Evolution of Grain Refinement Mechanism in Cu-4wt.%Ti Alloy during Surface Mechanical Attrition Treatment

Abstract

This work reveals the grain refinement process of low-stacking fault energy Cu-4wt.%Ti alloy during surface mechanical attrition treatment (SMAT). Without phase transformations, the grain refinement process in Cu-4wt.%Ti alloy with a low stacking fault energy involves formation of planar dislocation arrays and twins in the small strain and low strain rate deformed region adjacent to the coarse grain matrix, twin-twin intersections leading to grain subdivision. The formation of lamellae, polygonal grains, and rotation recrystallization were induced by the large strain and high strain rate deformation near the treated surface. We also observed one distinct layer at the treated surface with the thickness about 15 µm, which is filled with equiaxed nanograins. The hardness of the treated surface was increased by 40% and attributed to the grain refinement according to the grain boundary strengthening mechanism.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Grain Boundary Strengthening; Grain Refinement; Mechanical Twining; Nanostructured Materials; Surface Mechanical Attrition Treatment

International Standard Serial Number (ISSN)

0925-8388

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 Elsevier Ltd, All rights reserved.

Publication Date

01 Sep 2018

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