Effect of Multiple Laser Shock Peening on the Mechanical Properties of ETP Copper

Page 1

Mechanics, Materials Science & Engineering, July 2017 – ISSN 2412-5954

Effect of Multiple Laser Shock Peening on the Mechanical Properties of ETP Copper1 Ayush Bhattacharya1, Siddharth Madan1, Chirag Dashora1, S. Prabhakaran2, V.K. Manupati1,a, S. Kalainathan2, K.P.K. Chakravarthi3 1 – School of Mechanical Engineering, VIT University, Vellore, Tamil Nadu, India 2 – Centre for Crystal Growth, VIT University, Vellore, Tamil Nadu, India 3 – Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India a – manupativijay@gmail.com

DOI 10.2412/mmse.77.9.503 provided by Seo4U.link

Keywords: laser shock peening, ETP copper, mechanical properties, ultimate tensile strength, elongation.

ABSTRACT. The study conducted proposes the effect of multiple laser shock peening (LSP) on ETP copper alloy plates, with a low energy laser to investigate the changes in the mechanical properties of the material. In this paper, a study of the microstructure, micro hardness and surface morphology has been conducted on the parent sample, and the laser peened sample. The aim of this current research work is to investigate the changes in the mechanical properties of ETP Copper after LSP and to study the changes in the microstructure, micro hardness, tensile strength, elongation and surface morphology of the laser peened sample, and comparing it with the parent sample.

Introduction. Electrolytic Tough Pitch (ETP) copper has long been the standard type of commercial wrought copper used in the production of sheet, plate, bar, strip, and wire. It is widely used in the automotive and aerospace sectors, due to its engineering material, owing to its excellent corrosion resistance, good ductility as well as high thermal and electrical conductivity. The motivation of this research work drawn from the fact that this material has its potential to be used for the fabrication of heat sinks in International Thermonuclear Experimental Reactor (ITER) applications. Although ETP copper is not 100% oxygen free, it is considered OFC (oxygen free copper) because it has a minimum conductivity rating of 100% IACS (International Annealed Copper Standard) while the minimum rating to consider OFC is 99.9% pure. Laser shock Peening (LSP) is a surface enhancement process used to enhance the properties of a material surface. The basic mechanism involved in this process is to create compressive residual stresses to a certain depth in the material which helps delay the premature failures. These deep, high magnitude compressive residual stresses modify the surface hardness and microstructure, therefore, improving different properties of the material such as strength and wear, corrosion and fatigue resistances. The principle involved in laser peening involves a laser pulse with a duration of several nano-seconds is focused on a material surface. The material surface evaporates instantly by ablative interaction. The evaporating material is limited by water, and the resulting high-density metallic vapor is ionized to form a plasma by inverse bremsstrahlung. The absorbed laser energy, in the plasma, generates a heat-sustained shock wave and impinges on the material with an intensity of several gigapascals, far higher than the yield strength of most materials. The shock wave propagates through the material losing energy thus creating a permanent strain. Once after propagation of the shock wave, the strained region is elastically constrained to form compressive residual stresses on the surface. 1

© 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

MMSE Journal. Open Access www.mmse.xyz


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.
Effect of Multiple Laser Shock Peening on the Mechanical Properties of ETP Copper by MMSE Journal - Issuu