Raw materials for preparing the alloys, pure tin (99.5 wt%), pure zinc (99.5 wt%), pure copper (99.5 wt%), pure silver (99.5 wt%), and pure antimony (99.5 wt%) are available in the local market. At first, the master alloy Sn–10Cu is prepared. The calculated amount of tin and copper is weighted. Subsequently, copper is put in a graphite crucible and heated to 11,00˚C in an electric melting furnace for ten minutes. Tin is added to the copper after it has melted, and the temperature stays the same until the melting is complete. The liquid solder alloy was cast in a 250 mm 10 mm 10 mm cast iron mold that had been warmed to 300˚C before cooling in the air. Every solder is poured into the form of an ingot that is rectangular. The melt was stirred to achieve homogeneity prior to casting. To eliminate micro-segregation effects, the as-cast alloys are annealed for 60 minutes at 150˚C, then cooled in a furnace. To prepare the quinary alloys, the calculated amounts of master alloy, tin, zinc, silver, and antimony are taken. Ten minutes at 430˚C in a muffle furnace are used to melt the master alloy, tin, and zinc contained in a clay graphite crucible. Subsequently, the crucible is filled with additional alloying components, such as antimony and silver, and left to reach 500˚C for 20 minutes. A 250 mm × 10 mm 10 mm cast iron mold that had been preheated to 300˚C was used to metal cast the liquid solder alloy, which was then allowed to cool. Before casting, the melt was stirred to make it homogeneous. Following a 60-minute annealing process at 150˚C, the as-cast alloys are cooled in the furnace. As-cast alloys were then sectioned and polished to prepare for characterization.

Microhardness tests were conducted using a Vickers microhardness tester. For microhardness testing, a flat and smooth surface is necessary. To obtain a smooth and flat surface for hardness tests, proper grinding and polishing are necessary. Therefore, samples were appropriately polished before indentation. To create a clear indentation for the microhardness test, the polished samples were inserted into the machine. The samples were studied for microhardness with the HMV-2T, Shimadzu Co., Japan, Vickers Microhardness Tester. The applied load was 50 g for 10 seconds. Each alloy was subjected to five room-temperature indentations to determine the average value. The standard deviation was also calculated. The values of microhardness were calculated from the following equation:

$\text{HV}=1.854\frac{F}{d^2}$ (1)

where, HV = Vickers hardness Number, F = applied load measured in kilogram-force, and d = arithmetic mean of the two diagonal lengths (mm) of indentation.

The tensile test is performed in a Universal Testing Machine (brand: Hounsfield, SR. No. H10KS-0572) at the cross-head speed of 2 mm/min, 10 mm/min, and 100 mm/min which is equal to the nominal strain rate of 4.17 × 10⁻³ s⁻¹, 20.85 × 10⁻³ s⁻¹, and 208.5 × 10⁻³ s⁻¹. Up until the specimen fails, the test is conducted at room temperature. Here are representative test curves for one sample of each alloy; test curves for the other samples, which showed comparable form and appearance, are not provided. The test is performed for the same three alloys, and the average of these results is taken as the test result for the corresponding alloy. The dimensions of the samples are gauge length 8 mm, thickness 2 mm, and width 3 mm as shown in Figure 1 .

A digital electrical conductivity meter (Technofour, type 979, India) is used to measure the electrical conductivity of the alloys in % I.A.C.S. (International Annealed Copper Standard). A hand-held probe is used to take the readings right away. Eddy currents at a set frequency are induced in the test portion when the probe is positioned on its flat surface. Specimens’ electrical conductivity is directly correlated with the electrical impedance of the test probe, which is impacted by these currents [43] . With an accuracy of ±1% I.A.C.S., the conductivity of the test sample is expressed as a percentage on a digital display upon detection and processing of the change in probe impedance.

The uniformity in the microstructure of a material has a great influence on its mechanical properties. Microscopic analysis of the prepared samples is carried out to know how the different phases are distributed in the alloys. The microstructure of the alloys is analyzed with a scanning electron microscope (Model: JOEL JSM-7600F). The SEM micrograph is presented in Figure 2 . The microstructure of the alloys has a brighter area (β-Sn) and a darker area (IMC).

The intermetallic compound phases are distributed in the Sn matrix with irregular shapes. Due to the addition of different amounts of multi-alloying elements simultaneously, the Zn-rich phase disappears, and different complex-shaped intermetallic compounds form and disperse in the β-Sn matrix. XRD data indicates that as the amount of alloying element increases, the crystallite size increases, and the dislocation density decreases.

The X-ray diffractometry (XRD) patterns of the quinary alloys are shown in Figure 3 . Analyzing the patterns, it is observed that all the alloys have Sn (tetragonal), Sb₃₀Zn_38.41 (hexagonal), and Sb₃₀Zn_38.45 (hexagonal) phases in common.

Moreover, alloys A-1 and A-2 have the phase Ag₃Sn (orthorhombic). Alloys A-2 and A-3 have the Cu₃Sn (orthorhombic) phase. Moreover A-1 and A-3 have the Cu₆Sn₅ (hexagonal), and AgZn₃ (hexagonal) phases. The intermetallic Ag₃Sn is a brittle phase with low plasticity, affecting the solder joints, mechanical properties, and thermal fatigue [44] [45] . Phases were confirmed with the analysis of the software X’Pert High Score Plus.

A substance’s ability to withstand localized plastic deformation brought on by abrasion or mechanical indentation is measured by its hardness. The microstructure of a material influences the movement of dislocations, which in turn influences the material’s hardness. A strong dependence of the Sn-based solder alloys’ hardness on the alloying elements is seen [46] . The microhardness measurement can identify the microstructural variations among the alloys. The microhardness of the Sn-9Zn eutectic alloy is found to decrease when 0.2 wt% and 0.4 wt% Ag, Cu, and Sb are added (alloy A-1, A-2). But when this amount is 0.6 wt%, the hardness is increased (alloy A-3) [47] . The weak spots that developed between the complex-shaped intermetallic compounds such as Sb₃₀Zn_38.45 (hexagonal), Sb₃₀Zn_38.41 (hexagonal), Cu₆Sn₅ (hexagonal), Ag₃Sn (orthorhombic), Cu₃Sn (orthorhombic), AgZn₃ (hexagonal), and the matrix caused the alloys’ hardness to diminish [48] [49] . The microhardness of the quinary alloys is shown in Figure 4 with error bars. It is observed that the microhardness of the quinary alloys increases with the contents of alloying elements.

Three types of alloys were used in the experiment. All test samples are annealed for one hour at 150˚C and an important influence is seen. The tensile test findings are summarized in Table 2 , where each datum represents the average of the three samples’ results. The tensile test was conducted at the strain rate of 4.17 × 10⁻³ s⁻¹, 20.85 × 10⁻³ s⁻¹, and 208.5 × 10⁻³ s⁻¹. Typical stress-strain curves are shown in Figure 5 . Test curves for a single sample of each alloy are shown here as typical test curves; those for the other samples, which showed comparable form and appearance, are not included. It is abundantly evident that the alloying element and strain rate influence stress levels and play a significant effect. Table 2 and Figure 6 show that the ultimate tensile strength (UTS) rises as the content of alloying elements and strain rate increases over the range under investigation at room temperature. The yield strength-strain rate curves of the alloys are plotted in Figure 7 . It is found that the yield strength of the alloys has a trend that is very similar to that of ultimate tensile strengths. Figure 8 displays the variation of % elongation of the different alloys. It was observed that the content of the alloying elements and strain rate for which the ultimate tensile strength is maximum, the ductility values of the alloys go through the minimum. From the

analysis of the obtained results, it is seen that the E-modulus of all the solder alloys raised with raising the content of the alloying elements as well as strain rates, which is by the previous results [50] [51] as shown in Figure 9 .

The capacity of a material to transport an electric current is known as its electrical conductivity. Because solder alloys are used to connect circuits on printed circuit boards, their electrical conductivity is crucial. It is seen that the simultaneous addition of Ag, Cu, and Sb (quinary alloy) reduces the electrical conductivity of the Sn-9Zn alloy ( Figure 10 ), increasing the solder alloys’ resistivity. The initial solvent lattice structure and the additional components dissolved in the alloy are destroyed, further destroying the lattice potential field’s periodicity. The alloys’ electrical conductivity decreases as a result of an increase in electron scattering. Precipitation of the added components from the Sn matrix occurs when their concentration in the solder exceeds a threshold value. The precipitation delayed the electrons’ travel by acting as a scattering center. Consequently, the electrical conductivity falls and the electrical resistivity rises [52] [53] .

Moreover, a drop in the number of effective electrons results from the interaction of the various complex-shaped intermetallic compounds with the additive elements, which in turn leads to a loss in electrical conductivity [54] . The conductivity of the solder connector in most microelectronics applications should be as high as possible to affect the electric circuit’s functionality. The conductivity data indicate that the electrical conductivity of the Sn-9Zn and the observed alloys differs by a tiny amount.