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Journal of Materials Science

, Volume 42, Issue 16, pp 6651–6657 | Cite as

Effect of laser beam welding on fracture toughness of a Ti-6.5Al-2Zr-1Mo-1V alloy sheet

  • Yaowu ShiEmail author
  • Fei Zhong
  • Xiaoyan Li
  • Shuili Gong
  • Li Chen
Article

Abstract

Investigation of fracture toughness on Ti-6.5Al-2Zr-1Mo-1V alloy thin sheet and its laser-welded joints has been carried out. In the test compact tension (CT) specimens and single specimen technology were used. In addition, hardness distribution and microstructure of the welded joints were examined. Fracture test indicates that brittle unstable fracture occurs after slow crack propagation for all the specimens, except that one heat affected zone (HAZ) specimen is brittle crack initiation. It is found that rolling directions have no obvious effect on fracture toughness of base metal. Moreover, fracture toughness of weld metal is obviously decreased in comparison with base metal whatever in as-welded condition or in stress relief condition. Post-weld heat treatment (PWHT) leads to fracture toughness of the welds further decreasing. Fractography observation shows that the fracture mode is predominantly dimpled in base metal. However, there exists intergranular fracture in the weld metal. Thus, the transition of fracture mode from both base metal and HAZ to weld metal may lead to dramatic decrease in fracture toughness. Microstructure examination reveals that the microstructure of weld metal consists of large grains with fine acicular structure. The formation of fine α acicular structure is due to rapid cooling during laser welding. After PWHT, the acicular structure is coarsened.

Keywords

Welding Fracture Toughness Base Metal Weld Metal Fusion Zone 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgement

The authors would like to express their thanks to the financial support from the State Defence Key Laboratory For High Energy Density Beam Processing Technology.

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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Yaowu Shi
    • 1
    Email author
  • Fei Zhong
    • 1
  • Xiaoyan Li
    • 1
  • Shuili Gong
    • 2
  • Li Chen
    • 2
  1. 1.School of Materials Science and EngineeringBeijing University of TechnologyBeijingP.R. China
  2. 2.State Defence Key Laboratory For High Energy Density Beam Processing Technology, Beijing Aeronautical Manufacturing Technology Research InstituteBeijingP.R. China

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