Characterization of microstructure and mechanical properties of friction stir welded AlMg5- Al2O3 nanocomposites

In the present study, powder metallurgy processed unmilled AlMg5, milled AlMg5 and milled AlMg5-0.5vol% Al2O3 nanocomposite have been successfully friction stir welded (FSW). The effect of friction stir welding on the evolution of weld microstructures; hardness and tensile properties were studied an...

Full description

Saved in:
Bibliographic Details
Published in:Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2016-03, Vol.658, p.109-122
Main Authors: Babu, N. Kishore, Kallip, Kaspar, Leparoux, Marc, AlOgab, Khaled A., Reddy, G.M., Talari, M.K.
Format: Article
Language:English
Subjects:
Aluminum base alloys
Aluminum oxide
Base metal
Friction stir welding
Hardness
Mechanical properties
Microstructure
Nano-composites
Recrystallisation
Reinforcement
Tensile strength
Welded joints
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In the present study, powder metallurgy processed unmilled AlMg5, milled AlMg5 and milled AlMg5-0.5vol% Al2O3 nanocomposite have been successfully friction stir welded (FSW). The effect of friction stir welding on the evolution of weld microstructures; hardness and tensile properties were studied and discussed in detail. FSW of unmilled AlMg5 resulted in significant grain refinement and strain hardening in the nugget zone induced by the thermo-mechanical processing, thereby increasing the stir zone hardness and tensile strengths to 100HV and 324MPa when compared to 80 HV and 300MPa of base metal, respectively. In contrast, the FSW of milled AlMg5 and milled AlMg5-0.5vol% Al2O3 samples showed a reduction in UTS values to 375MPa and 401MPa in the stir zone compared to 401MPa and 483MPa of respective base metal values. Transmission electron microscopic (TEM) investigation of weld stir zones revealed the homogenous distribution of Al4C3 nanophases in milled AlMg5 and Al2O3 nanoparticles in milled AlMg5-0.5vol% Al2O3 samples throughout the aluminium matrix. It was revealed that the pre-stored energy from the prior ball milling and hot pressing processes, higher deformation energy and grain boundary pinning effect due to the presence of reinforcement particles has resulted in a higher recrystallization tendency and retarded grain growth during FSW of milled samples. The welds prepared with milled AlMg5-0.5vol% Al2O3 exhibited higher hardness and tensile strength in the stir zone when compared to all other conditions which was attributed to Hall Petch effect due to fine grain size and Orowan strengthening effect due to Al2O3 reinforcements.
ISSN:0921-5093
1873-4936
DOI:10.1016/j.msea.2016.01.102