INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING-GREEN TECHNOLOGY Vol. 3, No. 2, pp. 161-165 APRIL 2016 / 161 © KSPE and Springer 2016 Study of Electrically-Assisted Indentation for Surface Texturing Hyun-Seok Oh 1 , Hak-Rae Cho 1 , Hani Park 1 , Sung-Tae Hong 1 , and Doo-Man Chun 1,# 1 School of Mechanical Engineering, University of Ulsan, 93, Daehak-ro, Nam-gu, Ulsan, 44610, South Korea # Corresponding Author / Email: dmchun@ulsan.ac.kr, TEL: +82-52-259-2706, FAX: +82-52-259-1680 KEYWORDS: Electrically-Assisted indentation, Vickers hardness, Electric current Electrically-Assisted manufacturing is a promising hybrid manufacturing process for improved ductility and elongation during plastic deformation of metals and decreased spring-back. Most studies have focused on the deformation of a whole material by applying electric current through the whole material, and many electrically-assisted manufacturing processes including forging, rolling, and sheet metal forming have been introduced. However, plastic deformation processes on a surface, such as indentation, embossing, and scribing, are also important for functional surface texturing and marking, among other uses. In this study, the effect of a continuous electric current on indentation in stainless steel and titanium was investigated using Vickers hardness test. The hardness was decreased by the electric current during indentation with a diamond tip. The amount of decreased hardness depended on the amplitude of the electric current and the positions of two electrodes. The electric current density passing through the surface was calculated by finite element analysis, and the hardness decrease was proportional to the electric current density. Manuscript received: January 14, 2016 / Revised: March 13, 2016 / Accepted: March 16, 2016 1. Introduction Hybrid manufacturing processes are combinations of manufacturing processes used to produce products in more efficient, effective and productive ways, and there are various different hybrid manufacturing processes. 1-3 Hybrid manufacturing processes can include assisted processes 4-8 or mixed processes 9-12 in order to combine different energy sources or tools. Electrically-Assisted Manufacturing (EAM) is a hybrid manufacturing process that utilizes electric current, mainly during the plastic deformation of metals and their alloys, to improve productivity, efficiency, and quality at relatively lower temperatures compared to hot working. The mechanical properties of metals and their alloys can change temporarily or permanently under the application of electric currents during plastic deformation. This phenomenon is often referred to as electroplasticity. However, electric currents can cause thermal effects by Joule heating as well as athermal effects by electroplasticity. 13 EAM processes have been widely utilized in various different manufacturing processes mainly associated with bulk deformation and sheet-metal forming. Electrically-Assisted (EA) forging, EA rolling, and EA drawing as bulk deformation processes could increase deformability and reduce flow stress. 14-16 EA bending, EA deep drawing, and stretch forming as sheet-metal forming could increase deformability and reduce flow stress and springback. 17-19 Most studies have applied electric current through the whole workpiece, and these were effective for bulk deformation and sheet metal forming. However, this approach is not suitable for local plastic deformation processes such as coining, embossing, and surface texturing. In addition, some researchers have used tools or dies as electrodes to minimize power consumption and unwanted heating. However, tools or dies can easily experience Joule heating and electroplasticity with electric currents. 15,19,20 NOMENCLATURE E = Electric energy (J) I = Electric current (A) R = Resistance (Ω ) t = Time duration of electric current (sec) ñ = Specific resistance (Ω ·m) l = Distance (m) A = Area (m 2 ) V = Volume (m 3 ) DOI: 10.1007/s40684-016-0020-8 ISSN 2288-6206 (Print) / ISSN 2198-0810 (Online)