Investigation on wear and corrosion behavior of equal channel angular pressed aluminium 2014 alloy

S P Divya,G Yoganandan,S A Srinivasan,B Ravisankar,J N Balaraju,M Nagaraj

doi:10.1088/1757-899x/314/1/012024

Abstract

Aluminium 2014 alloy solutionized at 495°C, aged at 195°C was subjected to Equal Channel Angular Pressing (ECAP). Dry sliding wear tests were conducted using pin on disc tribometer system under nominal loads of 10N and 30N with constant speed 2m/s for 2000m in order to investigate their wear behavior after ECAP. The Co-efficient of friction and loss in volume were decreased after ECAP. The dominant wear mechanism observed was adhesion, delamination in addition to these wear mechanisms, oxidation and transfer of Fe from the counter surface to the Al 2014 pin were observed at higher loading condition. The corrosion behavior was evaluated by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The results obtained from PDP showed higher corrosion potential and lower corrosion density after ECAP than base. Electrochemical impedance spectroscopy (EIS) showed higher charge transfer resistance after ECAP. Surface morphology showed decreased pit size and increased oxygen content in ECAP sample than base after PDP.

Highlights

Equal Channel Angular Pressing is one of the emerging severe plastic deformation (SPD) techniques that improve mechanical and micro structural properties without changing the dimension of bulk unlike cold working, coating, surface treatments etc
Since Equal Channel Angular Pressing (ECAP) tailors mechanical properties by the formation of ultrafine grains, equal importance must be given to their corrosion behavior, in aluminum alloys where a protective oxide film imparts corrosion resistance
After electrochemical impedance spectroscopy (EIS) the system was allowed to reach steady state and potentiodynamic polarization (PDP) tests were performed by scanning the electrode from -200mV to 200mV with respect to OCP

Summary

Introduction

Equal Channel Angular Pressing is one of the emerging severe plastic deformation (SPD) techniques that improve mechanical and micro structural properties without changing the dimension of bulk unlike cold working, coating, surface treatments etc. For past decade EACP is efficiently employed for various alloys of aluminum to improve their properties by making it ultrafine grained material. ECAP improves hardness and tensile strength of Al 2014 alloy which has been reported [1]. Since ECAP tailors mechanical properties by the formation of ultrafine grains, equal importance must be given to their corrosion behavior, in aluminum alloys where a protective oxide film imparts corrosion resistance. It has been reported that ECAP processing decreases the corrosion resistance of the base material due to high grain boundary area, internal stress, increased dislocation density and second phase that provide more sites to initiate corrosion [3]. Reports are available to explain the improved corrosion resistance due to ECAP processing [4]. Systematic study on the corrosion and wear behavior of aluminum alloys will be helpful to extend the knowledge on the frictional characteristics

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Conclusion