Comparison of the Microstructures and Mechanical Properties in the Overlapping Region of Low Carbon Steel Additive Bead Fabricated by WAAM and FSP

Viswanath, C. (2023) Comparison of the Microstructures and Mechanical Properties in the Overlapping Region of Low Carbon Steel Additive Bead Fabricated by WAAM and FSP. Metallurgical and Materials Transactions A, 54 (3). pp. 869-895. ISSN 1073-5623

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Abstract

The periodic structural characteristics of the grains in the overlapping region of the WAAM deposited additive bead translate into spatially dependent local anisotropic mechanical properties. At the fusion boundary, the epitaxial growth causes the formation of columnar grains due to the high temperature gradient (G)/growth rate (R) ratio. As the solidification progresses to the centre of the overlapping region, the cooling rate decreases/or has a low value of G/R ratio. The grain structure changes to irregular lath-type morphology. After friction stir processing (FSP), the solidification microstructures are refined and have equiaxed grain morphology. The presence of E,E¯,J,J¯,andF shear components have been observed along with the cube and γ —fiber texture components. The presence of the two major components {111} < 112 > and {111} < 110 > of the γ —fiber confirms the improvement in the percent elongation/formability of the overlapping region. The geometric necessary dislocations (GNDs) appearing around ferrite/cementite interface and near to the grain boundaries (GBs), the dislocation pinning by the sub-micron/nanoscale cementite particles via Orowan looping, and dynamic recovery associated networks/or subgrain boundaries formation are the main reasons for the three stages of work hardening rate (θ=dσdε).

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IITH Creators:

IITH Creators	ORCiD
Viswanath, C.	UNSPECIFIED

Item Type:

Article

Uncontrolled Keywords:

Carbides; Friction stir welding; Grain boundaries; Low carbon steel; Morphology; Solidification; Strain hardening; Textures; Anisotropic mechanical properties; Columnar grain; Friction stir processing; Fusion boundary; Low-carbon steels; Microstructures and mechanical properties; Overlapping regions; R ratio; Structural characteristics; γ fibers; Additives

Subjects:

Physics > Mechanical and aerospace

Divisions:

Department of Mechanical & Aerospace Engineering

Depositing User:

Mr Nigam Prasad Bisoyi

Date Deposited:

27 Aug 2023 11:42

Last Modified:

27 Aug 2023 11:42

URI:

http://raiithold.iith.ac.in/id/eprint/11645