Hostname: page-component-77c89778f8-swr86 Total loading time: 0 Render date: 2024-07-20T04:33:49.106Z Has data issue: false hasContentIssue false

Microstructural and mechanical inhomogeneity in the narrow-gap weld seam of thick GMA welded Al–Zn–Mg alloy plates

Published online by Cambridge University Press:  17 November 2016

F.Y. Shu
Affiliation:
Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
Y.M. Sun
Affiliation:
Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
H.Y. Zhao*
Affiliation:
Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
X.G. Song
Affiliation:
Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
Sh.H. Sui
Affiliation:
Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
W.X. He
Affiliation:
Shandong Provincial Key Laboratory of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
P. He
Affiliation:
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
B. Liu
Affiliation:
School of Materials Science and Engineering, Jiangsu University of Scienece and Technology, Zhenjiang 212003, China
B.Sh. Xu
Affiliation:
National Key Laboratory for Remanufacturing, Beijing 100072, China
*
a) Address all correspondence to this author. e-mail: shufengyuan1987@163.com
Get access

Abstract

Inhomogeneity may lead to premature failure and operationally determines the lifetime estimation of thick weld joints. Considerable novelty of this paper was the achievement of the microstructural and mechanical inhomogeneity, especially along the thickness direction, in the narrow-gap weld seam of thick gas metal arc (GMA) welded Al–Zn–Mg alloy plates. The microstructure of the weld seam was investigated by means of optical metallography, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectrum (EDS), after which the phase composition was ascertained according to the x-ray diffraction (XRD) analysis and selected area diffraction analysis by TEM (TEM-SAD). The generation of intergranular short rod-shaped MgZn2 particles changed the distribution of precipitates on the grain boundary with intragranular ellipsoidal MgZn2 particles simultaneously formed as the strengthening phase, which rendered preferable mechanical performances to the bottom layer of the weld seam. The above conclusion was farther affirmed by micro fractography and EDS test results on the fractured surface of the tensile samples. In addition, the effect of following weld passes on the microstructure and micro hardness profile of the finished weld pass was investigated.

Type
Articles
Copyright
Copyright © Materials Research Society 2016 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Amrei, M.M., Monajati, H., Thibault, D., Verreman, Y., Germain, L., and Bocher, P.: Microstructure characterization and hardness distribution of 13Cr4Ni multi-pass weld metal. Mater. Charact. 111, 128 (2016).Google Scholar
Castelluccio, G.M., Perez Ipiña, J.E., Yawny, A.A., and Ernst, H.A.: Fracture testing of the best effected zone from welded steel pipes using an in situ stage. Eng. Fract. Mech. 98, 52 (2013).Google Scholar
Mathers, G.: The Welding of Aluminium and its Alloys (CRC Press, Cambridge, England, 2002); p. 94.Google Scholar
Zhang, Zh.H., Dong, Sh.Y., Wang, Y.J., Xu, B.Sh., Fang, J.X., and He, P.: Microstructure characteristics of thick aluminum alloy plate joints welded by fiber laser. Mater. Des. 84, 173 (2015).Google Scholar
Shu, F.Y., Tian, Z., Lv, Y.H., He, W.X., Lv, F.Y., Lin, J.J., Zhao, H.Y., and Xu, B.Sh.: Prediction of vulnerable zones based on residual stress and microstructure in CMT welded aluminum alloy joint. Trans. Nonferrous Met. Soc. China 25(8), 2701 (2015).Google Scholar
Ma, T. and Den Ouden, G.: Softening behavior of Al–Zn–Mg alloys due to welding. Mater. Sci. Eng., A 266, 198 (1999).CrossRefGoogle Scholar
Devakumaran, K., Ananthapadmanaban, M.R., and Ghosh, P.K.: Variation of chemical composition of high strength low alloy steels with different groove sizes in multi-pass conventional and pulsed current gas metal arc weld depositions. Def. Technol. 11(2), 147 (2015).Google Scholar
Mythili, R., Thomas Paul, V., Saroja, S., Vijayalakshmi, M., and Raghunathan, V.S.: Microstructural modification due to reheating in multi-pass manual metal arc welds of 9Cr–1Mo steel. J. Nucl. Mater. 312, 199 (2003).CrossRefGoogle Scholar
Ma, R., Fang, K., Yang, J.G., Liu, X.S., and Fang, H.Y.: Grain refinement of HAZ in multi-pass welding. J. Mater. Process. Technol. 214, 1131 (2014).CrossRefGoogle Scholar
Vijayanand, V.D., Laha, K., Parameswaran, P., Ganesan, V., and Mathew, M.D.: Microstructural evolution during creep of 316LN stainless steel multi-pass weld joints. Mater. Sci. Eng., A 607, 138 (2014).Google Scholar
Deng, D. and Kiyoshima, S.: Numerical simulation of welding temperature field, residual stress and deformation induced by electro slag welding. Comput. Mater. Sci. 62, 23 (2012).CrossRefGoogle Scholar