“…Therefore, the above results indicate that the reaction layer of the Al/Al bimetallic composites consists of the η -Zn, α -Al rich, α + η eutectoid, and primary silicon phases. Figure 3 (a, e, i) Magnified SEM micrographs of the interface of the Al/Al bimetallic composites corresponding to Figure 2(b–d), respectively; (b–d, f–h, j–l) EDS maps corresponding to (a, e, i), respectively. Figure 4 Al-Zn phase diagram [31–33]. …”
A novel method named the lost foam casting (LFC) liquid–liquid compound process with a Zn interlayer was proposed to prepare the Al/Al bimetallic composites, and the microstructure of the Al/Al bimetallic composites was investigated in the present work. The results showed that the Al/Al bimetallic composites were successfully produced using the novel process. The Zn interlayer prevented different liquid metals from directly mixing. A uniform and compact metallurgical interface was obtained between the Al and the A356 aluminium alloy, which consisted of the η-Zn, α-Al rich, α + η eutectoid, and primary silicon phases. The microhardness of the interface layer was significantly higher in comparison with those of the Al and A356 matrixes.
“…Therefore, the above results indicate that the reaction layer of the Al/Al bimetallic composites consists of the η -Zn, α -Al rich, α + η eutectoid, and primary silicon phases. Figure 3 (a, e, i) Magnified SEM micrographs of the interface of the Al/Al bimetallic composites corresponding to Figure 2(b–d), respectively; (b–d, f–h, j–l) EDS maps corresponding to (a, e, i), respectively. Figure 4 Al-Zn phase diagram [31–33]. …”
A novel method named the lost foam casting (LFC) liquid–liquid compound process with a Zn interlayer was proposed to prepare the Al/Al bimetallic composites, and the microstructure of the Al/Al bimetallic composites was investigated in the present work. The results showed that the Al/Al bimetallic composites were successfully produced using the novel process. The Zn interlayer prevented different liquid metals from directly mixing. A uniform and compact metallurgical interface was obtained between the Al and the A356 aluminium alloy, which consisted of the η-Zn, α-Al rich, α + η eutectoid, and primary silicon phases. The microhardness of the interface layer was significantly higher in comparison with those of the Al and A356 matrixes.
“…After an annealing time of 3 min, the microstructure of Al-10Zn consists mainly of (α-Al) and (α+η) phases and an (α+η)-rich phase. The amounts of the (α+η) phase and (α+η)rich phase gradually increased by comparing the microstructure of the extruded stage and rapidly annealed state [8]. The results indicate that the solid solubility of Zn that diffuses into the lattice to form a solid solution gradually increases with increasing annealing time.…”
Al and Zn powders in the ratio of 9:1 (wt. %) were alloyed into rods with a dense structure by using the continuous extrusion technique. To promote metallurgical bonding of heterogeneous elements, the microstructures of these rods with different holding times (1, 3, and 5 minutes) at the same annealing temperature were investigated. With the increase of annealing time, the microstructure consisted mainly of (α-Al) and (α+η) phases and an (α+η)-rich phase. The solid solubility of Zn into Al also gradually increased. The calculated X-ray diffraction (XRD) data showed that the lattice parameter of Al decreased to 4.04793 Å after 5 minutes of annealing, which was decreased by 0.062% compared to the lattice parameter of Al in the powder state. The microscopic stress and dislocation density of Al were increased by 0.27% and 12.52 × 1014 m-2 respectively after extrusion, and the microscopic deformation and dislocation density were decreased to 0.2% and 8.71 × 1014 m-2 respectively after being annealed for 5 minutes. The dislocation density and lattice distortion after annealing gradually decreased with increasing annealing time, and the scanning electron microscopy (SEM) results indicated that the mass percentage of Zn increased with increasing annealing time.
“…No intermetallic compounds are formed in the Al-Zn binary system due to the very weak chemical interaction between Al and Zn [22]. Instead, Zn forms very fine nanoprecipitates in the Al matrix and complex microstructures consisting of eutectoid lamellae (α-Al and η-Zn) and the Zn phase in the vicinity of the grain boundaries [19,23,24]. This complex microstructure is more developed as the amount of Zn increases such that the mechanical strength of high-Zn Al-based alloys is correspondingly enhanced according to the amount of Zn.…”
We investigate the effect of the natural age-hardening response of the Al-20Zn-3Cu alloy with natural aging times up to 12 months. The ultimate tensile strength of the Al-20Zn-3Cu alloy is drastically enhanced from 308 to 320 MPa after 2 months and from 320 to 346 MPa after 9 months. Then, natural age hardening becomes saturated after 9 months. A microstructural investigation reveals that the natural age-hardening mechanism is mainly induced by the diffusion of the Zn element. First, a rapid decrease in the volume fraction of the eutectoid lamellae (α-Al+η-Zn) is observed at the early stage of natural aging, leading to an increase in the tensile strength. This originates from the relatively high diffusivity of Zn due to its low melting temperature. Then, the diffusion of Zn into the Al matrix induces clusters of solute atoms that enhance the growth rate of the nanoprecipitates formed in the Al matrix. As a consequence, the tensile strength of the natural-aged Al-20Zn-3Cu alloy increases drastically after 9 months, whereas the ductility is significantly degraded.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
