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Research Papers

Microstructure and Fatigue Property of Ti–6Al–4V by Ultrahigh Frequency Pulse Welding

[+] Author and Article Information
Mingxuan Yang

School of Mechanical
Engineering and Automation,
Beijing University of
Aeronautics and Astronautics,
No. 37, Xueyuan Road,
Haidian District,
Beijing 100191, China
e-mail: yangmingxuan@buaa.edu.cn

Hao Zheng, Bojin Qi

School of Mechanical
Engineering and Automation,
Beijing University of
Aeronautics and Astronautics,
No.37, Xueyuan Road,
Haidian District,
Beijing 100191, China

Zhou Yang

Department of Mechanical Engineering,
Tsinghua University,
Beijing 100084, China

1Corresponding author.

Manuscript received March 10, 2016; final manuscript received September 30, 2016; published online November 9, 2016. Assoc. Editor: Wayne Cai.

J. Manuf. Sci. Eng 139(4), 041015 (Nov 09, 2016) (8 pages) Paper No: MANU-16-1156; doi: 10.1115/1.4035036 History: Received March 10, 2016; Revised September 30, 2016

Butt welding tests of 1.5 mm thickness Ti–6Al–4V were treated by conventional gas tungsten arc welding (C-GTAW) and ultrahigh frequency pulse GTAW (UHFP-GTAW). The low cycle fatigue (LCF) experiments were conducted on the welded joints. The results of fatigue experiment showed that the number of fatigue cycles was increased with UHFP-GTAW. Changes in the microstructure resulting from reduced heat input were expected to enhance the fatigue propagation resistance. The morphology of the martensites in fusion zone was smaller compared to C-GTAW process, and a larger distribution density of basketweave structure was also obtained by UHFP-GTAW. Furthermore, the decreased fatigue crack rate was accompanied as the increased grain boundaries produced by the reduced grain size in fusion zone. Observation of fatigue fractographs revealed that the UHFP-GTAW has obvious slip traces at fatigue initiation sites and more deep secondary cracks in the crack propagation regions associated with the smaller dimples of final fracture zones. The proportion of propagation regions was much larger than C-GTAW. As a result, it can be considered as the representation of the improvement in ductility.

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References

Boyer, R. R. , 1996, “ An Overview on the Use of Titanium in the Aerospace Industry,” Mater. Sci. Eng.: A, 213(1–2), pp. 103–114. [CrossRef]
Nandan, R. , DebRoy, T. , and Bhadeshia, H. K. D. H. , 2008, “ Recent Advances in Friction-Stir Welding Process, Weldment Structure and Properties,” Prog. Mater. Sci., 53(6), pp. 980–1023. [CrossRef]
Short, A. B. , 2009, “ Gas Tungsten Arc Welding of α + β Titanium Alloys: A Review,” Mater. Sci. Technol., 25(3), pp. 309–324. [CrossRef]
Schaffer, J. P. , Saxena, A. , Antolovich, S. D. , Sanders, T. H., Jr. , and Warner, S. B. , 1999, The Science and Design of Engineering Materials, 2nd ed., McGraw-Hill, New York, p. 399.
Balasubramanian, T. S. , Balasubramanian, V. , and Manickam, M. A. M. , 2011, “ Fatigue Crack Growth Behaviour of Gas Tungsten Arc, Electron Beam and Laser Beam Welded Ti-6Al-4V Alloy,” Mater. Des., 32(8–9), pp. 4509–4520. [CrossRef]
Liu, J. , Gao, X. L. , Zhang, L. J. , and Zhang, J. X. , 2014, “ A Study of Fatigue Damage Evolution on Pulsed Nd:YAG Ti-6Al-4V Laser Welded Joints,” Eng. Fract. Mech., 117, pp. 84–93. [CrossRef]
Wang, X. D. , Shi, Q. Y. , Wang, X. , and Zhang, Z. L. , 2010, “ The Influences of Precrack Orientations in Welded Joint of Ti-6Al-4V on Fatigue Crack Growth,” Mater. Sci. Eng.: A, 527(4–5), pp. 1008–1015. [CrossRef]
Radaj, D. , 1997, Heat Effects of Welding: Temperature Field, Residual Stress and Distortion, 1st ed., D. J. Xiong , C. Y. Zheng , and Y. W. Shi , eds., China Machine Press, Beijing, China, p. 334.
Ravichandran, K. S. , 1991, “ Near Threshold Fatigue Crack Growth Behavior of a Titanium Alloy: Ti-6A1-4V,” Acta Metall. Mater., 39(3), pp. 401–410. [CrossRef]
Yoder, G. R. , and Eylon, D. , 1979, “ On the Effect of Colony Size on Fatigue Crack Growth in Widmanstätten Structure α+β Titanium Alloys,” Metall. Trans. A, 10(11), pp. 1808–1810. [CrossRef]
Yang, X. G. , Li, S. L. , and Qi, H. Y. , 2014, “Ti-6Al-4V Welded Joints via Electron Beam Welding: Microstructure, Fatigue Properties, and Fracture Behavior,” Mater. Sci. Eng.: A, 597, pp. 225–231. [CrossRef]
Tsay, L. W. , and Tsay, C. Y. , 1997, “ The Effect of Microstructures on the Fatigue Crack Growth in Ti-6Al-4V Laser Welds,” Int. J. Fatigue, 19(10), pp. 713–720. [CrossRef]
Murthy, K. K. , and Sundaresan, S. , 1997, “ Fatigue Crack Growth Behavior in a Welded α-β Ti-Al-Mn Alloy in Relation to Micro Structural Features,” Mater. Sci. Eng.: A, 222(2), pp. 201–211. [CrossRef]
Balasubramanian, M. , Jayabalan, V. , and Balasubramanian, V. , 2008, “ Developing Mathematical Models to Predict Tensile Properties of Pulsed Current Gas Tungsten Arc Welded Ti-6Al-4V Alloy,” Mater. Des., 29(1), pp. 92–97. [CrossRef]
Reddy, G. M. , Gokhale, A. A. , and Rao, K. P. , 1998, “ Optimisation of Pulse Frequency in Pulsed Current Gas Tungsten Arc Welding of Aluminium–Lithium Alloy Sheets,” Mater. Sci. Technol., 14(1), pp. 61–66. [CrossRef]
Kishore, B. N. , Ganesh, S. R. S. , Mythili, R. , and Saroja, S. , 2007, “ Correlation of Microstructure With Mechanical Properties of TIG Weldments of Ti-6Al-4V Made With and Without Current Pulsing,” Mater. Charact., 58(7), pp. 581–587. [CrossRef]
Sundaresan, S. , Ram, G. D. J. , and Reddy, G. M. , 1999, “ Microstructural Refinement of Weld Fusion Zones in a–α-β Titanium Alloys Using Pulsed Current Welding,” Mater. Sci. Eng.: A, 262(1–2), pp. 88–100. [CrossRef]
DebRoy, T. , and David, S. A. , 1995, “ Physical Processes in Fusion Welding,” Rev. Mod. Phys., 67(1), pp. 85–112. [CrossRef]
Yang, M. X. , Qi, B. J. , Cong, B. Q. , Liu, F. J. , Yang, Z. , and Chu, P. K. , 2013, “ Study on Electromagnetic Force in Arc Plasma With UHFP-GTAW of Ti-6Al-4V ,” IEEE Trans. Plasma Sci., 41(9), pp. 2561–2568. [CrossRef]
Yang, M. X. , Qi, B. J. , Cong, B. Q. , Liu, F. J. , and Yang, Z. , 2013, “ Effect of Pulse Frequency on Microstructure and Properties of Ti-6Al-4V by Ultrahigh-Frequency Pulse Gas Tungsten Arc Welding,” Int. J. Adv. Manuf. Technol., 68(1), pp. 19–31. [CrossRef]
Yang, Z. , Qi, B. J. , Cong, B. Q. , Liu, F. J. , and Yang, M. X. , 2015, “ Microstructure, Tensile Properties of Ti-6Al-4V by Ultra High Pulse Frequency GTAW With Low Duty Cycle,” J. Mater. Process. Technol., 216, pp. 37–47. [CrossRef]

Figures

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Fig. 1

Equipment and schematic of the weld current waveform

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Fig. 2

Sketch map of specimen preparation

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Fig. 3

Geometry of a typical axial fatigue specimen

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Fig. 4

Correlation between the number of fatigue cycles and heat input with the variation of pulse frequency

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Fig. 5

Cross-sectional optical micrographs of fusion zone (a) C-GTAW and (b) UHFP-GTAW (f = 10 kHz)

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Fig. 6

Top views of microstructure in fusion zone (a) C-GTAW and (b) UHFP-GTAW (f = 10 kHz)

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Fig. 7

Correlation between the number of fatigue cycles and grain size in fusion zone with the variation of pulse frequency (a) fatigue cycles and grain size against pulse frequency and (b) the ratio of fatigue cycles to grain size against pulse frequency

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Fig. 8

Macroscopic morphology of fatigue fracture (a) C-GTAW and (b) UHFP-GTAW (f = 30 kHz)

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Fig. 9

Microscopic morphology of crack initiation (a) C-GTAW and (b) UHFP-GTAW (f = 70 kHz)

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Fig. 10

Microscopic morphology of crack propagation (a) C-GTAW, (b) UHFP-GTAW (f = 70 kHz), (c) C-GTAW, and (d) UHFP-GTAW (f = 60 kHz)

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Fig. 11

Fatigue striations and secondary crack (a) C-GTAW and (b) UHFP-GTAW (f = 60 kHz)

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Fig. 12

Microscopic morphology of final failure (a) C-GTAW, (b) UHFP-GTAW (f = 50 kHz), (c)C-GTAW, and (d) UHFP-GTAW (f = 50 kHz)

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