Journal Published Online: 16 April 2021
Volume 10, Issue 2

Effect of Axial Load-Dependent Deformation Rate on the Grain Size Distribution and Mechanical Properties of Friction Stir Processed Copper

CODEN: MPCACD

Abstract

During friction stir processing (FSP), the combination of rotation and movement of the tool leads to frictional heat generation and plastic deformation at the tool-material contact surface, leading to a microstructurally refined formation region. The deformation rate in the material can be altered by varying the axial load by increasing or decreasing the tool’s plunging depth. In the present study, FSP was carried out on a pure copper plate of 3-mm thickness by varying the plunge depth from 2.3 to 2.6 mm for a tool pin length of 2.4 mm. The microstructure of the processed samples was studied by optical microscopy, and the grain size was measured by the linear intercept method. Tensile testing was carried out perpendicular to the processing direction. The grain size distribution was narrower at low axial loads and wider at the higher axial loads, measured between 1 and 120 µm. At higher axial loads, microstructure consisted of bands indicative of the heterogeneity in the deformation. The formation of bands at higher axial loads leads to improved mechanical properties. The ductility of the processed materials at higher axial loads was 16%, which was four times the increase observed at lower axial loads (4%). The formation of a bi-modal microstructure (alternating layers of fine and coarse grains) at high axial load enhanced the processed materials’ strength and ductility.

Author Information

Rajendran, Anbukkarasi
Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
Nadammal, Naresh
Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
Singh, Kuldeep
Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
Kailas, Satish V.
Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
Pages: 11
Price: $25.00
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Stock #: MPC20200166
ISSN: 2379-1365
DOI: 10.1520/MPC20200166