Effect of strain path change on mechanical properties and final microstructure of Cu–Al₂O₃ in equal channel angular pressing

Abstract

In the present work, the process of equal channel angular pressing of dispersion strengthened Cu-1?1 wt-%Al 2 O 3 containing nanometric alumina particles was investigated by means of mathematical modelling and experimental testing. Through the modelling, deformation parameters such as hydrostatic pressure distribution and strain field were determined, and the effect of deformation path on these parameters was estimated. Equal channel angular pressing as well as mechanical and microstructural evaluations were also conducted to assess mechanical properties, grain structure and void volume fraction after deformation in different routes. The results indicate that distributions of plastic strain and hydrostatic stresses are significantly affected by deformation path route as well as utilised die design. Furthermore, void formation around hard alumina particles may occur in regions with high tensile hydrostatic stresses leading to fracturing during deformation.

Softening behaviour of alumina reinforced copper processed by equal channel angular pressing

“…This could be attributed to the void formation around hard alumina particles due to development of tensile hydrostatic stresses during plastic deformation. 12 This observation is also in agreement with that observed by Fathy et al, 13 where all tested Cu-Al 2 O 3 specimens were cracked before reaching 50% reduction in height during compression tests. The PEEQ contours throughout the longitudinal and transverse cross-sections of deformed alloy are also observed in Fig.…”

“…The alloy was fabricated by internal oxidation method employing the procedure explained in the previous work. 12 The as received rod with a diameter of 18 mm was first annealed at 1000uC for 60 min to remove the effect of previous cold working, and then, it machined into the rods with 14 mm in diameter and 100 mm in length for ECAP experiments. A hydraulic press of 60 ton capacity was utilised to deform the billets via single pass ECAP at ambient temperature with a pressing speed of 1 mm s 21 .…”

Fabrication and characterisation of copper–alumina nanocomposites prepared by high-energy fast milling

“…6–8 These characteristics imply that the metal–matrix composites (MMCs) of Cu–Al 2 O 3 are characterised by two crucial factors: high strength with high-temperature hardness, and high thermal and electrical conductivities. 9–11 Therefore, Cu–Al 2 O 3 is potential candidates in cases where high strength and high electrical conductivity are required. Cu–Al 2 O 3 can be applied in aerotechnology, 12 electronic packaging 13 and electrodes.…”