Processing copper-intermetallic fibrous composites from copper and titanium powders
Renata Mola, Andrzej Dziadoń, Jarosław Mazurek
Quarterly No. 2, 2011 pages 125-129
DOI:
keywords: powder metallurgy, copper matrix composites, extrusion, compression test
abstract Copper-intermetallic fibrous composites were produced using the powder metallurgy method followed by extru-sion. The mixtures of Cu powder with 1 wt.% Ti; 2.5 wt.% Ti and 5 wt.% Ti powder were cold pressed and sintered at a temperature of 850oC. The sintered material was extruded using the KOBO method. During extrusion the hard particles containing copper- titanium intermetallic phases undergo a plastic deformation assuming a fibrous shape as the processed composite consists of a copper matrix reinforced with fibrous particles of copper-titanium intermetallic phases. Metallographic examinations of the composites revealed uniform distribution of the reinforcing particles in the copper matrix. SEM investigations and X-ray microprobe analysis showed that as a result of sintering intermetallic phases were synthesized at the Cu-Ti interface. The Ti-Cu reaction products were composed of intermetallic phases in the external zone (at the copper-titanium interface) and the core containing a solid solution of copper in titanium. The microhardness of the reinforcing particles was 760 HV0.65. The samples of the composites and sintered unreinforced copper were examined in a compression test, parallel and perpendicular to the extrusion direction. The yield strength value of the composites increases with an increase in the number of reinforcing particles in the copper matrix. Mechanic anisotropy was observed for the Cu-2.5wt.% Ti and Cu-5wt.% Ti composites: the yield strength was higher for the composites loaded parallel to the extrusion direction than for those loaded perpendicular. The yield strength of the Cu-2.5wt.% Ti and Cu-5wt.% Ti copper-intermetallic fibrous composites was several times higher than that of the unreinforced copper.