Abstract:The strength and fracture toughness o f Al-Zn-M g-Cu-Ti(-Sn) alloys were investigated by performing tensile and plane strain fracture toughness (KIC) tests. Detailed observations with optical, scanning electron and transmission electron microscopy were conducted to analyze microstructure andfracture surfaces o f the alloys. The results revealed that addition o f Sn refined the solution-aging grain size o f matrix and reduced coarsening rate o f precipitate during aging. Narrower precipitation free zones and mo… Show more
“…At points (b) and (c), the Zn/Mg and the Mg/Sn ratios are approximately equal to 2:1 (Tables IIb and IIc). The atomic ratio Mg/Sn suggests that the composition of the particle at point (b) is MgZn 2 and Mg 2 Sn (point c), as reported by Ma et al 24 and Yan et al 68 To understand the nature of the two phases formed in the alloy, additional EDS and SEM analyses were carried out (Fig. 3).…”
Section: Resultsmentioning
confidence: 68%
“…Sn-containing alloy shows more irregular precipitation at the grain boundary and the magnification of the precipitate was mainly related to the diffusion of solute atoms. 68 This is may be due to the Sn low solid solubility in the aluminum matrix, which is recognized to be about 0.1% at a temperature of 600 °C and above. 69 Accordingly, it tends to form an interdendritic structure and to diffuse preferentially to the grain boundaries.…”
In this work, two aluminum alloys, Al-5Zn-0.5Sn and Al-5Zn-0.5Sn-2.6Mg, were prepared by melting in an induction furnace to be used as sacrificial anodes for cathodic protection of marine structures. The alloys are characterized by scanning electron microscopy mapping coupled to energy dispersive X-ray analysis, X-ray photoelectron spectroscopy and X-ray diffraction. Afterwards, the corrosion behavior was studied in 3 wt.% NaCl solution through immersion tests, potentiodynamic polarization, electrochemical impedance spectroscopy and weight-loss measurements. Results display that active dissolution of Al-5%Zn-0.5%Sn-2.6%Mg alloy and its quasi-uniform corrosion is associated with the major precipitates MgZn2 and Mg2Sn particles formed during the melting process. Galvanic coupling measurements over 45 d were carried out on both alloys. The sacrificial cathodic protection of both anodes was successful but the couple efficiency was greater for Al-Zn-Sn-Mg owing to its more negative corrosion potential and uniform dissolution.
“…At points (b) and (c), the Zn/Mg and the Mg/Sn ratios are approximately equal to 2:1 (Tables IIb and IIc). The atomic ratio Mg/Sn suggests that the composition of the particle at point (b) is MgZn 2 and Mg 2 Sn (point c), as reported by Ma et al 24 and Yan et al 68 To understand the nature of the two phases formed in the alloy, additional EDS and SEM analyses were carried out (Fig. 3).…”
Section: Resultsmentioning
confidence: 68%
“…Sn-containing alloy shows more irregular precipitation at the grain boundary and the magnification of the precipitate was mainly related to the diffusion of solute atoms. 68 This is may be due to the Sn low solid solubility in the aluminum matrix, which is recognized to be about 0.1% at a temperature of 600 °C and above. 69 Accordingly, it tends to form an interdendritic structure and to diffuse preferentially to the grain boundaries.…”
In this work, two aluminum alloys, Al-5Zn-0.5Sn and Al-5Zn-0.5Sn-2.6Mg, were prepared by melting in an induction furnace to be used as sacrificial anodes for cathodic protection of marine structures. The alloys are characterized by scanning electron microscopy mapping coupled to energy dispersive X-ray analysis, X-ray photoelectron spectroscopy and X-ray diffraction. Afterwards, the corrosion behavior was studied in 3 wt.% NaCl solution through immersion tests, potentiodynamic polarization, electrochemical impedance spectroscopy and weight-loss measurements. Results display that active dissolution of Al-5%Zn-0.5%Sn-2.6%Mg alloy and its quasi-uniform corrosion is associated with the major precipitates MgZn2 and Mg2Sn particles formed during the melting process. Galvanic coupling measurements over 45 d were carried out on both alloys. The sacrificial cathodic protection of both anodes was successful but the couple efficiency was greater for Al-Zn-Sn-Mg owing to its more negative corrosion potential and uniform dissolution.
“…However, the appearance of PFZs near the grain boundaries adversely effected the fatigue response of the peak aged sample. Therefore, PFZs may have detrimental influence, causing a negligible increase in the fatigue performance by increasing aging time (from 1 to 6 h) [19-21]. Figure 6 SEM micrographs from the fracture surfaces of UFG CuNi3Si1Mg after precipitation hardening at 450°C for (a) 1 h; (b) 6 h; (c) 12 h.…”
Section: Resultsmentioning
confidence: 99%
“…However, the appearance of PFZs near the grain boundaries adversely effected the fatigue response of the peak aged sample. Therefore, PFZs may have detrimental influence, causing a negligible increase in the fatigue performance by increasing aging time (from 1 to 6 h) [19][20][21].…”
This study evaluated the effects of shot peening (SP) for modifying the fatigue performance of ultrafine-grained CuNi3Si1Mg. Fatigue damage is possibly caused when electromechanical connectors are subjected to cyclic loading or high numbers of repeated plugging. The fatigue performance of the precipitation-hardened ultrafine-grained CuNi3Si1Mg was significantly enhanced from 325 MPa in the electropolished condition to 400 MPa after SP at an Almen intensity of 0.25 mmA. In the precipitation-hardened ultrafine-grained CuNi3Si1Mg, SP induced a high degree of work hardening and maximum compressive residual stress values on the surface layers, which resulted in a better fatigue performance than the electropolished counterpart. After SP, the dissolution of precipitates in the surface layers also improved fatigue performance by reduction in the negative effect of the surface precipitates.
“…Fig. 3a) shows a silver nanoparticle with a size of 30 nm, around which there are smaller phases corresponding to the MgZn 2 phase, this phase lead to the most significant improvement of mechanical properties in the Al 7075 alloy [15]. The shield of carbon that surrounds the silver nanoparticles avoids this to dissolve into the aluminum.…”
Nanostructured composites of the aluminum 7075 alloy and carbon-coated silver nanoparticles were synthetized by the mechanical milling technique using a high-energy mill SPEX 8000M; the powders generated were compacted, sintered and hot-extruded to produce 1 cm-diameter bars. The composites were then subjected to a wear test using a pin-on-disc device to validate the hypothesis that second phase-ductile nanometric particles homogenously distributed throughout the metalmatrix improve the wear resistance of the material. It was found that silver nanoparticles prevent the wear of the material by acting as an obstacle to dislocations movement during the plastic deformation of the contact surface, as well as a solid lubricant when these are separated from the metal-matrix.
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.
