DEVELOPMENT OF CRYSTALLOGRAPHIC TEXTURE AND GRAIN REFINEMENT IN THE ALUMINUM LAYER OF CU-AL-CU TRI-LAYER COMPOSITE DEFORMED BY EQUAL CHANNEL ANGULAR EXTRUSION

Abstract

The present research is concerned with the aluminum layer of a loosely packed tri-layer copperaluminum-copper composite deformed by ECAE process. Electron back scattered diffraction (EBSD), transmission electron microscope, and X-ray technique were employed to investigate the detailed changes occurring in the microtexture, microstructure (cell size and misorientation), and dislocation density evolution during consecutive passes of ECAE process performed on the composite based on route Bc. According to tensile test results, the yield stress of the aluminum layer was increased significantly after application of ECAE throughout the four repeated passes and then slightly decreased. An ultrafine grain size within the range of 500-600 nm was obtained in the Al layer by increasing the thickness of copper layers. It was observed that the reduction of grain size in the aluminum layer is nearly 57% more than that of an ECAE-ed single layer aluminum billet. Also, the grain refinement of the aluminum layer is accelerated throughout 8 passes. This observation was attributed to the higher rate of dislocation interaction, cell formation and texture development during the ECAE of the composite compared to those of the single billet.

Structure Characteristics Affected by Material Plastic Flow in Twist Channel Angular Pressed Al/Cu Clad Composites

“…Generally, the decrease in the grain size is not directly proportional to the imposed strain; decreasing thickness of the reinforcing component supports a decrease in the grain size within this component during processing. However, the application of critical deformation (i.e., imposed strain, the value of which depends on the material) leads to the formation of amorphous structures and saturated solid solutions, regardless of the used technology [29][30][31][32]. Due to the interactions of the individual phases during intensive plastic processing of composites, the achievable grain size for them is generally smaller than for the original single-phase materials; SPD methods are applicable for the preparation of nanocomposites with the average grain sizes of 10 nm [33].…”

Archives of Metallurgy and Materials

“…The Cu alloys, especially CuCr0.6 (C18200) are used in numerous applications where excellent combination of mechanical strength and electrical conductivity is required [1,5,6]. In recent years research on the severe plastic deformation (SPD) processing, structure and mechanical behavior of ultrafine grained (100 nm < d < 1 μm) materials are performed [2,7,8]. The obtained results showed great possibilities for fabricating high-strength and ductile Cu alloys [2,9].…”

“…The obtained microstructure is complex and depend on initial structure (heat treatment conditions) and deformation parameters as: effective strain or deformation mode. Deformation mode has a strong effect on textural hardening [8,10]. Many works dedicated various SPD techniques and conditions present different phenomenological models for development of high angle boundaries and structure refinement [3,10].…”