Microstructure and Mechanical Properties of Vacuum Diffusion Bonded Ti2AlNb/Ti/TC4 Joint

Wang, Yifeng; Hu, Bingxu; Yan, Wei; Gui, Feng; Deng, Dean

doi:10.3390/cryst11070770

Cited by 7 publications

(5 citation statements)

References 39 publications

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“…By comparing the fractures on the Ti 2 AlNb side of the joint at 650 °C and 750 °C, it is found that the closer to the Ti 2 AlNb side, the more obvious the joint shows a ductile feature, as shown in Figure 9 b and Figure 10 b. The fracture morphology exhibits both cleavage and ductile characteristics, which is one of the typical characteristics of the interface between titanium alloy and Ti 2 AlNb alloy [ 41 ], and one of the main features in the fracture morphology of the Ti 2 AlNb tensile properties [ 42 ].…”

Section: Resultsmentioning

confidence: 99%

The Relationship between Microstructure and Fracture Behavior of TiAl/Ti2AlNb SPDB Joint with High Temperature Titanium Alloy Interlayers

et al. 2022

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In this paper, spark plasma diffusion bonding technology was employed to join TiAl and Ti2AlNb with high temperature titanium alloy interlayer at 950 °C/10kN/60 min, then following furnace cooling at cooling rate up to 100 °C/min. After welding, the joint was aging heat-treated at 800 °C for 24 h. The microstructure and the elements diffusion of the TiAl/Ti2AlNb joint was analyzed by field emission scanning electron microscopy (FESEM) with EDS. Moreover, the tensile properties of the joint were tested at room temperature, 650 °C, and 750 °C. The results show that the spark plasma diffusion bonding formed a high quality TiAl/Ti2AlNb joint without microcracks or microvoids, while also effectively protecting the base metal. Significant differences in the microstructure of the joint appeared from TiAl side to Ti2AlNb side: TiAl BM (Base Metal) → DP(Duplex) and NG (Near-Gamma) → α2-phase matrix with needle-like α-phase → bulk α2-phase → needle-like α-phase → metastable β-phase → Ti2AlNb BM. After heat treatment at 800 °C for 24 h, the microstructure of the TiAl side and the interlayer region did not change, but the density and size of the needle-like α-phase in region 3 increased slightly. The microstructure of Ti2AlNb near the weld changed obviously, and a large number of fine O phases are precipitated from the metastable β phase matrix after heat treatment. Except for the Ti2AlN near-interface region, the effect of heat treatment on the microstructure of the joint is not significant. The microhardness of the joint is in the shape of a mountain peak. The maximum microhardness at the interface is above 500 HV, and it is significantly reduced to 400 HV after heat treatment. The fracture of the joint occurred at the interface at room temperature, 650 °C, and 750 °C. with the tensile strength 450 MPa, 540 MPa, and 471 Mpa, respectively, and mainly showing brittle fracture.

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Section: Resultsmentioning

confidence: 99%

The Relationship between Microstructure and Fracture Behavior of TiAl/Ti2AlNb SPDB Joint with High Temperature Titanium Alloy Interlayers

et al. 2022

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“…The research on fatigue properties of vacuum-brazed titanium alloys is relatively limited. In addition, the focus of research on vacuum-brazed titanium alloys is usually on heterogeneous welding, new brazing material properties [9], or the element effects on microstructures [10]. There is very little research on the fatigue crack growth characteristics and life prediction of TC4 after vacuum brazing.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Fatigue Crack Growth in Vacuum-Brazed Titanium Alloy

Huang,

Hwang,

Huang

2023

Metals

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The assessment of fatigue is a crucial concern in welded components and structures. This study investigates the fatigue properties and models for predicting fatigue crack growth in Ti-6Al-4V titanium alloy when processed by vacuum brazing with TiCuNi filler. Fatigue properties and the impact of the stress ratio were determined through constant amplitude fatigue tests. By utilizing the results obtained from variable amplitude fatigue tests, various prediction models for fatigue crack growth were examined: modifications for load interaction, residual stress, and crack closure. The results indicate that the microstructures in the brazed zone consist of numerous fine, elongated needle-like Widmanstätten structures. In terms of cycle counting methods, the rainflow method outperforms the simple-range method. In the stable crack growth rate region, fatigue crack growth rate increases with the rise in stress ratio in a manner similar to high-strength steels. The Paris model without any modification obtains good predictions. For models modified with crack closure, the Elber model yields slightly better prediction results than the Schijve model. Among fatigue crack growth prediction models, the Willenborg model with residual stress modification produces the best results. Fracture surfaces within fatigued specimens’ brazed zones exhibit ductile failure characteristics, where fatigue striations and secondary cracks were observed.

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“…In recent years, there have been several attempts to fabricate Ti 2 AlNb/Ti-6Al-4V bimetallic joints using various techniques. Vacuum diffusion bonding using a Ti interlayer allowed for the achievement of sufficient joint strength [ 17 ]; however, this method imposes considerable limitations in terms of component geometrical complexity. The laser metal deposition AM process using TA15 and Ti 2 AlNb alloy powders was used to prepare bimetallic samples [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Interface Characterization of Bimetallic Ti-6Al-4V/Ti2AlNb Structures Prepared by Selective Laser Melting

2022

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Additive Manufacturing (AM) of multimaterial components is a promising way of fabricating parts with improved functional properties. It allows for the combination of materials with different properties into a single component. The Ti2AlNb-based intermetallic alloy provides high temperature strength, while the Ti-6Al-4V (Ti64) alloy has good fracture toughness, ductility, and a relatively low cost. A combination of these alloys into a single component can be used to produce advanced multimaterial parts. In this work, Ti2AlNb/Ti-6Al-4V bimetallic structures were fabricated from pre-alloyed powders using the Selective Laser Melting (SLM) process. The effects of high-temperature substrate preheating, post-processing by annealing, and hot isostatic pressing on defect formation, the microstructural evolution of the interface area, and the mechanical properties of the bimetallic samples were investigated. High-temperature substrate preheating during the SLM process was necessary to prevent reheat cracking of the Ti2AlNb part, while annealing and hot isostatic pressing post-processing improved the chemical and microstructural homogeneity of the transition zone and enhanced the tensile properties of the bimetallic structure.

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Microstructure and Mechanical Properties of Vacuum Diffusion Bonded Ti2AlNb/Ti/TC4 Joint

Cited by 7 publications

References 39 publications

The Relationship between Microstructure and Fracture Behavior of TiAl/Ti2AlNb SPDB Joint with High Temperature Titanium Alloy Interlayers

The Relationship between Microstructure and Fracture Behavior of TiAl/Ti2AlNb SPDB Joint with High Temperature Titanium Alloy Interlayers

Prediction of Fatigue Crack Growth in Vacuum-Brazed Titanium Alloy

Interface Characterization of Bimetallic Ti-6Al-4V/Ti2AlNb Structures Prepared by Selective Laser Melting

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