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This study aims to investigate the chromium (Cr) effects on the microstructural, mechanical and thermal properties of melt-spun Sn-3.5Ag alloy.

Ternary melt-spun Sn-Ag-Cr alloys were investigated using X-ray diffractions, scanning electron microscope, dynamic resonance technique, instron machine, Vickers hardness tester and differential scanning calorimetry.

The results revealed that the Ag₃Sn intermetallic compound (IMC) and ß-Sn have been refined because of the hard inclusions’ (Cr atoms) effects, causing lattice distortion increasing these alloys. The tensile results of Sn_96.4-Ag_3.5-Cr_0.1 alloy showed an improvement in Young’s modulus more than 100 per cent (42.16 GPa), ultimate tensile strength (UTS) by 9.4 per cent (23.9 MPa), compared with the eutectic Sn-Ag alloy due to the high concentration of Ag₃Sn and their uniform distribution. Shortage in the internal friction (Q⁻¹) of about 54 per cent (45.1) and increase in Vickers hardness of about 7.4 per cent (142.1 MPa) were also noted. Hexagonal Ag₃Sn formation led to low toughness values compared to the eutectic Sn-Ag alloy, which may have resulted from the mismatching among hexagonal Ag₃Sn phase with orthorhombic Ag₃Sn and ß-Sn phases. Mechanically, the values of Young’s modulus have been increased, with increasing chromium content, whereas the UTS and toughness values have been decreased. The opposite of this trend appeared in Sn_95.8-Ag_3.5-Cr_0.7 alloy, which may have been due to high lattice distortion (ƹ = 16.5 × 10⁻⁴) compared to the other alloys. Increase in the melting temperature T_m, ΔH, C_p and ΔT was because of Ag₃Sn IMC formation. The low toughness of Sn₉₆-Ag_3.5-Cr_0.5 and Sn_95.8-Ag_3.5-Cr_0.7 (109.56 J/m³ and 35.66 J/m³), relatively high melting temperature Tm (223.22°C and 222.65°C) and low thermal conductivity and thermal diffusivity (32.651 w.m⁻¹.k⁻¹ and 0.314 m²/s) make them undesirable in the soldering process. The high UTS, high E, high thermal conductivity and diffusivity, low creep rate and low electrical resistivity, which have occurred with “0.1 Wt.%” of Cr, make this alloy desirable and reliable for soldering applications and electronic assembly.

This study provides chromium effects on the structure of the eutectic Sn-Ag rapidly solidified by melt-spinning technique. In this paper, the authors compared the elastic modulus of the melt-spun compositions, which have been resulted from the Static method with that have been resulted from the Dynamic method. This paper presents new improvements in mechanical and thermal performance.

This study aims to investigate the structural, mechanical, thermal and electrical properties of tin–silver–nickel (Sn-Ag-Ni) melt-spun solder alloys. So, it aims to improve the mechanical properties of the eutectic tin–silver (Sn-Ag) such as tensile strength, plasticity and creep resistance by adding different concentrations of Ni content.

Ternary melt-spun Sn-Ag-Ni alloys were investigated using x-ray diffractions, scanning electron microscope, dynamic resonance technique (DRT), Instron machine, Vickers hardness tester and differential scanning calorimetry.

The results revealed that the Ni additions 0.1, 0.3, 0.5, 0.7, 1, 3 and 5 Wt.% to the eutectic Sn-Ag melt-spun solder were added. The “0.3wt.%” of Ni was significantly improved its mechanical properties to efficiently serve under high strain rate applications. Moreover, the uniform distribution of Ag₃Sn intermetallic compound with “0.3wt.%” of Ni offered the potential benefits, such as high strength, good plasticity consequently and good mechanical performance through a lack of dislocations and microvoids. The tensile results showed improvement in 17.63 per cent tensile strength (26 MPa), 21 per cent toughness (1001 J/m³), 22.83 per cent critical shear stress (25.074 MPa) and 11 per cent thermal diffusivity (2.065 × 10⁻⁷ m²/s) when compared with the tensile strength (21.416 MPa), toughness (790 J/m³), critical shear stress (19.348 MPa) and thermal diffusivity (1.487 × 10⁻⁷ m²/s) of the eutectic Sn-Ag. Slight increments have been shown for the melting temperature of Sn_96.2-Ag_3.5-Ni_0.3 (222.62°C) and electrical resistivity to (1.612 × 10⁻⁷ Ω.m). It can be said that the eutectic Sn-Ag solder alloy has been mechanically improved with “0.3wt.%” of Ni to become a suitable alloy for high strain rate applications. The dislocation movement deformation mechanism (n = 4.5) without Ni additions changed to grain boundary sliding deformation mechanism (n = 3.5) with Ni additions. On the other hand, the elastic modulus, creep rate and strain rate sensitivity with “0.3wt.%” of Ni have been decreased. The optimum Ni-doped concentration is “0.7wt.%” of Ni in terms of refined microstructure, electrical resistivity, Young’s Modulus, bulk modulus, shear modulus, thermal diffusivity, maximum shear stress, tensile strength and average creep rate.

This study provides nickel effects on the structural of the eutectic Sn-Ag rapidly solidified by melt-spinning technique. In this paper, the authors have compared the elastic modulus of the melt-spun compositions which has been resulted from the tensile strength tester with these results from the DRT for the first time to best of the authors’ knowledge. This paper presents new improvements in mechanical and electrical performance.

This paper aims to summarise the effects of ZnO nanoparticles (0.1, 0.3, 0.5, 0.7 and 1.0 Wt.%) on the structure, mechanical, electrical and thermal stability of Sn–3.5Ag–0.5Cu (SAC355) solder alloys for high-performance applications.

The phase identification and morphology of the solders were studied using X-ray diffraction and scanning electron microscopy. Thermal parameters were investigated using differential scanning calorimetry. The elastic parameters such as Young's modulus (E) and internal friction (Q⁻¹) were investigated using the dynamic resonance technique, whereas the Vickers hardness (Hv) and creep indentation (n) were examined using a Vickers microhardness tester.

Microstructural analysis revealed that ZnO nanoparticles (NPs) were distributed uniformly throughout the Sn matrix. Furthermore, addition of 0.1, 0.3 and 0.7 Wt.% of ZnO NPs to the eutectic (SAC355) prevented crystallite size reduction, which increased the strength of the solder alloy. Mechanical parameters such as Young's modulus improved significantly at 0.1, 0.3 and 0.7 Wt.% ZnO NP contents compared to the ZnO-free alloy. This variation can be understood by considering the plastic deformation. The Vickers hardness value (Hv) increased to its maximum as the ZnO NP content increased to 0.5. A stress exponent value (n) of approximately two in most composite solder alloys suggested that grain boundary sliding was the dominant mechanism in this system. The electrical resistance (ρ) increased its maximum value at 0.5 Wt.% ZnO NPs content. The addition of ZnO NPs to plain (SAC355) solder alloys increased the melting temperature (T_m) by a few degrees.

Development of eutectic (SAC355) lead-free solder doped with ZnO NPs use for electronic packaging.

This study aims to investigate the effect of a small amount of TiO₂ NPs addition on the microstructure, thermal, mechanical and electrical properties of environmentally friendly eutectic (SAC355)_100-x(TiO₂)_x (x = 0.1, 0.3, 0.5, 0.7 and 1 wt.%) solder alloys.

Mechanical, thermal and electrical properties and microstructure conditions are taken into major consideration in any study of materials containing nanoparticles. Dynamic resonance technique, X-ray diffraction and scanning electron microscopy were carried out to study stiffness, identification of the phases and the morphology features of the solder. Structure and microstructure analysis indicated that the presence of rhombohedral β–Sn phase in addition to orthorhombic intermetallic compound (IMC) Ag₃Sn and Cu₃Sn phase dispersed in Sn matrix. In addition, the results showed that TiO₂ NPs addition at a small trace amount into SAC355 system reduces and improves the particle size of both rhombohedral β–Sn and orthorhombic IMC Ag₃Sn and Cu₃Sn. The interstitial dispersion of TiO₂ NPs at grain boundaries resulted in Ag₃Sn being more uniform needle-like, which is distributed in the β–Sn matrix. The fine and uniform microstructure leads to improvement of mechanical strength.

Some important conclusions are summarized as follows: microstructure investigations revealed that the addition of TiO₂ NPs particles to eutectic SAC355 inhibited in reducing and refines the crystallite size as well as the Ag₃Sn IMC, which reinforced the strength of plain solder alloy. The mechanical properties values such as Young’s modulus and Vickers microhardness of SAC355 solder alloy can be significantly improved by adding a trace amount of TiO₂ NPs compared with plain solder because of the existence of appropriate volume fraction of Ag₃Sn IMC. The results show that the best creep resistance is obtained when the addition of 0.3 wt.% of TiO₂ NPs is compared to plain solder. TiO₂ NPs addition could increase the melting temperature, compared with plain solder. All results showed that TiO₂ NPs addition is an effective method to enhance new solder joints.

New solder alloys.

Development of TiO₂ NPs-doped eutectic SAC355 lead-free solder for electronic packaging.