The effect of pressure on the structural behaviour of In alloys with Cd, Sn
and Pb has been studied with diamond anvil cells using synchrotron radiati
on. The face-centred cubic phase (fcc) of an In alloy with 6 at% Cd transfo
rms under pressure into a face-centred tetragonal In-type phase, fct, with
c/a > 1. The fcc phases of In alloys with 40 and 60 at% Pb transform under
pressure to fct with c/a < 1. For the ambient pressure fct phase (c/a < 1)
of an In alloy with 20 at% Sn the distortion increases with pressure. The s
tability of the tetragonal phases under pressure with respect to the cubic
structure is discussed in terms of Brillouin-zone-Fermi-sphere interaction.