الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The average grain size of a material affects the mechanical properties. Nowadays, severe plastic deformation, especially parallel tubular channel angular pressing (PTCAP) is a grain refinement technique. Besides, copper and copper alloys are the most popular materials for PTCAP process. However, few researches on PTCAP processing of such alloys are available. Commercially pure Cu (99.95%), and brass (Cu-30%Zn) alloy are PTCAP processed up to 4 passes at RT following route ”A”. A die channel angle of φ1= φ2=135o , angle of curvature ψ1= ψ2=0o and imposed strain of ~2.5 per pass. Chemical analysis using Optical emission spectrometer (OES) of the pure Cu, and brass alloy are performed to confirm the alloy composition. The microstructure is studied before and after PTCAP processing using Optical Microscope (OM) and Scanning Electronic Microscopy (SEM). Also, tensile properties, hardness and wear resistance tests are measured. The microstructure evalutions indicated the grain refinement of the pure Cu, and brass with increase of the number of passes. The obtained fine grained microstructure with an average grain size of about ~2.2μm (after four passes). It is found that a microstructure in the as deformed condition exhibits an inhomogeneous distribution of grain size for pure Cu. For brass alloy the microstructural investigations show a notable decrease in the grain size with increasing the number of PTCAP passes. Also, the ultimate tensile strength (UTS), 0.2% proof strength and hardness of commercially pure Cu, and brass alloy with increase number of passes, due to the grain refinement and the work hardening during the PTCAP. However, UTS, 0.2% proof strength and hardness of pure Cu tube reach maximum values 67%, 187%, and 112%, respectively after 4 passes. Tubes of brass alloy reached maximum values (135%, 270%, and 189%)V respectively, after 2 passes. Besides, elongation percent of commercially pure Cu, and brass alloy decreased strongly from (24.85%, and 41.96) to (4.48%, and 5.95%) after 4 and 2 passes, respectively. Wear resistance of commercially pure Cu, and brass alloy is improved by increasing number of passes, especially after the first pass.