite was examined as a function of particle size and volu
me fraction. The addition of SiC particles ranging in size from 24 to
142 mu m at 9 vol pet had no effect on the aging kinetics of the compo
sites. Acceleration of the aging behavior or inhibition of the initial
stage of the age-hardening process was observed at 18 and 27 vol pet.
The accelerated aging kinetics were consistent with smaller particles
creating larger thermal misfit dislocation densities. In addition, it
was shown that different combinations of ceramic particle size and vo
lume fraction lead to similar effects on the aging behavior. Loss of t
he initial hardening response was attributed to the suppression of Gui
nier-Preston (GP) zone formation due to the annihilation of excess vac
ancies at the thermal misfit dislocations.