Metallurgical and Materials Transactions A

, Volume 41, Issue 8, pp 2010–2021

Effect of Heat Input Conditions on Microstructure and Mechanical Properties of Friction-Stir-Welded Pure Copper


DOI: 10.1007/s11661-010-0254-y

Cite this article as:
Xue, P., Xie, G., Xiao, B. et al. Metall and Mat Trans A (2010) 41: 2010. doi:10.1007/s11661-010-0254-y


Defect-free friction stir welds of 5-mm-thick pure copper plates were produced in relatively low heat input conditions. The characteristics of the microstructure and mechanical properties of the welded joints were investigated. The stir zone (SZ) exhibited equiaxed recrystallized grains, whose size decreased as the heat input was decreased. The percentage of high-angle grain boundaries (grain boundary misorientation angle >15 deg) in the SZ was quite high (90.2 to 94.5 pct) and increased as the heat input was increased. When the heat input was decreased, the percentage of the twin boundaries (TBs) dropped, and the number of the twin lamellas was reduced. Under a very low heat input condition, the typical characteristics of thermomechanically affected zone (TMAZ) were discernible; however, the TMAZ was characterized by a recrystallized grain structure at higher heat input conditions. The grains in the heat-affected zone (HAZ) were slightly coarsened compared to those in the parent material (PM), but the grain size varied a little under different parameters. The hardness of the SZ increased as the heat input was increased, and the lowest hardness appeared at the HAZs where the welds failed. The ultimate tensile strength (UTS) was similar to that of the PM under various heat input conditions, but the yield strength (YS) and elongation were lower. The YS increased as the lowest hardness value increased, and the elongation decreased due to the enhanced strain localization.

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2010

Authors and Affiliations

  1. 1.Shenyang National Laboratory for Materials Science, Institute of Metal ResearchChinese Academy of SciencesShenyang110016P.R. China
  2. 2.State Key Laboratory of Rolling and AutomationNortheastern UniversityShengyangP.R. China
  3. 3.School of Materials Science and EngineeringHarbin Institute of TechnologyHarbinP.R. China

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