Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Rafał Molak"

Influence of the corrosive environment on the Portevin-Le Chatelier plastic instability phenomenon in Al-1Mg and Al-3Mg model alloys DOI:10.15199/28.2016.3.1

  The aim of this work was to indicate the influence of changes on the surface of materials caused by the corrosive medium (3.5% NaCl solution) on the intensity and character of the Portevin-Le Chatelier effect in model aluminium alloys. For this purpose, two Al alloys, containing 1% and 3% of magnesium, were subjected to tensile testing in the as-cast state and after the exposition in NaCl solution for various time. Several electrochemical measurements were held to determine materials’ corrosive behaviour and microscopic observations to evaluate the surface character of the samples. High corrosion resistance of the materials resulted in a very slight alteration of their surface development, which didn’t lead into any significant variations in the plastic instability phenomenon PLC. Key words: Portevin-Le Chatelier effect, aluminium alloys, plastic instability, corrosion. 1. INTRODUCTION Portevin-Le Chatelier effect (PLC effect) is a well-known phenomenon occurring in many aluminium alloys during deformation [1], manifesting itself in a form of characteristic serrations on the stress-strain curve, caused by rapid changes of force in small extensions. It can lead to inhomogeneous deformations in materials microstructure, resulting in the deterioration of its mechanical properties [2]. Apart from the most commonly analysed structural factors, like grain size, precipitations or texture, there are some extrinsic ones which can also strongly influence materials vulnerability to PLC effect [3]. Abduluyahed in his research [4, 5] compared serrated flow in 316 and 316L austenitic steels during tensile testing in air and in vacuum. He reported a considerable decrease in serration frequency in vacuum conditions, which can be subjected to the fact that there is no oxygen layer on the surface, which could crack during deformation and work as a stress concentration. Temperature was considered as a factor influencing PLC effect, by Yilm[...]

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