Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
A CONTRIBUTION TO ELECTROCHEMICAL NANOINDENTATION TECHNIQUE
Submission Author:
José Eduardo Silveira Leal , MG
Co-Authors:
José Eduardo Silveira Leal, Teófilo Jacob Freitas e Souza, Sinésio Franco, Vera Lúcia Donizeti de Sousa FRanco, Rosenda Arencibia
Presenter: José Eduardo Silveira Leal
doi://10.26678/ABCM.COBEM2019.COB2019-1419
Abstract
This study aims to adapt a nanoindentation tester (NHT2) for performing the evaluation of the Inconel 718 hydrogen embrittlement (HE) using instrumented nanoindentation. In order to investigate the effect of the hydrogen permeation on the values of nanohardness, plane strain modulus and indentation depth, nanoindentations were performed on the sample of Inconel 718 alloy. To validate the results, ten indentations were performed per condition (with and without hydrogen charge). The hydrogen charging was carried out by using cathodic polarization with the sample submerged in a NaCl 3.5 % aqueous solution. The potential in the sample was applied using a three-electrode configuration. A standard reference electrode of Ag/AgCl was utilized. The specimens were charged under a potential of – 1.2 mV. It was concluded that the hydrogen permeation via cathodic protection produced statistically significant effects on maximum indentation depth (hm) and nanohardmess (HIT) values in the Inconel 718 sample for a 95 % confidence level. Although, there was no significant change in plane strain modulus (E*) values, the average value of the HIT was increased 19.3 % in the presence of cathodic protection. The average values of hm were reduced in 6.1 % with the application of cathodic potential. Hence, for the conditions of this experiment, the Inconel 718 alloy was susceptible to hydrogen embrittlement.
Keywords
electrochemical nanoindentation, Hydrogen embrittlement, Inconel 718, calibration, acoustic enclosure
