Structures，properties and responses to heat treatment of
deformation processed Cu-15%Cr composite
powders prepared by mechanical milling
deformation processed Cu-15%Cr composite
powders prepared by mechanical milling
(School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China)
Harbin Institute of Technology, Harbin 150001, China)
Abstract: Cu-15%Cr composite powders were produced from elemental powders by mechanical milling technique. The structures, properties and thermal stability of the composite powders were characterized by scanning and transmission electron microscopy (SEM and TEM, respectively), electron probe microanalysis(EPMA), X-ray diffractometry and microhardness testing. The results show that powders are first flattened into thin discs at the initial stage of milling and then evolved into spheroid on further milling. Lamellar structure in powders is produced after intermediate milling. The Cr laminas degenerate into particles uniformizing in Cu matrix with excessive milling. The microhardness values and internal strain sharply increase with increasing milling time. Nano-sized Cu grains were found by TEM analysis. The microstructural observations suggested that the composite powders have high thermal stability and both spherodisation and thermal grooving contribute to the instability of Cr laminas.
Key words: Cu-Cr alloy; deformation processed composite; mechanical milling