Thickness Of Interfacial Reaction Layer Research Articles

High strength diffusion bonding of Ti2AlNb to GH4169 with (TiZrHfNb)95Al5 high entropy interlayer

A high entropy interlayer (TiZrHfNb)95Al5 was designed for vacuum diffusion bonding of Ti2AlNb to GH4169. The influence of bonding temperature on the interfacial microstructure morphology, mechanical properties and fracture behaviour of the resultant joints was investigated. The evolution of microstructure and fracture mechanism were revealed. The typical interface microstructure of Ti2AlNb/B2/Solid solution/(Ti, Zr, Hf)2(Ni, Nb)+(Ti, Zr, Hf)(Ni, Nb)+(Ti, Zr, Hf)(Ni, Nb)2+Solid solution/(Ti, Zr, Hf)(Ni, Nb)+(Cr, Ni, Fe)ss/(Cr, Ni, Fe)ss/Cr-rich(Cr, Ni, Fe)ss/Ni-rich(Cr, Ni, Fe)ss/GH4169 was formed. As the bonding temperature increased, the thickness of interfacial reaction layer gradually increased, and the shear strength gradually increased until 980 °C, then decreased sharply. The highest shear strength reached 376 MPa at 980 °C for 90 min. The highest microhardness region of 11.79 GPa existed on the GH4169 side, which was mainly composed of (Ti, Zr, Hf)(Ni, Nb) and (Cr, Ni, Fe)ss phases. Meanwhile, the elastic modulus dramatically changed interface formed near this region. The fracture surface morphology indicated typical brittle fracture characteristics such as cleavage steps, transgranular fracture and intergranular fracture. According to the fracture analyses, major cracks initiated in the (Ti, Zr, Hf)(Ni, Nb) phase+(Ti, Zr, Hf)2(Ni, Nb) phase and gradually extended to the (Cr, Ni, Fe)ss phase. Thus, the major crack emerged region was located at the elastic modulus dramatically changed interface.

Achieving optimal Ti content via interfacial reaction layer characteristics of diamond/Cu–Sn–Ti composites

Diamond/Cu–Sn–Ti composites as potential super-hard abrasive products were prepared in this work by spark plasma sintering at 1223 K. The effects of Ti content on the wettability, interfacial reaction layer thickness, and wear resistance of the bulk composite changes were systematically studied. The results revealed that when the Ti content was below 5 wt%, completely uncoated and partially coated diamond grains were still observed, indicating insufficient wettability, and the interfacial reaction layer appeared to be thin. When the Ti content was 5 wt%, all diamond grains were completely coated, and a continuous and stable interfacial reaction layer composed of TiC has been generated, in which the thickness reached a peak value of 1.72 μm. However, when the Ti content exceeded 5 wt%, the formation of brittle Cu41Sn11 phases was observed, which led to inferior wear resistance. The minimum weight loss was obtained at 5 wt% Ti content. Meanwhile, through FIB-TEM, confirmed that the interfacial reaction layer was mainly composed of continuous TiC layer adjacent to diamond and discontinuous TiC layer in the filler metal, and constitute the formation of a high strength metallurgical interfacial bonding layer.

Interface Behavior of Brazing between Zr-Cu Filler Metal and SiC Ceramic

The interface behavior of brazing between Zr-Cu filler metal and SiC ceramic was investigated. Based on the brazing experiment, the formation of brazing interface products was analyzed using OM, SEM, XRD and other methods. The stable chemical potential phase diagram was established to analyze the possible diffusion path of interface elements, and then the growth behavior of the interface reaction layer was studied by establishing relevant models. The results show that the interface reaction between the active element Zr and SiC ceramic is the main reason in the brazing process the interface products are mainly ZrC and Zr2Si and the possible diffusion path of elements in the product formation process is explained. The kinetic equation of interfacial reaction layer growth is established, and the diffusion constant (2.1479 μm·s1/2) and activation energy (42.65 kJ·mol−1) are obtained. The growth kinetics equation of interfacial reaction layer thickness with holding time at different brazing temperatures is obtained.

Strength of resistance spot welding of aluminum alloy AA6061 to carbon steel using different filler materials

Resistance spot welding is a process in where contacting metal surfaces for similar or dissimilar materials are joined by heat generated from resistance to electric current. Carbon steel and aluminum alloy A6061 sheets were welded by using resistance spot welding method in two stages with and without filler materials where copper and zinc were implemented as fillers, where those two materials, particularly the former, has acceptable affinity, therefor better wettability, to both welded metals. The characteristics of weld joint were investigated by measuring the effect of welding current and time on the nugget size and tensile shear strength of the weldment. The results showed that the welding current has an incremental influence on both the nugget size and tensile shear strength for the two cases studied. Also, the results revealed that the copper filler increases the strength of the weldments more than the zinc filler, which is attributed of higher affinity of the copper to both metals. The joint with the maximum tensile shear strength of 47 kN/m2 is obtained at the condition of 15 kA welding current for copper filler and 40 kN/m2 is obtained at the condition of 13 kA. The thickness of interfacial reaction layer decreased from central joints region to the surrounding area.

Effect of alumina impurity on microstructure and properties of alumina based conventionally brazed joints

Mo-Mn metallization of alumina ceramics of different purity has been performed at 1400 °C for 10 min in moisthydrogen and nitrogen atmosphere. Nickel coating has been applied onto the metallized alumina ceramics at 1000 °C for 1 hin a reducing hydrogen atmosphere. Finally, metallized and nickel coated alumina ceramics has been brazed with anothermetallized and nickel coated alumina ceramics using CuAg filler alloy at 900 °C for 10 min in a vacuum furnace at 1×10-6Torr pressure. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysishas been carried out for phase analysis, microstructural investigation and elemental composition analysis. The adhesivestrength of the metallizing layer and brazing strength of the joint have been measured by pull down breaking strengthmethod. SEM study has shown that the width of the interfacial reaction region between the metallizing layer and substrateenhances with increasing the impurity content in the alumina ceramics. It has been observed that the adhesive strength of themetallizing layer depends on the interfacial reaction layer thickness. The adhesive strength of the metallizing layer has beenincreased with increasing the thickness of interfacial reaction layer. High adhesive strength of the metallizing layer as wellas brazing strength has beenachieved for alumina ceramics with high impurity content.

Numerical analysis on the residual stress distribution and its influence factor analysis for Si3N4/42CrMo brazed joint

The residual stress distribution in Si3N4 ceramic-42CrMo steel joints brazed with TiNp-doped Ag–Cu–Ti composite filler has been investigated. The stress distribution in the specimens during cooling and four-point bending was simulated by finite element (FE) calculations using an elastic-plastic model. The FE simulation results indicate that the peak tensile axial residual stresses appear at the Si3N4 edge close to the interface. The experimentally determined joint strength based on the four-point bending test was compared with the results of the FE analysis, showing a reasonable agreement. The residual stress in the Si3N4-42CrMo joint decreases and then increases with the increase of TiNp content, resulting in an optimized joint strength. The consistency of the obtained results suggests that the stress distribution in the brazed joints can be reasonably predicted within the framework of this elastic-plastic FE model. Then the effect of the thickness of brazing layer and interfacial reaction layer on the stress distribution and joint strength was investigated. The FE results indicate that mechanical properties can be improved by increasing the brazing layer thickness and decreasing the thickness of the interfacial reaction layer. Nevertheless, to improve the experimental joint strength, we should carefully consider all critical properties of the joint rather than simply increasing the brazing seam thickness and decreasing the interfacial reaction layer thickness.

Microstructure, mechanical properties, and interfacial reaction with Cu substrate of Zr-modified SAC305 solder alloy

Four component solder alloys (Sn-3.0Ag-0.5Cu-xZr; x = 0, 0.05, 0.2, and 0.5 wt%) were obtained using vacuum induction melting. The microstructure of the solder alloys and solder joints was characterized via OM, SEM, XRD and EPMA. Tensile and shear tests were performed to evaluate the mechanical properties. The results showed that with the increase of the Zr content, the size of the primary β-Sn phases decreased gradually, and Ag3Sn decreased first and then increased. The SAC305-0.2Zr solder exhibited the finest microstructure. The size of the primary β-Sn phase decreased by 59%, and the Ag3Sn resembled a dot 1 μm in size. Tensile tests indicated that as the Zr content increased, the strength of the solder increased, and the elongation first increased and then decreased. Compared to the original joints, the joints fabricated with Zr-modified solders had thinner intermetallic compound (IMC) layers and exhibited higher shear strength. The SAC305-0.2Zr/Cu joints had a 17% reduction in the interfacial reaction layer thickness and a 20% increase in the maximum shear force. Moreover, the Zr-modified solders showed a significant decline in undercooling. The melting range and melting point was slightly reduced. In this study, 0.2 wt% was determined to be the optimum amount of Zr in the SAC305 solder.

Effects of hydrogen on the interfacial reaction between Ti[sbnd]6Al[sbnd]4V alloy melt and Al2O3 ceramic shell

Effects of hydrogen on the interfacial reaction between Ti6Al4V (Ti64) alloy melt and Al2O3 ceramic shell were studied by arc-melting in H2/Ar gaseous mixture. The thickness of interfacial reaction layer between Ti64 alloy melt and Al2O3 ceramic shell without hydrogenation is 80 μm. But the thickness of reaction layer can be reduced to 10 μm at a hydrogen partial pressure of 20 kPa, which is better than the thickness of interface layer between Ti64 alloy and widely used Y2O3 shells. At Ti64 casting surface, the content of β-soft ductile phase is increased and the width of both reaction zone and transition zone are reduced with the increase of hydrogen partial pressure, thus reduces the hardness and the element diffusion distance. Therefore, Hydrogen can effectively control the interfacial reaction in the process of titanium alloy investment casting, and Al2O3 ceramic will be a kind of very promising shell material.

Effect of Interfacial Reaction Layer Thickness on Fracture Morphology and Impact Resistance of Sn-Ag-Cu Solder Bump Joint

Effect of Interfacial Reaction Layer Thickness on Fracture Morphology and Impact Resistance of Sn-Ag-Cu Solder Bump Joint

Protonation effects on dynamic flux properties of aqueous metal complexes

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

Effect of the interfacial reaction layer thickness on the thermal residual stresses in SiCf/Ti–6Al–4V composites

A three-dimensional finite element model was developed to study the effects of the interfacial reaction layer thickness on the distribution of the thermal residual stresses near the interfacial reaction layer in continuous SiC fiber reinforced Ti–6Al–4V composite. The interfacial reaction layer thicknesses in real composites were adopted in the present analysis. The hoop, radial and axial stresses at the fiber and interfacial reaction layer (f/i interface), middle of the interfacial reaction layer and interfacial reaction layer and matrix (i/m interface) were studied for each thickness. The results show the interfacial reaction layer thickness has a significant influence on the distribution of the thermal residual stresses near the interfacial reaction layer. X-ray stress measurements indicate that the prediction data have a good agreement with the experimental results. The interfacial radial cracks appear not only in the as-processed sample but also in the heat-treated samples. Experimental observations suggest that the f/i interfacial debonding is not significant during the transverse tensile loading.

Interfacial Reaction in AZ91D Magnesium Alloy Matrix Composite Reinforced with Aluminum Borate Whisker

AZ91D magnesium alloy reinforced with aluminum borate whisker (Al 18 B 4 O 33w , denoted by ABO w ) was fabricated by squeeze-casting. The heat treatment (T4) was carried out at 693 K in argon atmosphere for 48 and 96 hours, respectively, following water-quenched. The behaviors of interfacial reaction were studied in processes of fabrication and following heat treatment. Microstructures of interfacial reaction layers were investigated with transmission electron microscopy (TEM). Interfacial reaction layer in thickness of 5-10 nm was found in as-casted composite, and it was identified that the interfacial reaction layer was consisted of MgO. When the composite was heat-treated at 693 K for 48 hours, the surfaces of whiskers were covered with interfacial reaction layer completely and the thickness of interfacial reaction layer increased to about 20 nm. With increasing the time of heat treatment from 48 hours to 96 hours, the thickness of interfacial reaction layer on the surfaces of whiskers did not change obviously. The interfacial reaction layer was consisted of tiny MgO particles and a small quantity of MgB 2 particles. Although MgO particles played a good barrier to keep out of contacting between magnesium and whisker, the boundaries between MgO particles acted as a shortcut of magnesium atoms migration. Therefore magnesium could keep on reacting to whisker. The interfacial reaction could invade into the inner of whisker about 20 nm depth after the composite was heat-treated at 673 K for 96 hours. The surfaces of whiskers became wave-like because of interfacial reaction. An orientation relationship was found between MgO reaction layer and ABO w : (111) MgO // (320) ABOw and [011] MgO // [001] ABOw . The surfaces of MgO particles were consisted of close-packed (11 1) MgO plane.

Nb/MoSi2적층복합재료의 제조 및 파괴특성

The impact value. the interfacial shear strength. the tensile strength and the fracture strain of Nb/MoSi₂ laminate composites. which were associated with the interfacial reaction layer. have been investigated. Three types of Nb/MoSi₂ laminate composites alternating sintcred MoSi₂ layers and Nb foils were fabricated as the parameter of hot press temperature. The thickness of interfacial reaction layer of Nb/MoSi₂ laminate composites increased with increasing the fabrication temperature. The growth of interfacial reaction layer increased the interfacial shear strength and led to the decrcase of impact value in Nb/MoSi₂ laminate composites. It was also found that in order to maximize the fracture energy of Nb/MoSi₂ laminate eomposites. interfacial shear strength and the thickness of interfacial reaction layer must be secured appropriately.

Effect of Interfacial Shear Strength on Impact Properties of Nb/MoSi<SUB>2</SUB> Laminate Composites

The relationship between the interfacial shear strength and the impact properties of Nb/MoSi 2 laminate composites have been investigated, in conjunction with the evaluation of their fracture strain and the thickness of interfacial reaction layer. Nb/MoSi 2 laminate composites have been fabricated by stacking sintered MoSi 2 sheets and Nb sheets, alternately and hot pressing in the griphite mould. The instrumented Charpy impact test, the interfacial shear test and the tensile test was carried out at the room temperature. To change the interfacial shear strength associated with the thickness of interfacial reaction layer, Nb/MoSi 2 laminate composites were fabricated as the parameter of hot press temperature. It is found that the interfacial shear strength between MoSi 2 and Nb increases with the growth of the interfacial reaction layer, which results from the increase of fabricating temperature. Such a increase of the interfacial shear strength leads to a localized deformation of Nb foil and then deteriorates the enhancement of impact value in Nb/MoSi 2 laminate composites. There is obviously an appropriate interfacial shear strength capable of maximizing the impact value in this composite system, associated with the plastic deformation of Nb foil.

Interfacial Reactions in the Joining of Si3N4/Si3N4 with Newly Developed CuNiTiB Brazing Alloy

Joing of Si3N4/Si3N4 was carried out with a newly developed Cu68Ni10Ti21B1 brazing alloy. With the powdered new brazing alloy, the shear strength of the joints reaches 233 MPa. With the rapidly-solidified foils of the brazing alloy, the three-point bend strength of the joints is raised to 406 MPa at room temperature and this value is kept until 723K. The interfacial reactions of the joint and its effects on the joint strength are discussed. The lattice matching between Si3N4 and Ti5Si3 is better than that between Si3N4 and TiN. So the formation of Ti5Si3 rather than TiN at the interfaces is favorable to the joint strength. Adding element Ni to Cu-Ti alloy can weaken the activity of Ti in the alloy, which is favorable to decrease the thickness of interfacial reaction layer and in the result the joint strength is increased. An adding a small amount of B in the new alloy can decrease its liquidus temperature.

Model-based simulation of the consolidation processing of metal coated fibers

The consolidation of metalized ceramic fibers by hot isostatic pressing (HIP) offers an attractive route for the manufacture of continuous fiber reinforced titanium matrix composites (TMCs). The performance of this class of composites is controlled by the fiber/matrix properties and by the composite's relative density, the grain size of the matrix alloy and the interfacial reaction layer thickness at the fiber–matrix interface after processing. Recently developed process models that predict the evolution of these microstructural attributes during consolidation processing are summarized and combined with consolidation equipment dynamics to simulate the microstructural evolution of PVD Ti–6Al–4V coated Sigma 1240 (SiC) monofilaments during HIP. For this system, diffusion accommodated grain sliding is the dominant densification mechanism for process cycles that preserve the refined grain size of the PVD metal coating.

Simulation of microstructural evolution during TMC monotape consolidation processing

The consolidation of fiber-reinforced titanium matrix composite (TMC) monotapes produced by spray deposition is an important step in the manufacture of TMC components. The performance of this class of composites is controlled by fiber-matrix properties and by the composite's relative density, fiber microbending stress/fracture and by the interfacial reaction layer thickness at the fiber-matrix interface after processing. These three microstructural features evolve during consolidation processing. Models for predicting the microstructure's dependence upon process conditions (i.e. the time varying pressure and temperature) are combined with consolidation equipment dynamics to simulate the microstructural evolution and to assess the relative “processibility” of several silicon carbide fiber-titanium alloy matrix systems during their transient consolidation processing. The dependence of the microstructural state upon the material system's mechanical properties and the monotape's initial geometry has also been investigated and is used to propose guidelines for the selection of TMC system materials and monotape geometry parameters.

Joining of Zirconia Ceramic to Stainless Steel and to Itself Using Ag57Cu38Ti5 Filler Metal

The brazing of ZrO2 ceramic to 1Cr18Ni9Ti stainless steel and to itself was performed using Ag57Cu38Ti5 filler metal under a vacuum of 7 × 10‐3 Pa. The effects of interlayer copper on the ceramic to stainless steel joint strength, and the brazing temperature (1073 to 1323 K) and holding time (0 to 60 min) on ceramic to ceramic joint strength were investigated. The joint strength was evaluated by shear testing. An interfacial reaction layer between the ceramic and the filler metal was found, and the reaction products were δ‐TiO and γ‐AgTi3. The joint strength of ZrO2 ceramic to stainless steel was improved by using a layer of copper of a suitable thickness. The brazing temperature and holding time had a strong influence on the joint strength of ceramic to ceramic, and the joint strength was mainly controlled by reaction layer thickness and the properties of the reaction products. The maximum shear strength was obtained for brazing at 1123 K for 30 min and an interfacial reaction layer thickness of ∼4.4 μm.

Kinetics of interlayer formation on polycrystallineα-Al2O3/copper-titanium alloy interface

Copper-titanium alloys are known to wet an alumina surface. Traditionally, contact angles are used as measurable parameters to monitor the progress of wetting. Contact angle is a measure of the thermodynamic equilibrium at the interface. For reactive wetting systems, it is well known that the interfacial properties vary as a function of time. In the present study, kinetics of reaction were studied by monitoring the rate of interfacial phase formation. An immersion apparatus was built for this purpose. The extent of reaction was measured both by a simple surface compositional analysis and by interfacial reaction layer thickness measurements. The reaction layer exhibited a parabolic growth with an associated activation energy of 180 to 230 kJ/mole. A speculative growth mechanism is proposed based on the experimental observations and the information available in the literature.

摩擦圧接した１０５０アルミニウムとＡＺ３１マグネシウム合金の接合界面

Bonding interfaces of friction-welded 1050 aluminum/AZ31 magnesium alloy joints, before and after annealing at 673K for 1h, were examined by tensile test for bonding strength, by optical micrography, EPMA and X-ray analysis for phases in the interfacial reaction. Bonding strength of the friction-welded joints in the as-welded state was dependent on the thickness of interfacial reaction layer. The thinner layer had resulted in the higher bonding strength (about 45MPa). The interfacial reaction layer consisted of two sublayers of compounds (Al3Mg2 and Al12Mg17). The former compound predominantly grew by the annealing. That fact resulted in the brittlement of the interface.