_Article_  
Effect of Equal Channel Angular Pressing (ECAP) on Erosion-Corrosion of Pure Copper  
[PERSON] 1,2,* 2, [PERSON] 1, [PERSON] 1 and [PERSON] 3  
Mechanical Engineering Department, Qassim University, Buraidah 51452, Saudi Arabia; [PERSON]DDRESS] (F.A.-M.J.; [EMAIL_ADDRESS] (Y.A.-S.)  
Production Engineering Department, Beni Suief University, Beni Suief 62764, Egypt  
Mechanical Engineering Department, Prince Mohammed Bin Fahd University, Al Khobar 31952, Saudi Arabia; [PERSON]SS]  
Correspondence: [EMAIL_ADDRESS]; Tel.: +966-556-280-516  
Different severe plastic deformation (SPD) techniques are applied to refine the microstructure and produce (UFG) and (NS) materials [2; 3; 4]. There are three different SPD categories: bulk, sheet, and tube. Equal channel angular pressing (ECAP) is considered the most popular SPD technique used for bulk materials. It has gained much attention due to the simplicity of die design and manufacturing, as well as low cost. This method has been widely applied on different materials [5; 6; 7]. Many researchers investigated the effect of ECAP on the mechanical properties of various metals [8; 9; 10; 11; 12; 13; 14; 15; 16]. On the other hand, erosion-corrosion (E-C) is an interaction effect of erosion and corrosion, including liquid erosion and cavitation. The interaction of E-C leads to a metal loss that would increase significantly beyond that the separate effect of erosion or corrosion [17; 18; 19; 20]. The E-C rate is measured in accordance with ASTM G119 [21]. The following equations relate the different parameters to total E-C rate [22]:  
\[T=W_{o}+C_{o}+S \tag{1}\]  
\[S=\Delta W_{C}+\Delta C_{W} \tag{2}\]  
where \(T\) is the total E-C rate, \(W_{o}\) is the wear rate due to mechanical erosion, \(C_{o}\) is the rate of corrosion, S is the combined effect of both erosion and corrosion, \(\Delta W_{C}\) is the change in erosion wear rate due to corrosion, and \(\Delta C_{W}\) is the change in corrosion rate due to erosion:  
\[\Delta C_{W}=W_{C}-C_{o} \tag{3}\]  
Equations (1) and (3) can be combined as follows [22]:  
\[\Delta Wc=T-W_{o}-C_{W} \tag{4}\]  
E-C was studied under various conditions on many materials such as steel, AISI 420 stainless steel, AISI 1020 carbon steel, cast iron, aluminum, and copper alloys [23; 24; 25; 26]. The previous researchers found that the material loss due to E-C is mainly affected by experiment duration, slurry flow velocity, impacting angle, erodent particle size, and solid particles concentration [27; 28; 29; 30; 31; 32; 33]. It is reported that the combined effect of erosion and corrosion together represents almost \(40-60\%\) of the total weight loss [34]. Copper and its alloys are useful in many industrial applications, such as seawater piping, shipbuilding, fuel lines, and heat exchangers. There are many studies on UFG/NS copper to fully understand and determine the mechanical and surface properties. However, the available literature showed a lack of research on the effect of ECAP on the surface properties and E-C resistance of pure copper. The effect of the slurry velocity on ECAPed copper was studied previously [24]. The aim of the current work is to investigate the ECAP effects on the E-C resistance of copper under various conditions. Furthermore, improvements of the surface roughness and the E-C resistance of commercial pure copper are intended. For this purpose, four passes of ECAP were performed at room temperature to produce UFG copper samples. The hardness variation due to ECAP passes was investigated. Subsequently, the E-C experiments by the slurry pot method were conducted for parameters such as duration time, slurry flow velocity, impacting angle, and solid particle concentration. By studying the E-C behaviors of copper before and after ECAP, it is expected that the results will offer a solution to improve the E-C resistance of wide range of face centered cubic (FCC) materials, since the ECAP process can be applied on wide range of materials.