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Effect of Pulse Duration on Corrosion and Impression Creep Properties of AA5083‐H111 Al–Mg Alloy Weldments Processed by P‐GTAW
Author(s) -
Umar Mustafa,
Sathiya Paulraj
Publication year - 2018
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201701147
Subject(s) - materials science , creep , corrosion , intermetallic , metallurgy , grain boundary , pulse duration , alloy , dissolution , microstructure , chemical engineering , laser , physics , optics , engineering
In this work, the corrosion and impression creep properties of weldments are determined using potentiodynamic polarization test and impression creep test. It is evident that the shorter pulse duration results in comparatively finer grains and reduces the loss of magnesium in fusion zone, which facilitates an increase in precipitation of anodic β ‐phase (Al 3 Mg 2 ) and Mg 2 Si particles in the grain boundaries. It leads to the formation of pits by dissolving Mg atoms and propagate along the interdendritic region and finally corrode the surface thoroughly. On contrary, the increase in pulse duration results in uniform distribution of iron‐rich Al 6 (Fe,Mn) intermetallics as well as Fe and Mn particles in the interdendritic region which induce localized cathodic reaction and these localized cathodes assisted in achieving noble corrosion resistance by increasing the width of passive region. Also, an increase in creep resistance is attained with an increase in activation energy at a temperature of 573 K owing to the uniform dispersion of iron‐rich Al 6 (Fe,Mn) intermetallics in the grain boundaries of weldments processed with longer pulse duration. Hence, it is inferred from this research that the rise in pulse duration improves the corrosion and creep resistance of weldments by altering the morphology and surface distribution of intermetallics.