Experimental Investigation of the Effect of Equal Channel Angular Pressing Intermediate Canal of on the Mechanical Properties of Copper

The aim of this article is to investigate the effect of Equal Channel Angular Pressing (ECAP) intermediate on the mechanical and microstructure properties of pure copper. For this purpose, three molds with internal angles of 65, 75 and 90 degree were designed and made and copper samples were examined for all these molds during 4 passes of extrusion. The results of the investigation of copper microstructure showed that by increasing the number of extrusion passes, the structure of copper in all molds was changed from micrometer to nanometer. The greatest reduction in the microstructure of the copper metal was related to the mold with a 65 degree internal channel angle and the lowest was 90 °. The hardness changes of the workpiece showed that significant increase compared to the neat sample due to the more applied force and shear strain by the mold body. After the fourth pass extrusion measured hardness at 90, 75 and 65 degrees, where 141, 138 and 131 HB, respectively. The results of the tensile test showed that by decreasing the angle of the mold channel from 90, 75 and 65 degrees, the ultimate tensile strength of the final extruded parts increased by 23, 29 and 31 percent, respectively, relative to the raw material. The fatigue life of the ECAPed sample in the mold with an angle of 65 degrees had a 1700% improvement. ECAPed parts with a 90- and 75-degree angle improved lifetime by 1400 and 1500% times, respectively.