Effect Of Intermetallic Compounds Research Articles

Microstructure evolution and multi-reinforcement mechanisms in Al-Cu-Ag alloys

As one of the most commonly used binary alloys, the effect of intermetallic compounds (IMCs) of Al-Cu alloys in powder metallurgy on their structure and properties is instructive for tailoring Al-Cu alloys for different applications. In this investigation, a series of Al-Cu-Ag alloys with varying Cu compositions were fabricated via hot pressing. TEM analysis identified CuAl2 as the primary intermetallic compounds, with Ag existing in forms including Ag2Al, elemental Ag, and an Ag-(Cu) solid solution. The modulation of Cu content influenced the state of Ag and the mechanical behaviors of the Al-Cu-Ag alloy. Particularly, the high Al/Cu alloy, benefiting from a synergistic effect comprising stacking faults, nanoscale precipitates, and solid solutions, exhibited outstanding mechanical properties. Conversely, the Al-50Cu-3Ag alloys displayed significant brittleness, attributed to the adverse impact of large-scale intermetallic compounds and increased grain size due to the formation of CuAl2. The incorporation of nanoparticles effectively mitigated the grain size in high Al/Cu alloys. This study elucidates the correlation between the evolution of intermetallic compounds and composition in Al-Cu alloys, offering novel insights into the reinforcement of both Al-based and Cu-based alloys.

Formation and effect of intermetallic compounds in the vacuum arc melting of titanium/copper alloy

The effect of Ti element content on the precipitation of intermetallic compounds, microstructure and mechanical properties of Ti–Cu alloy samples during vacuum arc melting was studied. The results showed that when the TC4:Cu mass ratio were 1:20, 1:10, and 3:20, the tensile strength of the sample were 638 MPa, 945.5 MPa, 914.9 MPa, the elongation were 21.1 %, 3.5 %, 0.9 %, and the microhardness were Hv 195.6, Hv 259.01, Hv 275.6, respectively. The solidification behavior of the melt pool and the precipitation behavior of IMCs were also studied. When the Ti content exceeds the solid solubility of titanium in copper, dendrite segregation will occur during the solidification process, resulting in the precipitation of a large number of IMCs. The IMCs precipitated in Ti–Cu melting samples include TiCu, Ti3Cu4, TiCu3, and TiCu4. Among them, TiCu4 is precipitated from the solid solution due to the decrease in melt temperature in the later stage of solidification, while TiCu, Ti3Cu4, and TiCu3 are produced by liquid-phase precipitation or transformation reaction of the TiCu phase. TiCu and Ti3Cu4 are the main causes of alloy fracture.

Effect of intermetallic compounds on the high-temperature oxidation resistance of Al0.25CoCrFeNiCuAux (x = 0, 0.1, 0.3) high-entropy alloys

In this work, the effect of gold alloying on the microstructure, phase composition, and high-temperature oxidation resistance of Al0.25CoCrFeNiCu high-entropy alloy (HEA) was studied. It is shown that gold is partly incorporated in the dendritic face-centered cubic (fcc) phase, and it is mainly precipitated as intermetallic compounds (ICs) in the interdendritic space. Al2Au and AuCu3 ICs could be precipitated depending on the concentration of gold. The formation of Al2Au ICs increased the parabolic oxidation rate constant (kp) from 378.5 × 10–13 (g2/cm4s) for Al0.25CoCrFeNiCu to 1079.5 × 10–13 (g2/cm4s) for Al0.25CoCrFeNiCuAu0.1 HEA, while the precipitation of AuCu3 in Al0.25CoCrFeNiCuAu0.3 HEA reduced this index to kp = 94.9 × 10–13 (g2/cm4s). Microstructural analysis of the oxidized samples revealed that binding of aluminum into Al2Au IC decreases the amount of available aluminum in the solid solution phase to form a protective Al2O3 oxide layer on the surface of Al0.25CoCrFeNiCuAu0.1 alloy during high-temperature oxidation. On the contrary, the binding of copper with gold into AuCu3 IC effectively prevents Cu from oxidation and provides routes for the formation of a dense layer of Al2O3 oxide with superior protective properties.

Formation and effect of intermetallic compounds in the interface of copper/aluminum composites under rolling conditions

Rolling and annealing are common composite processes of Copper/Aluminum composites (Cu/Al), but the formation of intermetallic compounds (IMCs) at Cu/Al interfaces and their relationship with processing conditions still lack a nanoscale understanding. Here, we use molecular dynamics (MD) method to simulate the formation of IMCs at Cu/Al interface under different rolling and annealing process parameters with their formation mechanisms quantitatively analyzed. XRD, RDF and potential energy analysis show that rolling promotes the formation of interfacial IMCs, because copper and aluminum atoms tend to diffuse into each other at the interface and combine to form IMCs during rolling. The effects of different size ratios of copper to aluminum and annealing on IMCs are also evaluated. By studying the equivalent phonon thermal conductivity of the interfacial layer and shear strength, it is shown that IMCs enhances interfacial phonon heat transfer, but reduce the interfacial shear strength due to their brittle and hard properties. In addition, the rolling and annealing processes are able to change the dislocation density, thereby affecting the phonon scattering and shear strength of Cu/Al. These results are expected to guide improved directions for the process optimization of high-performance Cu/Al.

The Effect of Intermetallic Compounds on Corrosion and Tribocorrosion Behavior of 7075 Aluminum Alloy

The Effect of Intermetallic Compounds on Corrosion and Tribocorrosion Behavior of 7075 Aluminum Alloy

The Effect of IMCs and Segregation on the Microstructure and Mechanical Properties of β-Type Titanium Alloys

Two new β-type titanium (β-Ti) alloys of Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al and Ti-15.6Cr-12Mn-3.3Zr were designed with the same bond order value 2.79 and different d-orbital energy level values of 2.28 and 2.16, respectively. The effect of intermetallic compounds (IMCs) and the segregation behaviors of β-Ti alloys were discussed by adding excessive and normal alloying elements to alloys under both as-cast and solution-treated conditions. The mono-β phase in the Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al alloy and β+intermetallic compounds (IMCs) in the Ti-15.6Cr-12Mn-3.3Zr alloy were identified and observed. The as-cast and solution-treated alloys showed their ultimate tensile strength and fracture strain; these were 982 and 1002 MPa, with 9.82 and 9.89% for Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al, and 448 and 296 MPa, with 0.12 and 0.11% for Ti-15.6Cr-12Mn-3.3Zr, respectively. Moreover, the Vickers hardness values of the as-cast and solution-treated alloys were 345 and 355 for Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al, and 422 and 466 for Ti-15.6Cr-12Mn-3.3Zr, respectively.

Effect of Intermetallic Compounds on Mechanical and Microstructural Properties of Dissimilar Alloys Al-7Si/AZ91D

Effect of Intermetallic Compounds on Mechanical and Microstructural Properties of Dissimilar Alloys Al-7Si/AZ91D

Effect of intermetallic compound on the corrosion behaviour of resistance spot welding joints between 5182 aluminium alloy and galvanized DP780 dual-phase steel

Interfacial intermetallic compound (IMC) layer is critical during realizing the galvanic corrosion mechanism and strength degradation of aluminium/steel resistance spot welding (RSW) joints. The effect of IMC layer on the corrosion behaviour of RSW joint between 5182 aluminium alloy and galvanized DP780 dual-phase steel was investigated by immersion corrosion method and electrochemical method. Results demonstrated localized corrosion around Fe-rich phase particles on aluminium nugget and preferential corrosion at the interface front near IMC layer. The IMC layer had the highest open circuit potential value of −0.569 V and low corrosion current density among the investigated nugget and substrates. The potential difference (0.184 V) between the cathodic IMC layer and large area of anodic aluminium nugget was responsible for the preferential initiation of localized corrosion at the interface front near the IMC layer.

Interfacial intermetallic compound modification to extend the electromigration lifetime of copper pillar joints

Electromigration is the massive metal atom transport due to electron flow, which could induce a disconnect in electronics. Due to the size of copper pillar bump reduction, the portion of interfacial intermetallic compound in solder joints is increasing obviously. However, there is lack of systematical research on the effects of intermetallic compound on the EM lifetime of solder joints. In this paper, the interfacial intermetallic compound of copper pillar joints is modified to extend the electromigration lifetime. The growth rate of intermetallic compound in solder joints sample is calculated firstly. From 230°C to 250°C, the growth rate of intermetallic compound increases from 0.09 μm/min to 0.19 μm/min. With a longer reaction time, the intermetallic compound layers continuously grow. Then electromigration tests were conducted under thermo-electric coupling loading of 100°C and 1.0 × 104 A/cm2. Compared with lifetime of thin and thick intermetallic compound samples, the lifetime of all intermetallic compound sample improved significantly. The lifetime of thin, thick, and all intermetallic compound samples is 400 min, 300 min, and 1,200 min, respectively. The failure mechanism for the thin intermetallic compound sample is massive voids generation and aggregation at the interface between solder joints and pads. For the thick intermetallic compound sample, the intermetallic compound distance is short between cathode and anode in solder joints, leading to lots of crack create in the middle of solder joints. As the all intermetallic compound sample can greatly reduce the number of voids generated by crystal structure transforming, the lifetime extend obviously.

Effect of intermetallic compounds on interfacial bonding of Al/Fe composites

The effects of Pure Al/Pure Fe and Al + 0.88Si/Fe + 1.48Si intermetallics on the interfacial bonding properties of Al/Fe composites were studied. The results showed that: When there was no Si addition, IMC was just formed, when the thickness was between 200 nm and 500 nm, there was no crack in the interface and the bonding strength was high. With the increase of IMC thickness, discontinuous compounds began to form on the interface, crack appeared on the Al side of the interface, the bonding strength decreased slightly. With the extension of heat treatment time, IMC became continuous distribution, the crack length and width increased obviously, the interfacial bonding strength decreased significantly. After the addition of Si, the IMC was mainly discontinuous, and the interface did not form crack. Under the similar IMC thickness, the interface bonding strength was much higher than that of the composites without Si.

Effect of Intermetallic Compounds on Pitting Corrosion of Spark Plasma Sintered AA2024

The microstructures and electrochemical pitting behaviors of AA2024 in successive spark plasma sintering, solid solution treatment (SST), and aging treatment (AT) states were investigated. The effect of intermetallic compounds (IMCs) on corrosion behaviors of AA2024 was analyzed. It was observed that the number and size of IMCs decreased after SST, and increased again after subsequent AT. The as-SST sample showed the best pitting resistance. Corrosion morphologies analysis indicated that pits initiated at the periphery of IMCs, both the big and small particles might be the nucleation sites of pits. For the sintered AA2024, after immersion in 3.5 wt% NaCl solution for 30 min, the critical size for IMCs causing pits is 0.107 μm2. For the IMCs bigger than this size, whether pits initiate around them during immersion depended on the potential difference of these particles with the matrix.

Effect of Intermetallic Compounds on the Microstructure, Mechanical Properties, and Tribological Behaviors of Pure Aluminum by Adding High-Entropy Alloy

Effect of Intermetallic Compounds on the Microstructure, Mechanical Properties, and Tribological Behaviors of Pure Aluminum by Adding High-Entropy Alloy

Corrosion resistance of Mg-Al-LDH steam coating on AZ80 Mg alloy: Effects of citric acid pretreatment and intermetallic compounds

In this study, the effects of intermetallic compounds (Mg17Al12 and Al8Mn5) on the Mg-Al layered double hydroxide (LDH) formation mechanism and corrosion behavior of an in-situ LDH/Mg(OH)2 steam coatings on AZ80 Mg alloy were investigated. Citric acid (CA) was used to activate the alloy surface during the pretreatment process. The alloy was first pretreated with CA and then subjected to a hydrothermal process using ultrapure water to produce Mg-Al-LDH/Mg(OH)2 steam coating. The effect of different time of acid pretreatment on the activation of the intermetallic compounds was investigated. The microstructure and elemental composition of the obtained coatings were analyzed using FE-SEM, EDS, XRD and FT-IR. The corrosion resistance of the coated samples was evaluated using different techniques, i.e., potentiodynamic polarization (PDP), electrochemical impedance spectrum (EIS) and hydrogen evolution test. The results indicated that the CA pretreatment significantly influenced the activity of the alloy surface by exposing the intermetallic compounds. The surface area fraction of Mg17Al12 and Al8Mn5 phases on the surface of the alloy was significantly higher after the CA pretreatment, and thus promoted the growth of the subsequent Mg-Al-LDH coatings. The CA pretreatment for 30 s resulted in a denser and thicker LDH coating. Increase in the CA pretreatment time significantly led to the improvement in corrosion resistance of the coated AZ80 alloy. The corrosion current density of the coated alloy was lower by three orders of magnitude as compared to the uncoated alloy.

Effect of intermetallic compounds on the mechanical property and corrosion behaviour of aluminium alloy/steel hybrid fusion-brazed welded structure

Al alloy/steel joint was produced by fusion-brazing welding with different heat inputs to obtain intermetallic compounds (IMCs) layer with different thicknesses. Following by enhancing heat input, not only the FeAl binary IMCs (Fe2Al5 and Fe4Al13) became thicker at the interface, the formation of Fe-Al-Si ternary IMCs, such as Fe2Al8Si, also became evident. Nevertheless, the joint strength was maintained at a high level. An increase of corrosion current density with three orders of magnitude was identified when the joint was welded under a high heat input (>632 J/cm) due to the appearance of enhanced tunnelling corrosion caused by ternary IMCs with weld seam. Binary IMCs became less corroded with the increase of heat input arising from the cathodic corrosion protection. Therefore, a low heat input should be utilised to preserve the corrosion resistance of the joint, while keeping its mechanical performance.

Effect of Intermetallic Compounds on Thermal Resistivity of Solder Joints

Effect of Intermetallic Compounds on Thermal Resistivity of Solder Joints

Effect of Intermetallic Compounds on the Microstructure, Mechanical Properties, Wear, and Fracture Behavior of Ni/Ti Laminated Composite

Effect of Intermetallic Compounds on the Microstructure, Mechanical Properties, Wear, and Fracture Behavior of Ni/Ti Laminated Composite

Microstructures and mechanical properties of as-extruded Mg–8Gd–2Y–1Zn–6Li alloy

In this study, a high-performance Mg–8Gd–2Y–1Zn–6Li (wt%) alloy having a TYS of 202 ± 2.6 MPa, UTS of 243 ± 2.1 MPa and EL of 10.7 ± 2.3% was successfully fabricated by casting, heat treatment and hot extrusion. The effects of intermetallic compounds on microstructure and mechanical properties were deeply investigated. The results show that the studied alloy consists of coarse deformed α-Mg grains with (0001) basal texture, fine recrystallized β-Li grains with (002) texture and three Mg3RE phase variants, which are bulk Mg3RE phase with a size range of 10–30 µm, spot Mg3RE phase with a size range of 1–2 µm and spherical Mg3RE phase with a size range of 0.3–1 µm, respectively. The spherical Mg3RE phase has a strong dispersion strengthening effect, while the bulk Mg3RE phase acts as crack resources and deteriorates the ductility. A novel island-like β1R phase (FCC, a = 0.78 nm) is found for the first time in the Mg-Gd-Li based alloys. It has a coherent (1̅12)β1R//(101̅0)α interface at the broad facet and a semi-coherent (1̅11)β1R//(112̅0)α interface at the end facet. The β1R phase transforms from βH phase at the semi-coherent interface by atomic shear of RE and Mg atoms. The β1R phase provides a significant precipitation strengthening effect to the studied alloy, while the dissolution of β1R phase results in the age-softening phenomenon. The high-performance of the studied alloy is mainly attributed to the α/β duplex structure, three Mg3RE phase variants, and β1R phase.

Effect of intermetallic compounds (IMCs) on the interfacial bonding strength and mechanical properties of pre-rolling diffusion ARBed Al/Ti laminated composites

A combination of pre-rolling diffusion process (PR) and accumulative roll bonding (ARB) was applied to fabricate multilayered Al/Ti laminated composite with a great emphasis on the effect of the optimized interface structure on mechanical properties. The evolution of microstructure and mechanical properties during PR process were analyzed. We found that compared to the conventional rolling process (CR), a better combination between strength and ductility was achieved after the PR process, which was attributed to the improved interface bonding. In addition, the inhomogeneous microstructural distribution in multilayered Al/Ti laminated composites indicated that their formation was related to the friction between roller and sheet surface and the inhomogeneous deformation between constituent layers. The annealing behavior at 550 °C for various times in terms of the growth kinetic and structure of intermetallic compound (IMC) and its effect on the mechanical properties were studied. The evolution of the thickness of the IMC layer and quantitative analysis revealed that the growth behavior obeyed a two-stage development for various periods of time. Such unusual growth behavior was attributed to the effect of grain size in the IMC layer, which caused the grain boundary diffusion. Furthermore, an increasing fraction of fined grains, which was introduced by the IMC layer after annealing, strengthened the Al/Ti laminated composite.

Impact of Mechanical Property Degradation and Intermetallic Compound Formation on Electromigration-Oriented Failure of a Flip-Chip Solder Joint

Due to the increased complexity and optimization in microprocessor packaging from 2D to 3D packages, the size of solder joints is being reduced significantly. This trend currently leads to an increased amount of current density across flip-chip solder joints as well as microbumps and causes electromigration-oriented void formation and subsequent failure of the solder joints. It has been observed from literature that solder material undergoes microstructure evolution and subsequent degradation of mechanical properties under isothermal aging conditions. The current study is based on the effects of material property degradation due to thermal aging of flip-chip Sn-Ag-Cu (SAC) solder joints on electromigration-oriented failure. Finite element analysis has been used to analyze the diffusion characteristics of a SAC solder joint under isothermal aging conditions of 100°C for a period of 1–20 days, and electromigration simulation has been performed at two different temperatures of 100°C and 125°C for 100 h at an input current range of 0.01–0.05 A. The effect of intermetallic compound (IMC) layer thickness is analyzed to reveal the impact on electromigration-oriented failure in isothermally 60 days long aged solder bumps. Results have revealed that resistance to electromigration-oriented failure is higher in the case of aged components compared to unaged components along with the increment of time to failure with IMC formation in the SAC solder joint.

Effects of intermetallic compounds on the thermophysical properties of uranium –palladium alloys

The formation and migration of high-yield lanthanide fission products during reactor operation and fuel reprocessing stages continues to be a critical area of concern for evaluating the performance of metallic fast-reactor nuclear fuels, particularly the formation of lanthanide-Fe eutectic compounds at the fuel-clad interface. Palladium has been shown to be an effective fuel additive for reducing fuel-clad chemical interaction (FCCI) by binding up lanthanide fission products and preventing their interaction with cladding materials, yet very little data exists for thermodynamic and thermal transport properties of actinide-palladium alloys. To better understand the effect of U–Pd intermetallic compounds on the thermophysical properties of metallic uranium, the phase transition temperatures (Ttr) and enthalpies (ΔHtr), specific heat capacities (Cp), thermal diffusivities (D), and the densities (ρ) as a function of temperature were experimentally measured or calculated for a series of alloys in the U–Pd binary system in a temperature range from 300 to 1173 K. These values were used to calculate the thermal conductivity (k) as a function of temperature for each composition and are reported in this paper. The addition of Pd led to an increased weight fraction of UPd3 as well as a substantial reduction in both D and ρ, and a small decrease in Cp at most temperatures measured. Consequently, the addition of 5 and 10 wt % Pd to U lead to a net decrease in k values of 23 and 40%, respectively, across the entire temperature range.