Ti Filler Research Articles

High-strength WC-Co/Low carbon steel connected by Ni–Cr–Fe alloy through brazing for roller sleeves

Enhancing the bond strength between WC-Co and steel is crucial for broadening its applications. In this study, WC-Co was bonded to low-carbon steel (LCS) using a Ni–Fe–Cr alloy at 1180 °C in an argon atmosphere furnace. The WC-Co/LCS (WL) interface was characterized by XRD, SEM, and EPMA, revealing no cracks or pores and confirming robust metallurgical bonding. The bonded material's shear strength reached approximately 321–328 MPa, significantly exceeding that achieved with Ag–Cu–Zn–Cd, Cu–Zn, Cu–Ni–Al, Ag–Cu–Zn + Ni/Mn, and Ag–Cu–In–Ti filler materials in the welding process. EPMA analysis showed that Fe, Cr, and Ni from the Ni–Fe–Cr alloy diffused into the WC-Co over distances of approximately 802–815 μm, 803–817 μm, and 632–641 μm, respectively. Initially, WC decomposed at sharp corners to form W₂C, which subsequently reacted with Fe and Cr to form M₆C and M₇C₃. This methodology was also applied to producing roller sleeves for vertical mills, increasing their lifespan by 1.9 times.

Electron Beam Welding of Copper and Aluminum Alloy with Magnetron Sputtered Titanium Filler

In this work, the results from the electron beam welding of copper and Al6082T6 aluminum alloy with a titanium filler are presented. The influence of the filler on the structure and mechanical properties of the welded joint is studied in comparison with one without filler. The X-ray diffraction (XRD) method was used to obtain the phase composition of the welded joints. Scanning electron microscopy (SEM) was used for the study of the microstructure of the welds. Energy-dispersive X-ray spectroscopy (EDX) was applied to investigate the chemical composition. The mechanical properties were studied by means of microhardness measurements and tensile tests. A three-phase structure was obtained in the fusion zone consisting of an aluminum matrix, an intermetallic compound CuAl2, and pure copper. The application of Ti filler significantly decreased the amount of molten copper introduced in the molten pool and the number of intermetallic compounds (IMCs). This improved the strength of the joint; however, some quantity of IMCs was still present in the zone of fusion (FZ), which reflected the microhardness of the samples. The application of a titanium filler resulted in refining the electron beam weld’s structure. The finer structure and the reduced amount of the brittle intermetallic phases has led to an increase in the strength of the joint.

Microstructure and mechanical property of Zr-4 alloys brazed with Ag–Cu–Ti filler metal

Microstructure and mechanical property of Zr-4 alloys brazed with Ag–Cu–Ti filler metal

Modulation of Co-depleted zone and shear strength of YG18/40Cr joints by pre-plated Co layer on YG18 surface

The multi-layer composite filler metal (YG18 surface pre-plated with Co layer + Ag–Cu–In–Ti filler metal) was designed in this study. The mechanism of modulation of Co-depleted zone and shear strength of joints by Co plating was elucidated. A more significant Co-rich layer existed around the WC particles, meanwhile, the presence of plastical Ag–Cu–In ternary eutectic between the TiCo layer and the YG18/TiC layer relieved the joint stress and ensured that no cracks were generated in the TiCo layer. Under the condition that the width of the Co-depleted zone was smaller (less than 3 μm), the presence of the dispersed Ti2Cu particles surrounded by the plastic phases ternary eutectic and Cu [s, s] in the filler layer was superior in terms of preventing crack propagation and absorbing the stress concentration. The best modulation of the filler layer microstructure and the Co-depleted zone was achieved when the pre-plated Co layer was around 2.5 μm. The Co-depleted zone was reduced by 50%, and the shear strength of joints was increased by 49% to 291 MPa. The results of the study provide a new way to design new multilayer composite filler metal.

Laser welding of molybdenum and stainless steel with Cu[sbnd]Ti filler metal

Brittle MoFe intermetallic compounds (IMCs) are usually fatal for the joining of Mo and steel. In the present work, Ni-free joining of Mo and stainless steel was successfully achieved by laser welding with CuTi filler metal. The entry of Mo element into the weld seam and the formation of MoFe IMCs was significantly suppressed. TiFe, TiFe2, Ti5Cr8Fe16, and Cu-Ti-Fe phases were found inside the weld and near the interface. The IMCs were separated by Cu matrix and no continuous layered IMCs were found. The brittle fracture characteristics of TiFe IMCs and plastic deformation of the Cu matrix was found on the fracture surface in the weld.

Interfacial microstructure and mechanical properties of Si3N4/Invar joints using Ag–Cu–In–Ti with Cu foil as an interlayer

Abstract Si3N4 and Invar alloy brazed joints were achieved using two types of Ag-based interlayers: a Ag–Cu–In–Ti foil and a Ag–Cu–In–Ti/Cu/Ag–Cu multi-interlayer. The results showed that when only using a single Ag–Cu–In–Ti filler, the wave-shaped Fe2Ti + Ni3Ti intermetallic compounds are concentrated in the middle of the brazing seam. When adding Cu as the interlayer, the dissolution of the Cu interlayer formed a large number of Cu(s,s) blocks of different sizes in the brazing seam, which hindered the concentrated distribution of Fe2Ti + Ni3Ti intermetallic compounds in the brazing seam. As a result, Fe2Ti and Ni3Ti were dispersedly distributed in the brazing seam, increasing the shear strength of the brazed joint. The shear strength of brazed joints was increased by 82 % compared to joints brazed with a single Ag–Cu–In–Ti filler when the Cu interlayer was added.

Interfacial microstructure and mechanical properties of joints between ZrO2 ceramic and 316 stainless steel brazed using Ag–Cu–In–Ti filler

An active Ag-based filler containing the melting point depressant of In was used for brazing ZrO2 ceramic with 316 stainless steel (SS) at relatively low brazing temperatures. The brazing feasibility to obtain a robust joint was investigated via changing brazing temperatures from 740 to 820 °C with a holding time of 10–30 min. The typical microstructure of the ZrO2/316SS joint was ZrO2/TiO/Cu2Ti4O + Ag(s, s) + Cu(s, s)/Ag(s, s) + Cu(s, s) + Cu(Ti, In) + FeTi + Cu(Ti, Fe)/316SS. The type of reaction products primarily depended on the brazing temperature, and the TiO phase appeared only at 780 and 800 °C, while the FeTi formed at temperatures higher than 760 °C. Meanwhile, the blocky Cu(Ti, In) and Cu(Ti, Fe) compounds were gradually replaced by the FeTi phase due to the enhanced affinity of Ti and Fe in the liquid alloy. The maximum shear strength reached 308 MPa at 780°C-20 min, and the typical fracture occurred at the Ag-based solid solution and reaction bilayer bordering the ZrO2 ceramic. Notably, a shear strength of above 270 MPa was obtained at wide temperatures from 760 to 820 °C, higher than ZrO2/SS brazed joints using other Ag-based fillers.

Microstructure and Mechanical Properties of the Joint between Si3N4 and Mo Brazed by Near‐Eutectic Ag–Cu–In–Ti Filler Alloy

The joining of Si3N4 and Mo using Ag–Cu–In–Ti active filler alloy with the brazing temperature ranging from 720 to 860 °C for 10 min is investigated in this article. The correlation between the joint strength and the microstructures of the brazed joints is discussed. In the results, it is shown that the activity of Ti is different at different temperatures, and thus the degree of diffusion of Ti to the interface is different. The activity of Ti gradually increases as the brazing temperature increases, and more Ti atoms diffuse into both sides of the base materials, resulting in a progressively thicker TiN + Ti5Si3 reaction layer on the Si3N4 ceramic side. Between 720 and 860 °C, the shear strength of the joint first increases and then decreases with brazing temperature. The maximum shear strength (223 MPa) is obtained at 830 °C.

Microstructure and properties of a YG18/40Cr joint vacuum–brazed by Cu–Sn–Ti filler metal

In this study, dissimilar YG18/40Cr joints were prepared using a Cu–Sn–Ti filled metal by a vacuum brazing process, and the microstructural evolution and bonding mechanism of the YG18/Cu–Sn–Ti/40Cr joints were studied. By adjusting the brazing parameters, the formation process of interface structure, the joint structure and matrix internal structure, and the changes in the joint microstructure and properties under different parameters were systematically analyzed. A TiC reaction layer was formed at the interface on both sides of the joint. The brazing performance can be improved by the formation of a reasonable size reaction layer. A TiC–WC cemented carbide was formed near the middle layer inside YG18, and this tenon–and–tenon structure improved the bonding between the YG18 side and the filler alloy. The connector structure was YG18/TiC/CoTi + Co2SnTi/Cu [s, s]/eutectic structure (Cu [s, s] + Cu Sn3Ti5)/CuSn3Ti5/TiC/40Cr, and its eutectic structure changed as the parameters changed. The maximum average shear strength of the YG18/40Cr joint brazed at 940 °C for 5 min reached 216 MPa, which was ≈25% higher than the joint shear strength of the pure copper used in a previous study. The fracture morphology of the joint showed a large number of fossae and tear edges, indicating ductile fracture.

Self-joining of K9 glass using Sn0.3Ag0.7Cu-Ti filler metal and its joint properties

Solving the problem of poor spreading ability of metal filler on glass is important in studying the bonding of glass. In this work we achieved the self-joining of K9 glass using Sn0.3Ag0.7Cu (SAC)-Ti filler. The addition of Ti (1, 2, 3, 4, 6, and 8 wt%) was shown to effectively impact the microstructure and mechanical properties of the brazing joints. A dense K9/SAC-x%Ti/K9 joint can be obtained through the reaction of Ti and SiO2, which formed TiO2 and TiSi at the brazing temperature of 630–690 ℃ for 10 min. Meanwhile, the brazing seam of K9/SAC-x%Ti/K9 joints also possessed a Sn matrix with Ti2Sn3 phases. According to the shear test, the brazed joint with 3 % Ti content could reach a maximum value of 19.3 MPa at 650 °C. The introduction of Ti effectively modified the wettability of SAC filler on K9 glass and provided a new brazing method for low-softening point glass.

Joining SiCf/SiC composites to Al0.3CoCrFeNi high-entropy alloys with a Cu–Ti filler alloy: Interfacial reactions, high-entropy effects, and mechanical properties

SiCf/SiC composite and Al0.3CoCrFeNi high-entropy alloys, which are valued as promising candidate materials for nuclear reactors, were successfully brazed together, achieving the maximum strength of 59 MPa at room temperature and 49 MPa at 700 °C. The high-entropy effect and its deviation caused by the unavoidable elemental segregation in brazing were uniquely considered. It was proved that the Si from ceramics or the Ti from fillers usually caused segregation by increasing the enthalpy, which raised doubts whether high-entropy alloys could play an expected role in brazing some specific materials. The microstructural evolution, mechanical properties, and fracture modes of the joints were identified in detail. The erosion of metal atoms to the SiCf/SiC composite was observed from the directions perpendicular and parallel to the interface, which presented a fiber-orientation-dependent manner.

Induction brazing of Al2O3 ceramic and 316L stainless steel with Sn–Ti filler alloy

An induction brazing method for joining Al2O3 ceramic to 316L stainless steel (SS) was developed in this study. The Sn–Ti alloy was rapidly melted by induction heating, which enabled the active element Ti to react with O in Al2O3. Consequently, a metallurgical bonding formed between and Al2O3 and 316L SS. The microstructure of the joint was mainly composed of Fe2SnTi layer, FeSn2, Ti6Sn5 particles and TiO layer. The maximum shear strength of 20 MPa was obtained at 260 A/140 s. The induction heating exhibited a higher heating rate compared to traditional resistance heating, as evidenced by the brazing process with only approximately 140 s. The proof-of-concept study on the induction brazing of Al2O3 ceramic to 316L SS with high efficiency provides insights in the further development of ceramic/metal joining.

Brazing YAG ceramic to Kovar alloy with Ag–Cu–Ti filler alloy: Wettability, microstructure and mechanical properties

YAG ceramic was brazed to Kovar alloy under a high vacuum of 6–8 × 10−4 Pa. A good contact angle (θeq = 10.7°) was obtained by wetting AgCuTi filler metal on the YAG ceramic substrate, and the associated interfacial microstructure was characterized. The microstructure of the achieved YAG/Kovar joints brazed by AgCuTi filler was characterized by SEM, TEM and XRD, which was found to be YAG/Y2O3/(Fe, Ni)Ti/Ag(s, s) + Cu(s, s)/Fe2Ti + Ni3Ti/Fe2Ti/Kovar. The effects of different brazing temperatures on the joint structure were investigated. The thickness of the (Fe, Ni)Ti reaction layer increases, and the banded structure formed by Fe2Ti and Ni3Ti intermetallic compounds (IMCs) widens with increasing brazing temperature. Nanoindentation and shear tests were used to characterized the mechanical properties of the joints. As the brazing temperature increased, the shear strength of the joints first increased and then decreased. A joint with an optimal shear strength of 51.3 MPa was obtained at 870 °C for 10 min. The nanoindentation test reveals the obvious differences in mechanical properties between phases: (Fe,Ni)Ti phase has higher Young's modulus and hardness than Fe2Ti–Ni3Ti phase and Ag–Cu eutectic.

Interfacial microstructure and mechanical properties of WC–Co/40Cr joints brazed at low–temperature with Ag–Cu–Ti + Sn novel filler

It is crucial to design a novel active filler metal for brazing WC–Co cemented carbide–steel joints at low temperatures. In this study, we designed a low-melting-point multi-component active filler metal (Ag–Cu–Sn–Ti) based on Ag–Cu–Ti filler metal to achieve perfect combination of WC–Co/40Cr steel joints. The interfacial microstructure of the WC–Co/40Cr steel joint was comprehensively characterized, and the joint-bonding mechanism, mechanical properties, and fracture behavior after brazing at 700–780 °C were systematically analyzed. On both sides of the filler metal, WC and α-Fe combined with the TiC layer, enhancing the bonding of the filler metal to base materials. The typical structure of the joint is WC–Co/TiC layer/Co2SnTi + Cu–doped Cu81Sn22 + Ag [s, s] + Ti–Cu granules/TiC layer/40Cr. The maximum shear strength of 241 MPa was obtained when the joint was brazed at 740 °C for 10 min, which is approximately 50% higher than those of previous low-temperature vacuum-brazed WC–Co/steel joints. The main factors leading to premature failure of joint include the distribution of phases in filler metal layer and defects of WC–Co caused by Co diffusion.

Laser welding of ZrO2 ceramic and 304 stainless steel with Ag–Cu–Ti filler

In this paper, the joining of ZrO2 ceramic and 304 stainless steel (SS) was realised by laser offset welding with AgCuTi filler metal. The heat was transferred from the molten pool to the solder through the unmelted SS. AgCuTi would diffuse to form eutectic products with low melting point, forming metallurgical reaction zone. The unmelted SS was retained by laser migration to avoid the mixing of molten solder and molten pool, which reduced the content of brittle phase in the joint. In addition, the crack-free welded joint with a tensile strength of 71 MPa was obtained. The elemental diffusion model was used to simulate the interfacial microstructure changes, and the microstructure was reasonably predicted by changing the welding parameters.

Microstructure and properties of WC–Co cemented carbide/40Cr steel joints brazed at low–temperature with Ag–Cu–In–Ti filler alloy

WC–Co cemented carbide/steel brazed at low–temperature is of significant scientific and technical interest. In this study, the interface microstructure between the filler alloy and WC–Co and 40Cr steel, the formation process of the joint microstructure, and the effect of brazing temperature on the microstructure and properties of joints were systematically studied. The filler alloy was bonded by forming a TiC reaction layer with WC–Co and 40Cr steel, which enhanced the retention of the filler layer on the joint. The microstructure of the joint was a WC–Co/TiC reaction layer/TiCo reaction layer/Cu2InTi + eutectic structure (Ag [s, s] + Ag–doped Cu7In3 + Cu4In) + Cu [s, s]/TiC reaction layer/40Cr steel. Moreover, the maximum average shear strength of the joint (brazed at 740 °C) reached 258 MPa, which is approximately 60% higher than those reported in the literature. The fracture behavior of the joint was mainly affected by the distribution of the Cu2InTi intermetallic compounds in the filler layer and the diffusion of Co from the cemented carbide.

Microstructures and mechanical properties of YG18 cemented carbide/40Cr steel joints vacuum brazed using Ag–Cu–Ti filler metal

YG18 cemented carbide and 40Cr steel were brazed using Ag–Cu–Ti filler metal under vacuum, and the microstructural evolution of the YG18/Ag–Cu–Ti filler metal/40Cr steel brazed-joint interface was investigated to determine how brazing temperature affected the brazed-joint microstructure, bonding strength, and fracture behavior. At the YG18 cemented carbide/filler metal interface, Ti atoms in the filler metal and C atoms in the YG18 cemented carbide formed a continuous TiC layer, reducing the difference in thermal expansion coefficients between the YG18 cemented carbide and filler metal. At the 40Cr steel/filler metal interface, Ti atoms in the filler metal and C atoms in the 40Cr steel formed a continuous TiC layer, preventing the diffusion of Fe atoms to the cemented carbide side and formation of a hard, brittle phase. YG18 cemented carbide/TiC/Cu2Ti/Ag–Cu eutectic + TiCu granules/TiC/40Cr steel-brazed joints were obtained. With increasing brazing temperature from 860 to 920 °C, the bonding strength of the YG18 cemented carbide/40Cr steel joint initially increased and then decreased. The joint brazed at 900 °C for 10 min failed in the middle of the brazing seam, and its average bonding strength was 235 MPa.

Improvement for electrical conductivity of Ti3SiC2/Cu joint brazed with a novel Sn6Ag7Ni4Co2Ti low-melting high entropy alloy filler

Reducing the interfacial electrical resistance of Ti3SiC2/Cu joint has significant value to promote its application in the field of electrical contact. In the study, a novel Sn6Ag7Ni4Co2Ti low-melting high entropy alloy (HEA) was designed and fabricated, and a sound Ti3SiC2/Cu brazed joint was obtained using above filler. The interface of Ti3SiC2/Cu joint brazed with Sn6Ag7Ni4Co2Ti filler is mainly composed of Ag(s,s), Cu(s,s) and a few (Ni, Co)2Si. Compared with Ti3SiC2/Cu joint brazed with Ag-26.7Cu-4.5Ti filler, the electrical resistance of the joint brazed with Sn6Ag7Ni4Co2Ti filler is lower at all test temperatures, which is reduced by up to 15.99% when the test temperature is 300 °C.

Analysis of the Reaction Layer Formed during Sapphire–Sapphire Brazing Using a Ag–Cu–Ti Filler Metal for Gas-Pressure Sensors

Analysis of the Reaction Layer Formed during Sapphire–Sapphire Brazing Using a Ag–Cu–Ti Filler Metal for Gas-Pressure Sensors

Influence of SiC nanowires on the microstructures and properties of Ag–Cu–Ti filler metals and brazed joints

Ag–26.7Cu–4.5Ti filler metals with different contents of SiC nanowires were prepared to analyze the effect of SiC nanowires on the microstructures, melting temperature, wettability, shear strength and fracture morphology of brazed joints. The results indicate that a small amount of SiC nanowires ([Formula: see text]0.1%) can refine the matrix microstructure and reduce the Cu–Ti intermetallic compounds, which can induce the increase of shear strength of brazed joints with 46.7% maximum amplitude, the ductile pattern is the main fracture mode for Ag–Cu–Ti–1.0 SiC brazed joints. Moreover, the SiC nanowires can improve the spreading are of Ag–Cu–Ti filler metals on steel substrate with a 9.4% increase amplitude, when the content of SiC nanowires is more than 0.1%, the wettability can be reduced obviously. The addition of SiC nanowires can show little effect on the melting temperature, which results in the same brazing temperature for Ag–Cu–Ti–[Formula: see text]SiC filler metals. With the optimization content of SiC nanowires, the optimal content of SiC is 0.05–0.1%, excessive SiC addition with agglomeration can decrease the wettability and shear strength.