BPOp with a density of 8.201 g/cm3 [11] were synthesized using
solid phase synthesis method from high purity starting powders of
BaCO3 and PbO in oxygen atmosphere. The size of the BPOp after
ball milling is 2–3 lm. Pure aluminum powders with a diameter
of about 74 lm were purchased from Beijing Institute of Aeronautical
Materials, China. The novel BPOp/Al composite was fabricated
using the following process: (1) The BPOp and Al powder with a
volume ratio of 1:19 were ball milled with ball-to-powder ratio
of 4:1 in argon atmosphere for 12 h to fabricate BPOp/Al composite
powders. 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. To
compare with the composite, a pure aluminum sample was also
fabricated under identical conditions.