Microstructural Characterizations of Cu Processed by ECAP from 4 to 24 Passes

Abstract

The microstructures of pure Cu processed by equal channel angular pressing (ECAP) from 4 to 24 passes were investigated. It was found that the microstructures of Cu samples with a small number of ECAP passes (4-8) were not inhomogeneous and the fraction of high-angle grain boundary (HAGB) was low (25~43%). While for the samples with many number of ECAP passes (12-24), the grains became more equiaxed-like and the GB misorientations exhibited double-peak distribution with high fraction (51~64%) of HAGB. It was dislocation cells formed in large grains of the few-pass samples, but subgrains in the many-pass samples. These characterizations suggested that ultrafine-grained (UFG) microstructures in the few-pass samples were not fully accomplished, while it was obtained after many passes (>12). It is believed that dynamic recovery during processing for many passes was attributed to the formation of UFG microstructures.

Intrinsic high cycle fatigue behavior of ultrafine grained pure Cu with stable structure

“…1c. Differences from the SPD Cu, which has a low ratio of HAGBs (~60%) [26,27], a high ratio of HAGBs (85%), can be obtained in FSP Cu, which is in accordance with other FSP UFG materials [18][19][20][21][22]. Furthermore, the grain boundary distribution of FSP Cu is close to the random distribution of a cubic metal, as shown in Fig.…”

Microstructure and mechanical properties of Cu and Cu–Zn alloys produced by equal channel angular pressing

“…After this stage, continuing pressing will mainly help to homogenize the microstructure and enhance the misorientation of grain boundaries rather than diminish the grain size. So the proportion of HAGBs increases monotonously during the whole ECAP processing, which can be used to characterize the degree of grain refinement progress [37]. Fig.…”

Application of Severe Plastic Deformation Techniques to Magnesium for Enhanced Hydrogen Sorption Properties

“…ECAP is quite efficient in processing metals and allows to produce porosity-free materials in substantial quantities with lower concentration of impurities and at a lower cost than ball-milling [25]. Through the crystallite size refinement process, the proportion of high angle grain boundary (HAGB) increases due to dislocations recovery [26]. High texturation effects could also be introduced by this process, thus organizing specific grain boundaries distributions, indeed depending on the crystal symmetry of the processed system (e.g., cubic versus hexagonal).…”