Interface microstructural control by probe length adjustment in friction stir welding of titanium and steel lap joint

Gao, Y.; Nakata, Kohei; Nagatsuka, Kimiaki; Liu, Fengchao; Liao, Jinsun

doi:10.1016/j.matdes.2014.08.063

Cited by 55 publications

(19 citation statements)

References 21 publications

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“…In case the thickness of Nb foil is 0.22 mm, compared with the kovar alloy side, the fusion zone of the titanium alloy side is narrower, existed with some unmelted interlayer areas, as shown in Figure 3(a). Previously, Gao et al [10] welded titanium to a steel by using friction stir welding and found the existence of FeTi and Fe 2 Ti. It was reported that Fe-Ti-Cu IMCs formed in the weld zone when electron beam welding of a titanium alloy and a stainless steel was carried out with a Cu interlayer [23].…”

Section: Resultsmentioning

confidence: 99%

“…Kundu et al [9] showed that when titanium was diffusion bonded to a 17-4PH stainless steel, FeTi and Fe 2 Ti were produced. If friction stir welding of titanium and steel was carried out in an overlapped manner, the interface exhibited a layershaped structure containing FeTi and Fe 2 Ti, which were unfavorable to the quality of welded joints [10]. Satoh et al [4] found that coarse intermetallic TiFe dendrites formed in the main fusion zone, which was adverse to properties of welded joints.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Mechanical Properties of Electron Beam‐Welded Joints of Titanium TC4 (Ti‐6Al‐4V) and Kovar (Fe‐29Ni‐17Co) Alloys with Cu/Nb Multi‐Interlayer

Fang

Jiang

et al. 2018

Advances in Materials Science and Engineering

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Electron beam welding of a titanium alloy (Ti-6Al-4V) and a kovar alloy (Fe-29Ni-17Co) was performed by using a Cu/Nb multi-interlayer between them. Microstructure and composition of welded joints were analyzed by means of optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Mechanical properties of welded joints were evaluated by microhardness and tensile strength tests. Results indicated that in case of 0.22 mm thickness of Nb foil, microstructure of the titanium alloy side was mainly composed of Ti solid solution and some intermetallic compounds such as FeTi and CuTi2, whereas in case of 0.40 mm thickness of Nb foil, the appearance of weld was more uniform and hardness of the weld zone decreased sharply. However, tensile strength of welded joints was increased from 88.1 MPa for the 0.22 mm Nb foil to 150 MPa for the 0.40 mm Nb foil. It was found that thicker Nb foil could inhibit diffusion of Fe atoms towards the titanium alloy side, thus promoting the formation of Ti solid solution and a small amount of CuTi2 and eliminating FeTi. In addition, in both cases, Cu0.5Fe0.5Ti was found in the fusion zone of the titanium alloy side, which had an adverse effect on mechanical properties of welded joints.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Electron Beam‐Welded Joints of Titanium TC4 (Ti‐6Al‐4V) and Kovar (Fe‐29Ni‐17Co) Alloys with Cu/Nb Multi‐Interlayer

Fang

Jiang

et al. 2018

Advances in Materials Science and Engineering

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“…High thermal conductivity and a lack of strengthening precipitates results in a very wide "die" (or no "die"). Thus, when FSW pure Al the weld area is significantly wider than the diameter of the probe [20,21,43,44]. The enlarged gap at the AS between the probe and the only slightly stronger base material allows material in the MFZ to rotate more than once around the tool.…”

Section: Influence Of Material/fsw Process On Materials Flowmentioning

confidence: 99%

In-situ material flow pattern around probe during friction stir welding of austenitic stainless steel

Liu

Nelson

2016

Materials & Design

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The probe route as well as the material flow around the keyhole during weld termination were tracked and used to determine the probe position just prior to weld termination. This approach enables analysis of in-situ microstructure distribution and the nature of material flow during friction stir welding (FSW). A FSW flow model was established. During steady state FSW, the material at the advancing side (AS) recrystallized rapidly when it was swept by the hot rotating probe. The recrystallized grains were driven to rotate around the probe along the tool rotation direction, forming the material flow zone (MFZ). As the base material approached the probe, it was compressed initially, forming a compression zone (CPZ) mainly consisted of coarse deformed grains. When the coarse deformed grain in CPZ collided with the hot material in the MFZ, it recrystallized and added into the MFZ, thickening the MFZ ahead of the probe. During FSW, the material intersecting the path of probe was displaced to rotate around the probe and then deposited behind the probe at roughly the same transverse position as its initial position.

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“…Chen et al [4] showed that if CP Ti and 304 stainless steel were bonded by laser welding technology, 2 of 14 some brittle IMCs (Fe 2 Ti and FeTi) easily formed in the weld metal. Similarly, Gao et al [5] joined titanium and 17-4PH stainless steel by friction stir welding. It was found that a layer-shaped structure formed at the interface, which was composed of FeTi and Fe 2 Ti.…”

Section: Introductionmentioning

confidence: 99%

Influence of Welding Speed on the Microstructure and Mechanical Properties of Electron Beam-Welded Joints of TC4 and 4J29 Sheets using Cu/Nb Multi-Interlayers

Wang

Fang

et al. 2018

Metals

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Dissimilar metal joining between titanium and kovar alloys was conducted using electron beam welding. Metallurgical bonding of titanium alloys and kovar alloys was achieved by using a Cu/Nb multi-interlayer. The effects of welding speed on weld appearance, microstructure and mechanical properties of welded joints were investigated. The microstructure of welded joints was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). The mechanical properties of welded joints were investigated by tensile strength and micro-hardness tests. The results showed that welding speed had great effects on the weld appearance, microstructure, and mechanical properties of electron beam-welded joints. With an increase of welding speed, at the titanium alloy side, the amount of (Nb,Ti) solid solution was increased, while the formation of brittle FeTi was effectively suppressed. At the kovar alloy side, microstructure was mainly composed of soft Cu solid solution and some α-Fe + γ phases. In addition, higher welding speeds within a certain range was beneficial for eliminating the formation of cracks, and inhibiting the embrittlement of welded joints. Therefore, the tensile strength of welded joints was increased to about 120 MPa for a welding speed of 10 mm/s. Furthermore, the bonding mechanism of TC4/Nb/Cu/4J29 dissimilar welded joints had been investigated and detailed.

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Interface microstructural control by probe length adjustment in friction stir welding of titanium and steel lap joint

Cited by 55 publications

References 21 publications

Microstructure and Mechanical Properties of Electron Beam‐Welded Joints of Titanium TC4 (Ti‐6Al‐4V) and Kovar (Fe‐29Ni‐17Co) Alloys with Cu/Nb Multi‐Interlayer

Microstructure and Mechanical Properties of Electron Beam‐Welded Joints of Titanium TC4 (Ti‐6Al‐4V) and Kovar (Fe‐29Ni‐17Co) Alloys with Cu/Nb Multi‐Interlayer

In-situ material flow pattern around probe during friction stir welding of austenitic stainless steel

Influence of Welding Speed on the Microstructure and Mechanical Properties of Electron Beam-Welded Joints of TC4 and 4J29 Sheets using Cu/Nb Multi-Interlayers

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