In order to avoid cold welding, 1 wt.% stearic acid was
added as a surfactant; (2) The BPOp/Al composite powders were
cold pressed to a relative density of 60% and heated to 300 C holding
for 30 min and then pressed to 80% of the theoretical density,
which made the center of the composite billet isolated from air;
(3) The composite billet was sintered at 450 C for 30 min and then
pressed under 1 GPa for 5 min; and (4) Finally, the sintering composite
was subjected to forging and hot-rolling deformations.