Influence of Annealing on the Properties of Explosively Welded Titanium Grade 1—AW7075 Aluminum Alloy Bimetals (original) (raw)
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Journal of Materials Engineering and Performance, 2019
Explosive welding of AW5754 aluminum alloy to AZ31B magnesium alloy was performed. AW5754 was proposed as a flyer plate. A parallel setup was used during explosive welding. The annealing of AW5754/ AZ31B composite plate at 250, 300 and 350°C for 2, 3, 4 and 5 h was performed after explosive welding. Bimetals were characterized by regular wavy interface. Annealing resulted in the creation of intermetallic compounds (IMCs). The increase in the thickness of IMC interfacial layer was observed with increasing of annealing temperature and time. IMC layer of highest thickness was recorded after annealing at 350°C for 5 h and averaged 67 lm. EDS analysis showed that the interfacial layer close to AW5754 alloy was formed by Al 3 Mg 2 IMC, and interfacial layer adjacent to the AZ31B alloy consisted of Mg 17 Al 12 IMC. Bright particles were spread at the AW5754-Al 3 Mg 2 IMC interface. Rise in the microhardness at the interface of produced bimetal was associated with work hardening. Microhardness values increased to 218 HV0.025 after annealing process due to IMCs present at the interface. Decrease in microhardness in locations close to the IMC interfacial layer was found after heat treatment due to recrystallization. The bimetal tensile strength reached 120 MPa. The annealing resulted in decrease in the bimetal tensile strength.
Journal of Materials Engineering and Performance, 2016
The manuscript presents a close examination of the titanium and aluminum platters manufactured by explosive welding method. In particular, the microstructure changes of the Al/Ti wavy shape interface after annealing at 773 and 903 K were studied. Three stable TiAl 3 , TiAl, and Ti 3 Al and a metastable TiAl 2 intermetallic phases have been formed in the state directly after explosive welding. The orientation map and TEM images obtained after explosive welding process showed very fine grains of aluminum mixed with intermetallics in the interface region between the peninsulas or islands. After annealing for 100 h the TiAl 3 continuous layer was obtained; however, the layer achieved at 903 K was much wider than that obtained at 773 K. An examination of the growth kinetics at 903 K revealed that incubation time was less than 5 min. After this period, the growth was solely governed by chemical reaction.
Metallurgical and Materials Transactions A, 2017
The microstructure and phase composition of Al/Ti/Al interfaces with respect to their localization were investigated. An aluminum-flyer plate exhibited finer grains located close to the upper interface than those present within the aluminum-base plate. The same tendency, but with a higher number of twins, was observed for titanium. Good quality bonding with a wavy shape and four intermetallic phases, namely, TiAl 3 , TiAl, TiAl 2 , and Ti 3 Al, was only obtained at the interface closer to the explosive material. The other interface was planar with three intermetallic compounds, excluding the metastable TiAl 2 phase. As a result of a 100-hour annealing at 903 K (630°C), an Al/TiAl 3 /Ti/TiAl 3 /Al sandwich was manufactured, formed with single crystalline Al layers. A substantial difference between the intermetallic layer thicknesses was measured, with 235.3 and 167.4 lm obtained for the layers corresponding to the upper and lower interfaces, respectively. An examination by transmission electron microscopy of a thin foil taken from the interface area after a 1-hour annealing at 825 K (552°C) showed a mixture of randomly located TiAl 3 grains within the aluminum. Finally, the hardness results were correlated with the microstructural changes across the samples.
Metals, 2019
The aim of this paper is to study the microstructure and mechanical properties of the Ti6Al4V/Al-1060 plate by explosive welding before and after heat treatment. The welded interface is smooth and straight without any jet trapping. The disturbances near the interface, circular and random pores of Al-1060, and beta phase grains of Ti6Al4V have been observed by Scanning electron microscopy (SEM). Heat treatment reduces pores significantly and generates a titanium-island-like morphology. Energy dispersive spectroscopy (EDS) analysis results show that the maximum portion of the interfacial zone existed in the aluminium side, which is composed of three intermetallic phases: TiAl, TiAl2 and TiAl3. Heat treatment resulted in the enlargement of the interfacial zone and conversion of intermentallic phases. Tensile test, shear test, bending test and hardness test were performed to examine the mechanical properties including welding joint qualities. The results of mechanical tests show that th...
Metallurgical and Materials Transactions A, 2014
Metallic-intermetallic laminate composites are promising materials for many applications, namely, in the aerospace industry. Ti/TiAl 3 laminates are one of the interesting laminate composites, which are mostly used in aerospace applications. In this work, commercially pure aluminum and titanium sheets were explosively joined. The multilayer samples were annealed between 1 and 260 hours at 903 K (630°C) in ambient atmosphere, and the formation and growth of the intermetallic compound at the Ti/Al interface were monitored. Microstructural investigations were carried out using optical and scanning electron microscopes equipped with energy-dispersive spectroscopy and the X-ray diffraction technique. The microhardness profile of the layers was also determined. The thickness and type of Al-Ti intermetallics were determined. It was found that the only intermetallic phase observed in the interfaces was TiAl 3 . It was also shown that two mechanisms for TiAl 3 growth exist: reaction and diffusion controlled. The growth exponent was equal to 0.94 for the reaction-controlled mechanism (first step) and 0.31 for the diffusion-controlled mechanism (second step). These values were in good agreement with theoretical values (1 and 0.5 for the first and second steps, respectively). Based on the results of this research, a kinetic model for the formation and growth of TiAl 3 intermetallic phase was proposed.
Archives of Civil and Mechanical Engineering
The processes of rolling and annealing of explosively welded multi-layered plates significantly affect the functional properties of the composite. In current research, fifteen-layered composite plates were fabricated using a single-shot explosive welding technique. The composites were then rolled up to 72% to reduce layer thickness, followed by annealing at 625 °C for varying times up to 100 h. Microstructure evolution and chemical composition changes were investigated using scanning electron microscopy equipped with energy-dispersive spectroscopy. The mechanical properties of the composite were evaluated by tensile testing, while the strengths of individual layers near the interface were evaluated by micro-hardness measurements. After explosive welding, the wavy interfaces were always formed between the top layers of the composite and the wave parameters decreasing as the bottom layers approach. Due to the rolling process, the thickness of Ti and Al layers decreases, and the wavine...
2020
In this research, the effect of heat treatment on the microstructure and mechanical properties of intermetallic compounds of welding joint interface of three explosive layers of 5083 and 1050 aluminum as flying and intermediary plates and AISI steel sheet as the base plate has been discussed and investigated. To show the effect of temperature and time, the welded samples with stand-off distance of 6, 8, and 10mm and the explosive load of 2.41 were placed on heat treatment in the constant temperature of 315°C and 450°C within a furnace protected by Argon gas for six hours. Laboratory investigations have been conducted by the use of photomicroscope, scanning electronic microscopy, and microhardness assessing tests. Metal compounds of the interface were specified by the use of EDS analysis. In the considered samples before heat treatments, the interface of the joint has been converted from the short wavy state into the vertical wavy state by the increase of stand-off distance from 6 mm...
AlMg6 to Titanium and AlMg6 to Stainless Steel Weld Interface Properties after Explosive Welding
Metals
This paper studies the weld interface microstructure and mechanical properties of AlMg6-stainless steel and AlMg6-titanium bimetals produced using explosive welding. The microhardness (HV), tear strength, and microstructure of the weld seams were evaluated. The interface of the weld zones had a flat profile. No structural disturbances or heterogeneity in the AlMg6-titanium weld interface were observed. On the other hand, the bimetal AlMg6-stainless steel had extensive zones of cast inclusions in the 10–30 µm range. SEM/energy-dispersive X-ray spectroscopy (EDS) analysis showed the presence of a hard and brittle intermetallic compound of Al and FeAl3 (with 770–800 HV). The microhardness of the AlMg6-titanium bimetal grew higher closer to the weld interface and reached 207 HV (for AlMg6) and 340 HV (for titanium). Both bimetals had average tear strength below 100 MPa. However, the tear strength of some specimens reached 186 and 154 MPa for AlMg6-titanium and AlMg6-stainless steel, res...
Interfacial Microstructure and Mechanical Properties of Explosively Welded Mg/Al Alloy Plates
Journal of Materials Engineering and Performance, 2022
The interfacial microstructure and hardness of cladding plates produced by explosive welding between magnesium alloys having different aluminum concentrations and A6005C aluminum alloy were investigated. Further, measurements of residual stress at the interface of cladding plates were performed. In all cladding plates, the bonding interface had a wavy shape. Adiabatic shear bands were formed at the interface on the magnesium alloy side and deformation twins appeared at the interface due to the impact of explosive welding. Microstructure observation using scanning transmission electron microscope revealed that a thin interlayer was formed at the interface in all cladding plates. The thickness of the interlayer increased with an increase in aluminum concentration in the magnesium alloy, while the thickness was 1 μm or less. In the cross-section of the cladding plate, aluminum alloy showed a relatively higher Vickers hardness value compared with the magnesium alloy, and the hardness value increased when approaching the interface. However, nanoindentation tests revealed no increase in hardness was observed at the interface. Measurements of the residual stress using synchrotron radiation x-rays at the interface of cladding plates revealed a tendency for the occurrence of tensile residual stress on the magnesium alloy side and compressive residual stress on the aluminum alloy side. This might be due to a difference in the coefficient of thermal expansion between the magnesium and aluminum alloys. Keywords aluminum, dissimilar metal joining, explosive welding, interlayer, magnesium, residual stress This article is an invited submission to the Journal of Materials Engineering and Performance selected from presentations at the symposium "Joining," belonging to the area "Processing" at the European Congress and Exhibition on Advanced Materials and Processes (EUROMAT 2021), held virtually from September 12-16, 2021, and has been expanded from the original presentation.
Journal of Composites Science
One of the ways to simultaneously increase the strength and the fracture and impact toughness of structural materials is by producing multilayered materials. In this paper we discuss the structure and properties of a seven-layer composite obtained by explosive welding of high-strength titanium alloys. The structure of the composite was characterized using light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). At the interfaces between plates, formation of waves and vortices was observed. The wave formation is discussed with respect to the kinetic energy loss. The vortices consisted of a mixture of two alloys and possessed a martensitic structure comprising α and β phases of titanium. Localized plastic deformation occurred along the interfaces during explosive welding by formation of shear bands. The most intensive shear banding occurred in the vicinity of the upper interfaces. The local hardness at the interfaces increased due to the formation of the quenched structures. The interfaces between titanium alloys positively influenced the impact toughness of the composite, which increased in comparison with that of bulk titanium alloys by a factor of 3.5. The strength characteristics of the composite remained at the same level as that of the bulk material (1100-1200 MPa). alloys can reach 1200 MPa. Heat treatment of some high-strength titanium alloys increases the UTS up to 1500 MPa . Equal channel angular pressing (ECAP) increases the UTS of CP titanium by a factor of 2.5 [3-6]. However, an important disadvantage of all these technologies is the decrease of ductility and impact toughness of the material, which negatively affects the reliability of titanium products.