Abstract: Aiming at intrinsic characteristics of sintering expansion for sintering billets, the process of powder compacting followed by vacuum hot pressed sintering and hot extrusion was put forward to densitify the composite powders. To provide higher relative density and high quality billets for subsequent sintering, the relation curves of pressed compacts prepared by high-energy mechanical milling 3%C-Cu (mass fraction) powders about relative density vs compacting pressure were achieved by means of one-direction pressing with rigid mould at room temperature. Cold compactability of these powders was investigated with HUANG Pei-yun’s log-log powder compacting theory. Microstructures and microzone composition of high-energy mechanical milling 3%C-Cu powders were analyzed with scanning electron microscope and field emission scanning electron microscope. The results show that when the high-energy mechanical milling time increases, the relative density of pressed compact decreases gradually under the same compacting pressure. The relative density of pressed compacts, which were prepared by high-energy milling 3%C-Cu powders with the same high-energy mechanical milling time, increases with increasing compacting pressure. It is more and more difficult for high-energy milling 3%C-Cu powders to be compacted when prolonging high-energy mechanical milling time. Pressed compacts with better quality can be obtained when compacting pressure and dwell time are 700 MPa and 30 s, respectively.

Key words: 3%C-Cu powder; high-energy mechanical milling; cold compactability; relative density