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A new technique to produce ultra-fine grained tubular specimen has been proposed,and the experiments have been performed using equal channel angular pressing(ECAP) with an angle of 90° between two intersecting channels and also the use of rubber pad as a mandrel during process.Commercial purity copper tubes have been pressed up to three passes through four different fundamental routes(A,B_A,B_C,and C) directions of which are identified in the text below.The influence of each route on the value,distribution,and homogeneity of hardness has been investigated by applying Vickers micro-hardness measurements at various locations of the tube’s transverse planes.Significant enhancement of the hardness is observed after the first pass ECAP.Also,routes C and B_C show,respectively,better average hardness magnitude and hardness distribution uniformity.In addition,the results indicate that there is about 50%and 62%reduction of the grain size,compared to the annealed condition,following ECAP process of the copper tube sample after the first and the third pass via route B_C.
A new technique to produce ultra-fine grained tubular specimen has been proposed, and the experiments have been performed using equal channel angular pressing (ECAP) with an angle of 90 ° between two intersecting channels and also the use of rubber pad as a mandrel during process. Commercial residual copper tubes have been pressed up to three passes through four different fundamental routes (A, B_A, B_C, and C) directions of which are identified in the text below. The influence of each route on the value, distribution, and homogeneity of hardness has been investigated by applying Vickers micro-hardness measurements at various locations of the tube’s transverse planes. Identification Enhancement of the hardness is observed after the first pass ECAP. Also, routes C and B_C show, respectively, better average hardness magnitude and hardness distribution uniformity. In addition, the results indicate that there is about 50% and 62% reduction of the grain size, compared to the annealed condition, following ECAP proces s of the copper tube sample after the first and the third pass via route B_C.