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The composition and structural modification of high-aluminum zinc alloys and high-zinc aluminum alloys influence their wear properties and structural stability. The work described has been aimed at improving properties of the sand-cast Al-Zn-based foundry alloys, particularly their ductility and dimensional stability, by melt inoculation and/or change of chemical composition. In a series of studies, high-aluminum Zn-(25-26) wt.% Al-(1-2.5) wt.% Cu and high-zinc Al-(27-30) wt.% Zn-(1.5-2.5) wt.% Cu alloys have been doped with different levels of added Ti and Mn. The alloys’ structure and mechanical properties have been studied using scanning electron microscopy (SEM), light microscopy (LM), dilatometry and pin-on-disk wear measurements. A small addition of Ti introduced with Zn-4Ti master alloy leads to significant grain refinement of the high-aluminum zinc alloys. A small addition of Ti introduced with Al-3Ti-0.15C master alloy leads to significant grain refinement of the high-zinc aluminum alloys. In the ternary alloys, partially replacing Cu with Ti and/or Mn allows dimensional changes to be reduced while preserving good wear properties.

Experimental and theoretical design on thermal and structural properties of Cu-Zn-Al alloys are established. As such, from an experimental point of view, differential thermal analysis has been performed with the help of a DSC Netzsch STA 449 F1 Jupiter calorimeter with high levels of sensitivity, and the structural analysis has been accomplished through X-ray diffraction and SEM analysis. An unusual specific property for a metallic material has been discovered, which is known as “rubber-type behavior”, a characteristic determined by micro-structural changes. From the theoretical point of view, the thermal transfer in Cu-Zn-Al is presented by assimilating this alloy, both structurally and functionally, with a multifractal, situation in which the order–disorder transitions assimilated with thermal “dynamics” of Cu-Zn-Al, are mimed through transitions from non-multifractal to multifractal curves. In such a context, the thermal expansion velocity contains both the propagation speed of the phase transformation (be it a direct one: austenitic–martensitic transformation, or an indirect one: martensitic–austenitic transformation) and the thermal diffusion speed. Then, through self-modulations of the thermal field, the Cu-Zn-Al alloy will self-structure in channel-type or cellular-type thermal patterns, which can be linked to obtained experimental data. Consequently, since the thermal conductivity becomes a function of the observation scale, and heat transfer is modified to reflect the multifractal, non-differentiable paths in the material, it leads to anomalous diffusion and complex thermal behaviors.

Tensile experiments were conducted for Al-7.0Zn-2.5Mg-2.0Cu-0.1Zr-0.2Sc alloy in different aging states (18 h, 24 h, 36 h) with temperature environments including room temperature, −10 °C and −30 °C. Comparative studies were made on the evolution of the precipitate phase in alloys at three kinds of aging times and the evolution of tensile properties in alloys under different ambient temperatures. The findings showed that the precipitates in Al-7.0Zn-2.5Mg-2.0Cu-0.1Zr-0.2Sc alloy were mainly in the GP zone after the solution + aging treatment η’ phase, the secondary Al3 (Sc, Zr) phase and the θ’ (Al2Cu) phase. As the aging time was prolonged, the η’ phase gradually grew and the PFZ gradually widened. At the three test temperatures, the tensile strength (TS) and yield strength (YS) of the alloys both showed a trend of first increasing before decreasing with the extension of aging time, while the elongation (A) and section shrinkage (Z) showed a decreasing trend. As the test temperature decreased, the TS and YS of the alloys increased and the A and Z of the alloys decreased. At room temperature, alloys showed a ductile fracture mode, which changed to mixed ductile and brittle fracture with decreasing test temperature.

In this study, we fabricated a mechanical joining with spot friction-stirring between an aluminum alloy plate and an aluminum–zinc alloy-coated steel sheet; this was achieved by utilizing a conventional press-punching preprocess. In the preprocessing, a hot-dip 55% aluminum–zinc alloy-coated steel sheet was punched using a press and an inclined surface was generated at the wall of a punched hole due to shear droop. Subsequently, an A5083P-O aluminum alloy plate was positioned against it, and friction stirring was conducted on its rear surface. The hole was filled with the aluminum alloy to generate a mechanical interlock at the tilt of the wall. Further, we evaluated its cross tensile strength (CTS) and tensile shear strength (TSS) and obtained an average CTS and TSS of 368 kN and 1470 kN, respectively.

Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al−Zn alloys and Al−Zn−Cu alloys are being used as an alternative to the Zn−Al alloys for bearing applications. In this study, both binary Al−25Zn and Al−3Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350ºC for 8 h and then, the alloys were furnace-cooled to 50ºC. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L 9 orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise (S/N) ratio analysis, and specific wear rate (SWR) is the selected response. The “smaller-the-better” is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance (ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) images.

A new approach to solid-state pressure welding of Zn–22% Al aluminum–zinc alloy in vacuum at a temperature of 250°C under conditions of low-temperature superplasticity is proposed. An ultrafine equi-axial structure with an average size of both phases was obtained by annealing in an oven at 350°C followed by quenching in water. This treatment produces stable ultrafine grains of about 0.65 μm with a uniform distribution of Zn and Al grains. When welding high-height billets with pressure, barrel-like properties appear on the side surface of welded materials. It is shown that the sizing of the mold for pressure welding of cylindrical billets makes it possible to influence development of local flow and to provide the most favorable conditions of deformation by optimizing energy consumption for deformation in the zone of the welded joint. As a result of heating and precipitation, a joint superplastic deformation occurs and the main deformation is localized in the region of formation of the solid-phase joint, while most of the blanks are slightly deformed. Oxide films on the surfaces to be joined are broken by extrusion and removed by superplastic deformation in radial directions, and a new oxide-free layer appears on the surface of the workpieces to be welded. The welded area is formed due to the occurrence of metal bonds between the juvenile contacting surfaces of the welded workpieces. Mechanical tensile tests showed that the strength of the solid-phase joints was 90–95% of the ultimate strength of the base material.

The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.

The proportion of hardening and softening under plastic deformation at room temperature in metals and alloys of the Al – Zn system has been studied as dependent on the regime of preliminary heat treatment. The influence of the strain rate on the dependence of alloy hardness on the degree of plastic deformation is estimated.

Al–12Zn–3Mg–2.5Cu alloy was prepared using a liquid metallurgy route under the optimized conditions. A sample cut from the ingot was rolled non-isothermally from 400°C to 100°C in 100°C steps,with 15% reduction in thickness; it was then cold rolled isothermally at room temperature for 85% reduction. The cold-rolled alloys were characterized by electron microscopy,hardness test,and tensile test to elucidate their structural evolution and evaluate their mechanical behavior. In the results,the cast alloy consists of α-aluminum and various intermetallic compounds. These compounds are segregated along the grain boundaries,which makes the alloy difficult to roll at room temperature. The combined effect of non-isothermal step rolling and cold rolling results in the nano/microsized compounds distributed uniformly in the matrix. The hardness is substantially increased after rolling. This increase in hardness is attributed to the ultra-fine grain size,fine-scale intermetallic compounds,and structural defects(e.g.,dislocations,stacking faults,and sub-grains). The ultimate tensile strength of the rolled alloy is approximately 628 MPa with 7% ductility.

In this investigations, sliding wear performance of Al-25Zn based novel hybrid composites added with fixed weight percentage of graphite (3 wt.%) and varying weight percentage of silicon carbide (10, 20 and 30 wt.%) was investigated for various process factors such as specimen temperature, applied load, sliding speed and sliding distance using a pin on disc with EN24 disc as per Taguchi L16 array. For similar test conditions, the composite with 10 wt.% of silicon carbide shows the highest wear resistance and tensile strength; whereas the composite with 20 wt.% of SiC shows highest hardness. The specimen temperature is recognized as the dominating parameter for the sliding wear performance of the materials. Artificial Neural network and Regression model developed was found competent for the forecasting of wear performance. Confirmation experiment conducted with the optimum parameter combination also confirmed the accuracy of developed model. The observed wear mechanism is abrasion and adhesion. The major mechanisms of abrasive wear are recognized as ploughing, micro cutting and delamination.