The effect of microgravity on liquid phase sintering (LPS) in the Fe-C
u system was investigated through experiments on four sounding rockets
and on three Space Shuttle missions. Three compositions, namely, Fe-3
3 wt.%Cu, Fe-43 wt.%Cu and Fe-53 wt.%Cu were processed for times rangi
ng from 2.5 minutes to 66 minutes. The samples did not exhibit slumpin
g or shape distortion during processing. However, extensive pore forma
tion and metamorphosis was observed in all these samples, Microstructu
ral characteristics such as densification, dihedral angle, contacts pe
r grain, grain growth and pore metamorphosis were evaluated. The evolu
tion of LPS microstructure in microgravity is explained using energy c
onsiderations because the liquid, solid and gaseous phases in the Fe-C
u samples seek to attain the minimum energy configuration in the absen
ce of gravitational forces. Therefore, the volume fractions of liquid
solid and gaseous phases and processing times significantly influence
the LPS microstructure in microgravity. This paper documents the effec
t of composition and processing time on microstructural development in
the Fe-Cu samples that have been liquid phase sintered under microgra
vity.