Sn Alloy Research Articles

The influence of microalloying and preparation process on phase transformation, mechanical properties, and friction/corrosion behavior of Cu–Ni–Sn alloys: A review

This review provides an overview of Cu–Ni–Sn alloys, which have great advantages as a potential substitute for beryllium bronze. The characteristics of spinodal decomposition in Cu–Ni–Sn alloys are thoroughly discussed by conducting a comprehensive analysis of thermodynamics and the phase diagram. The traditional casting process for Cu–Ni–Sn alloys is subject to several limitations, including segregation during solidification as a primary constraint. Another significant limitation is the occurrence of discontinuous precipitation during aging. Thus, the strategies to overcome these limitations are further elaborated. Commonly used methods include thermal-mechanical processing and composition design. Finally, the application of Cu–Ni–Sn alloys in friction and corrosion is discussed. The purpose of this review is to provide a comprehensive summary of the research progress and significant limitations encountered in Cu–Ni–Sn spinodal alloys. This includes a discussion of traditional casting methods as well as novel preparation techniques. The aim is to serve as a valuable reference for the development of new manufacturing methods and the future advancement of Cu–Ni–Sn spinodal alloys.

Effects of Sn addition on precipitation of a pre-naturally aged Al–Zn–Mg alloy during artificial aging

The effect of Sn addition and pre-natural aging on the artificial aging behavior of Al–Zn–Mg alloy was investigated using both experimental approaches and first principle study. The result shows that Sn retards hardness increase at the initial stage of artificial aging by inhibiting the formation of Guinier-Preston zones (I). Atom probe tomography and density functional theory have revealed that the high binding energy of Mg-Sn disturbs Mg-Zn clustering and delays the formation of Guinier-Preston zones (I). However, the retardation effect of Sn on the artificial aging was found to be suppressed when the pre-natural aging was applied to the Al–Zn–Mg–Sn alloy: hardness at the initial stage increased rapidly compared to the Al–Zn–Mg alloy with pre-natural aging. The reason for the rapid increase of hardness in the Al–Zn–Mg–Sn alloy with pre-natural aging is that Guinier-Preston zones (II) was directly formed from vacancy-rich clusters in the Al–Zn–Mg–Sn alloy in contrast to the Al–Zn–Mg alloy with pre-natural aging. This means Mg-Sn and Zn-rich cluster formed during pre-natural aging can accelerate precipitation kinetic by providing nucleation site for Guinier-Preston zones (II) during artificial aging.

An effective method for recovering ultrafine SnO2, MgSn(OH)6, and Zn from complex iron tailings

The generation of complex tailings from iron mining is continuously increasing, reaching a reserve of 500 million tons. The iron tailings mainly contain 0.10–0.50 wt% ultrafine SnO2 (−9.6 μm, >50 %), acid-solule Sn (MgSn(OH)6) and 0.20–1.50 wt% Zn and are recognized as an important secondary Sn resource. Unfortunately, traditional mineral processing techniques have a low Sn recovery ratio. In this study, a novel method is proposed for effectively recovering Sn and Zn from complex iron tailings through reduction-sulfurization roasting, and their transformation behavior is determined. The results reveal that MgSn(OH)6 is first transformed into MgSnO3 at 1073 K, and SnO2 is reduced to SnO(g) and then sulfurized to SnS(g). COS acts as the main curing agent during the roasting process, which originates from the oxidation of FeS. As the temperature increases from 1173 to 1273 K, part of SnO2 can combine with CaO to form Ca2SnO4, and the generated CaSnO3 and MgSnO3 are further reduced to Sn(l) and Fe–Sn alloy. Meanwhile, ZnO and ZnS can be efficiently converted to Zn(g). Interestingly, the Fe–Sn alloy cannot be removed due to low Sn activity (a[Sn]). However, the Sn recovery ratio increases to 90 % due to low SnS partial pressure (PSnS) at 1373 K. Under optimal conditions, 90.10 wt% Sn and 94.90 wt% Zn can be extracted in the dust, which can be further processed into higher value-added Sn concentrate. Compared with current beneficiation process, the recovery ratio of SnO2 increased by 20 %. More importantly, MgSn(OH)6 can be efficiently recovered. This is of great significance for sustainable metallurgy of Sn.

Controlling Volatility and Nonvolatility of Memristive Devices by Sn Alloying

Controlling Volatility and Nonvolatility of Memristive Devices by Sn Alloying

Mechanical property of the shape memorable Ti–Zr–Nb–Sn alloy manufactured by in-situ alloying in directed energy deposition

Ni-free β-type Ti alloys have been developed to manufacture high-strength, low-elastic-modulus, shape-memorable medical, and non-toxic components. Because the machinability of these alloys is generally poor, processing via additive manufacturing is an important step in the development of order-made medical devices. Although many studies evaluated the mechanical properties of additively manufactured Ni-free β-type Ti alloys, investigation of their heterogeneous microstructure resulting from the rapid melting-solidification cycling has not been discussed yet. In this study, the role of a heterogeneous microstructure on the performance of an in-situ alloyed Ti–Zr–Nb–Sn alloy was investigated. The metastable and nanosized ω phase, which is initiated in the non-equilibrium environment, enhances the yield strength without severe ductility degradation. Additionally, deformation-induced martensitic transformation occurs near the unmelted particle/matrix interface, and this phase transformation not only contributes to transformation-induced plasticity but also provides a superelasticity to the present alloy. Although the remained partially melted particle induces a localized corrosion in the matrix, the present results show that the heterogeneous microstructure of the in-situ alloyed Ti–Zr–Nb–Sn alloy exhibits outstanding mechanical properties and superelasticity, which will be suitable to fabricate biomedical parts via additive manufacturing.

Tailoring hierarchical porous core–shell SnO2@Cu upon Cu–Sn alloys through oxygen binding energy difference for high energy density lithium-ion storage

Rational design and construction of self-supporting anodes with high energy density is an essential part of research in the field of lithium-ion batteries. Tin oxide (SnO2) is restricted in application as a prospective high energy density anode due to inherent low conductivity and huge volume expansion of the charge/discharge process. A new strategy that combines high energy ball milling and nonsolvent induced phase separation (NIPS) method was employed to synthesize self-supporting electrodes in which porous SnO2 was encapsulated in a three-dimensional hierarchical porous copper (Cu) shell structure (3DHPSnO2@Cu). This unique structure was constructed due to the different binding energy of the alloy with oxygen, which are −0.91 eV for Cu41Sn11 and −1.17 eV for Cu5.6Sn according to the density functional theory calculation. 3DHPSnO2@Cu electrodes exhibited excellent discharge capacity with an initial reversible capacity of 4.35 mAh cm−2 and a reversible capacity of 3.13 mAh cm−2 after 300 cycles at a current density of 1.4 mA cm−2. It is attributed that the porous Cu shell encapsulated with porous SnO2 provides buffer volume. Among them, the SnO2-Cu-SnO2 interface increases the electrical conductivity and the porous structure provides ion transport channels. This strategy opens a new pathway in the development of self-supporting electrode materials with high energy density.

Effect of Sn Addition on the Microstructure and Age-Hardening Response of a Zn-4Cu Alloy

The aim of this research is to assess the influence of Sn inclusion on the microstructure evolution and age-hardening response of a Zn-4Cu alloy. This is the first study to correlate the age-hardening response to the microstructure of Zn-4Cu alloy reinforced with different Sn contents. A series of Zn-4Cu-Sn alloys were successfully fabricated with different Sn concentrations in the range of 0.0–4.0 wt.% using permanent mold casting. The microstructure of Zn-4Cu-Sn alloys was investigated by means of a scanning electron microscope (SEM) attached with an energy dispersive spectroscope (EDS) and X-ray diffraction (XRD) line profile analysis. At room temperature, the Vickers microhardness measurements were used to assess the age-hardening response of alloys. The results show that the microhardness of the Zn-4Cu (ZC) binary alloy increases a little bit from 76 to 80 HV as the aging time increases from 2 to 128 h, respectively. For aging times up to 16 h, the microhardness of all Sn-containing alloys decreases but then increases again. The lowest hardness belongs to the ZC-1.5Sn alloy, and the Sn-Zn-3.0Sn alloy has the highest; the other alloys fall somewhere in between. At high aging times (64 and 128 h), the microhardness of all Sn-containing samples increased continuously with an increasing Sn content from 0.0 to 3.0 wt.%. When the Sn-containing alloys (3.5 and 4.0 wt.% Sn) were aged for 64 and 128 h, the hardness declined by 7.94% and 8.90% compared to their peak aging hardness values, respectively. By considering the structural changes that occur in the Zn-4Cu-Sn alloys, the reasons for the observed variations in microhardness data with increasing Sn content and aging time were elucidated. X-ray diffraction (XRD) data was analyzed to determine the zinc matrix’s lattice parameters, c/a ratio, and unit cell volume variations.

Rapidly induced homogenization and microstructure control of Cu–15Ni–8Sn alloy by electropulsing treatment

The homogenization heat treatment is a key procedure to controlling the second phase, enhancing composition uniformity and workability of as-cast Cu–15Ni–8Sn alloy. Nonetheless, high annealing temperature and long holding time result in high energy consumption, high costs and severe oxidation. The effects of electropulsing treatment (EPT) and conventional homogenization treatment (CHT) on the microstructure and mechanical properties of Cu–15Ni–8Sn alloy by downward continuous casting were studied. The results showed that with increase of pulse current density, the treatment temperature of the alloy increased continuously. Subsequently, γ-(Cu, Ni)3Sn phase and lamellar (α+γ) phase underwent progressive spheroidizaiton and dissolution. Compared with CHT, EPT contributes to significant reductions in both treatment temperature (about 100 °C) and treatment time (1/34 of the CHT), the tensile strength decreased from 437 Mpa (as-cast alloy) to 380 MPa, while the elongation increased dramatically from 9.2 % to 41.6 %. Compared with being treated by CHT, the alloy treated by EPT performed excellent comprehensive mechanical properties. The extra free energy provided by EPT diminishes the thermodynamic energy barrier of γ phase dissolution and significantly accelerates atomic diffusion, which mainly contribute to rapid homogenization of Cu–15Ni–8Sn alloy by EPT at lower temperature. EPT can work as a novel homogenization heat treatment process for metallic materials, boasting advantages such as high efficiency, low energy consumption and low costs.

Universal interface-confined strategy for trough-like AgPtM (M=Ru, Ir, Sn) nanostructures for methanol electro-oxidation

AgPt-based tri-metallic electrocatalyst as an emerging electrocatalyst is demonstrated to have superior catalytic performance. However, it still lacks a universal synthesis strategy currently because of the participation of multiple precursors with different electrical reduction potentials, which is greatly limited to developing high-performance electrocatalysts. Here, a universal interface-confined strategy method is developed to transform the starting Ag nanowires into a series of novel AgPtM (M=Ru, Ir, Sn) alloy nanotroughs at water/air interface. Moreover, owing to their unique trough-like structure, rough surface and the electronic synergistic effect between oxyphilic metals and Pt component, the AgPtM (M=Ru, Ir, Sn) alloy nanotroughs all show enhanced electrocatalytic performance for methanol electro-oxidation. Notably, among all the prepared AgPtM (M=Ru, Ir, Sn) catalysts, the AgPtRu exhibits the best mass activity, ∼ 3.7 and ∼1.65 times higher than that of Pt/C and AgPt nanotroughs counterpart, respectively. This study not only develops a new promising electrocatalyst for methanol oxidation, also provides method guidance for the construction of advanced Pt-based tri-metallic electrocatalysts in practical direct alcohol fuel cell.

Microstructure and Superelasticity of Cu–Sn Shape-Memory Microwires by Glass-Coated Melt Spinning

Cu–Sn shape-memory microw ires were fabricated by a glass-coated melt spinning method. Effects of Sn content on the microstructure and mechanical properties of microwires were investigated. The phase transforms from martensite to austenite with an increase in Sn from 14.0 atomic percent (at.%) to 16.5 at.%. When the Sn content exceeds 16.5 at.%, a highly ordered intermetallic phase, δ, formed. The fracture stress (σf) and the critical stress for martensitic transformation (σMs) increases with an increase in Sn content. The mechanical properties as well as the superelasticity were greatly improved by a high cooling rate in the glass-coated melt spinning method. A bamboo-grained structure was formed in the Cu–Sn microwire with a Sn content of 16 at.% by annealing at 750 °C for 5 h before quenching in water. The results indicate that two opposite strategies of refining the grain size to the micrometer level, or increasing the grain size to a one dimensional size of specimen, e.g., the diameter of the wire, are both effective in improving the superelasticity of the Cu–Sn alloy.

Effect of pre-compression deformation on aging precipitation behavior and mechanical properties of Mg–5Sn alloy

The study aimed to investigate the impact of different aging time and the compression prior to aging on the precipitation behavior and mechanical properties of the Mg–5Sn(wt.%) alloy. The findings revealed that compression prior to aging significantly reduced the time required to reach peak aging and resulted in a higher peak hardness, reaching up to 63 H V after 5 h of aging. The pre-compression introduced dislocation densities of up to 1.916 × 1015/m2, creating more nucleation sites for precipitated phases. As a result, pre-compression aging led to an order of magnitude more precipitated phases compared to direct aging. Interestingly, the study also discovered that hardness and strength did not exhibit a traditional positive correlation. The maximum strength was not achieved when hardness reached its peak. The increased numbers of precipitated phases were closely associated with an increase in strength but did not always enhance the corresponding hardness. The deviation of the hardness along with the increased precipitated phases was mainly imputed to the softening of the precipitated phases themselves. These findings highlight the complex relationship between hardness, strength, and the microstructures of the Mg–5Sn alloy during pre-compression and aging treatment.

Kinetics of indium and indium–tin soldering materials in vacuum volatilization

Vacuum volatilization is a clean and efficient method for metal purification, alloy separation, and comprehensive recovery of secondary resources. The evaporation kinetics of In and In–Sn alloys were investigated to better understand the evaporation mechanism during the vacuum volatilization of In. The evaporation rates of the In and In–Sn alloys at 1173–1373 K and 5 Pa increased significantly with increasing temperature in accordance with the equation ω = e(a+b∙T). The evaporation rates at 1323 K and 5 Pa decreased with increasing crucible depth in accordance with the equation ω = a2+(a1-a2)/(1+e(h-b)/c). For In and In–Sn, the total mass-transfer coefficients of In were obtained at different temperatures and crucible depths. A theoretical kinetic model of In was established and limiting links were obtained vacuum volatilization of In and In–Sn.

Corrosion behaviours of a LaB6/TiC/TiB/ti composite in neutral or acidic electrolytes

LaB6/TiC/TiB was incorporated into a Ti–Al–Zr–Sn alloy to achieve an efficient improvement in acid-resistance. The incorporation of LaB6/TiC/TiB deteriorated the performance of the passive layer, but impeded the penetration of the corrosive medium into Ti matrix. The incorporation of the conductive reinforcements promoted galvanic corrosion, leading to a decrease in barrier effect of the passive film. Delayed passivation in less aggressive media was achieved by controlling the formation and growth of corrosion pits. The distribution of LaB6/TiC/TiB determined the corrosion properties after complete failure of the passive layer. An appropriate approach for enhancing the acid-resistance of Ti-based materials was suggested.

Theoretical Investigation of Half-metallicity and Pressure-induced Half-metallic Band Gap in Half Heusler RuMnZ (Z = Si, Ge, Sn, P, As, Sb, Se, and Te) Alloys

Theoretical Investigation of Half-metallicity and Pressure-induced Half-metallic Band Gap in Half Heusler RuMnZ (Z = Si, Ge, Sn, P, As, Sb, Se, and Te) Alloys

Low-dislocation-density ultrafine lamellar structure buffering triples ductility in Cu-8wt.%Sn alloy treated by rotary swaging and appropriate annealing

Breaking the strength-ductility trade-off in metal materials has always been a prominent topic in materials science. Here, we proposed a novel strategy of combining rotary swaging (RS) with appropriate annealing to construct an ultrafine lamellar structure with low dislocation density in Cu-8wt.% Sn alloy. This unique anisotropic structure achieves triple ductility without compromising strength compared with the traditional cold rolling process. Results show that the lamellar structure composed of alternating ultrafine-grained α-Cu and brittle Sn-rich phases can be significantly refined by RS, which can weaken stress concentration and thus reduce microcrack nucleation during tensile deformation. The lamellar ultrafine-grained α-Cu with low dislocation density has excellent strain hardening ability, which can effectively mediate deformation, and resist crack propagation and coalescence, thereby enhancing the ductility of materials. As a deformation method with industrial application capability, RS can construct a novel lamellar structure to overcome the strength-ductility dilemma, which deserves attention in materials science.

First-Principles Study of the Effect of Sn Content on the Structural, Elastic, and Electronic Properties of Cu–Sn Alloys

In order to explore the mechanism of the influence of Sn contents on the relevant properties of Cu–Sn alloys, the structure, elasticity, electronic, and thermal properties of Cu–Sn alloys doped with different proportions of Sn (3.125 at%, 6.25 at%, and 9.375 at%) were established using the first-principles calculation based on density functional theory. Firstly, their lattice constants and Sn concentration comply with Vegard’s Law. From the mixing enthalpy, it can be seen that Sn atoms can be firmly dissolved in the Cu matrix, and the structure is most stable when the Sn content is 3.125 at%. In addition, the introduction of mismatch strain characterized their solid solution strengthening effect. The elastic and electronic properties showed that when the Sn content is 6.25 at%, the Cu–Sn alloy has the best plasticity and the highest elastic anisotropy; when the Sn content is 3.125 at%, the Cu–Sn alloy is the most stable and has stronger bulk and shear modulus, which was mainly due to a stronger Cu-Cu covalent bond. Finally, the Debye temperature, thermal conductivity, and melting point were calculated. It is estimated that the thermal conductivity of Cu–Sn alloy is relatively good when the Sn content is low.

Revealing the role of Sn in NiSn for enhancing hydrogen evolution performance by density functional theory

Doping Sn into transition metal Ni can gain an enhanced hydrogen evolution performance. Optimizing H binding free energy (ΔGH) is considered as the main function of Sn. However, the detailed action mechanism of Sn in NiSn catalyst is still ambiguous. Herein, the functional role of Sn in NiSn was systematically inspected using density functional theory (DFT) method. The difference site Ni of Ni slab was replaced by Sn to build NiSn with the difference distribution of Sn. The calculations about the barrier of H2O dissociation and ΔGH show that surface Ni in NiSn is the main active site for catalyzing the hydrogen evolution reaction (HER) and the distribution of Sn in NiSn alloy directly decides the main role of Sn in promoting HER. Only replacing surface Ni with Sn, the main role of Sn is to reduce the adsorption of H and promote the H desorption step of HER. When Sn locates at sub-surface or surface and sub-surface Sn exist simultaneously, ΔGH on NiSn has no reduction and accelerating the H2O dissociation is the main function of Sn.

Nanophase transformation and strengthening - Toughening mechanism of the Cu–15Ni–8Sn alloy during aging

The Cu–15Ni–8Sn alloy ingot was prepared in the medium-frequency induction melting furnace. The hot extruded alloy was treated by solid solution at 840 °C for 60 min and aging at 400 °C for different times (0 miñ480 min). The effect of aging time on the evolution of the nanophase of Cu–15Ni–8Sn alloy and the strengthening-toughening mechanism were studied. The results show that at the beginning of aging, the alloy undergoes spinodal decomposition, the wavelength of the modulated structure is approximately 3∼7 nm, the ordered phase transformation of D022 and L12 occurs simultaneously, and the ordered phase size is approximately 5 nm. With the extension of aging time, the modulated structure became coarser, and the wavelength of the modulated structure increased to 5–9 nm. At the same time, the D022 ordered phase changed to the L12 ordered phase, and a continuous distribution of elliptical discontinuous precipitation appeared at the grain boundary. The ratio of the long and short axes of the discontinuous precipitation was approximately 4.7. In the late aging period, the D022 ordered phase was basically transformed into the L12 ordered phase, and discontinuous precipitation, which is incompatible with the matrix, extended into the crystal. After 120 min of aging at 400 °C, the hardness, strength, and elongation of the alloy are 105.4 HRB, 839.8 MPa and 9.6 %, respectively. The peak-aging states D022 and L12 coexist in an orderly phase at the nanoscale, and this nanoscale strengthening phase is completely integrated with the matrix, which improves the strength and toughness of the alloy. The research results can provide support for the development of high-performance copper alloys in the ocean.

An analytical model for calculating tie-line critical temperature in ternary immiscible alloys

An analytical model for calculating the tie-line critical temperature (TtC) in ternary immiscible alloys is proposed in this study. The results of the TtC for Al–Pb–Sn and Al–Bi–Sn alloys calculated by using the proposed model show a favorable agreement with the results obtained from the CALPHAD method and the experimental data, which verifies the correctness of the model. Based on the proposed model, the tie-line critical temperatures of several alloy systems, such as Al–In–Pb and Al–Bi–Pb, are calculated. The characteristics of the tie-lines in the ternary immiscible system are analyzed and discussed. The results indicate that ternary immiscible alloys can be divided into two types according to their characteristics of the tie-lines. For type I, the tie-line is nearly parallel to the edge binary system. For type II, there is a certain or large angle between the tie-line and the edge binary system. The relationship between the parameters for representing the tie-line equation and the critical point composition (xC) is determined by fitting the linear and secondary polynomial functions.

A Comparative Analysis of the Influence of Welding Current on Microstructure and Mechanical Properties in TIG Welded Ti5Al2.5Sn Alloy

Tungsten inert gas (TIG) welding was performed on a 1.6 mm thick Ti5Al2.5Sn alloy sheet to analyze the influence of welding current on the resultant microstructure and mechanical properties in the weldments. Fusion zone (FZ) width was observed to increase with increasing the welding current. The heat-affected zone (HAZ) showed acicular α, primary α and α' martensite phases depending upon the cooling rate. FZ was comprised of α´ martensite at the high cooling rate, acicular α at a low cooling rate and some retained β. The ultimate tensile strength (UTS), notch tensile strength (NTS) and impact toughness in all the weldments increased from 754 MPa to 810 MPa, 703 MPa to 785 MPa, and 2.3 J to 3.3 J, respectively, by increasing the welding current. However, percentage elongation decreased from 10% to 6.5% by increasing the welding current from 12 A to 18 A. Moreover, the impact toughness value was observed to increase by increasing welding current owing to the formation of a higher proportion in acicular α, α' martensite phases within the FZ. Furthermore, higher microhardness was achieved at higher currents.