Hot rolling effect on mechanical properties of copper alloys strengthened by dispersion and uniaxially hot pressed

Abstract

Copper powder of 140 μm mean size was mechanical alloyed with several compounds, 2 % B₄C, 2 % ZrC, 1 % CrB, 2 % Cr₃C₂, 1 and 2 vol. % ZrB₂ in a RETSCH PM high energy balls mill. The alloying process was carried out in stainless steel containers during 6 or 8 h of milling, under argon atmosphere, and the ball to powder charge ratio was 5:1. Instead of HIP processing, the alloyed powders were consolidated by uniaxial hot pressing at 650 °C for 2 h at a pressure of 90 MPa in argon atmosphere. Afterward the compact samples of 30 x 10 x 10 mm were hot rolled at 850 °C with area reduction from 10 to 40 %. If an homogeneous hot pressing process is obtained, the subsequent hot rolling can be avoided as only an annealing effect is produced, characterized by a small decrease in hardness and tensile strength with a small increase in ductility.