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Microalloying has been an important method in aluminum alloy development for decades. Large number of papers have shown that the addition of trace element Erbium (Er) can effectively improve the comprehensive properties of aluminum alloys. Similar with the trace element Scandium (Sc), addition of trace element Er in aluminum alloys could form nano-sized L12-ordered Al3Er precipitates, which was coherent with the Al matrix. However, the dispersion precipitation strengthening effect of Al3Er was more significant than that of Al3Sc, at the same atomic content. In the case of the addition of both Er and Zr, core–shell-structured Al3(Er, Zr) precipitates formed instead of Al3Er precipitates. Those thermally-stable nanosized precipitates could significantly refine the grain size, retard the recrystallization, improve the mechanical properties and corrosion resistance. This paper reviewed several typical Er-containing microalloyed commercial aluminum alloys, like 2xxx (Al–Cu) alloys, 4xxx (Al–Si) alloys, 5xxx (Al–Mg) alloys, 7xxx (Al–Zn–Mg–Cu) alloys, as well as selective laser melting aluminum alloys. [ABSTRACT FROM AUTHOR]

The precipitation and intergranular corrosion (IGC) behavior of Al–1.0Mg–0.6Si–Cu (wt.%) alloys with the addition of Cu ranged from 0.3 to 0.6 wt.% were investigated by optical microscope and transmission electron microscopy. The results indicated that the Cu addition significantly improves the hardness of the alloys during under-aging progress by accelerating the precipitation of GP zones. The addition of Cu has changed the composition of precipitation and facilitated the formation of β′′-Mg5Si6 precipitates with high density and fine distribution. When the Cu content is added to 0.6 wt.%, the type of precipitation has changed. In addition to the needle-shaped β′′ phase, a new-plate Q′ phase precipitated during peak-aging conditions. The 0.6 wt.% Cu alloy shows superior strength with tensile yield strength of 328 MPa, ultimate tensile strength of 368 MPa, and elongation of 16.0%. However, the IGC resistance decreased with the Cu content increasing from 0.3 to 0.6 wt.%, which mainly resulted from the segregation of Cu elements and the formation of continuous Q′ precipitates at the grain boundaries. [ABSTRACT FROM AUTHOR]

The healing kinetics of nanometer-scale voids in Al-Mg-Er and Al-Mg-Zn-Er alloy systems were investigated with a combination of in situ transmission electron microscopy and electron tomography at different temperatures. Mg was observed completely healing the voids, which were then rejuvenated to the alloy composition with further aging, in the Al-Mg-Er alloy. On the contrary, MgZn intermetallic compound was formed in voids in the Al-Mg-Zn-Er alloy, which leads to complete filling of the voids but not rejuvenation for the material. For voids with different geometrical aspects, different evolution processes were observed, which are related to the competition between bulk and surface diffusion of the alloys. For voids with a large size difference in their two ends, a viscous flow of surface atoms can be directly observed with in situ electron microscopy, when the size of one end becomes less than tens of nanometers. [ABSTRACT FROM AUTHOR]

A method was developed for the determination of cadmium(II) by ligand-less solid phase extraction that is based on the direct retention of Cd(II) in a mini-column filled with a silica gel modified with an amino-functionalized ionic liquid. The effects of pH, sample volume and its flow rate, eluent concentration and its volume, the flow rate of eluent, and of potential interferences on extraction and desorption were optimized. Following its determination by electrothermal atomic absorption spectrometry, the detection limit for Cd(II) is 8.9 ng L, and the relative standard deviation is 2.3 % (at 1.0 ng mL; for n = 5). The method was applied to the analysis of Cd(II) in a certified reference material (laver; GBW10023), and the recoveries ranged from 97.0 to104.0 % [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A simple and rapid method based on dispersive liquid-liquid microextraction with room temperature ionic liquid 1,3-dibutylimidazolium hexafluorophosophate ([BBIM][PF]) coupled to flame atomic absorption spectrometry was developed for the speciation of Mn(II)/Mn(VII) in tea samples. The main factors affecting dispersive liquid-liquid microextraction were investigated in detail. Mn(II) and total manganese [Mn(II)+Mn(VII)] were quantitatively extracted after adjusting aqueous sample solution to pH 10.0 and 7.0, respectively. Mn(VII) was calculated by subtraction of Mn(II) from total manganese. Under the optimized conditions, the limits of detection (3 σ) for Mn(II) and Mn(VII) were 0.26 and 1.86 ng/mL, and their relative standard deviations were 2.6 and 4.8 % ( n = 7, c = 25.00 ng/mL). The proposed method was validated by the determination of Mn(II) and Mn(VII) in the certified reference material [GBW(E)08513] of tea sample and different local tea samples with satisfactory results. [ABSTRACT FROM AUTHOR]

A simple method based on cloud point extraction (CPE) separation and inductively coupled plasma mass spectrometry (ICP-MS) detection was proposed for the determination of species of aqueous-exchangeable selenium and unaqueous-exchangeable selenium. When the system temperature is higher than the cloud point extraction temperature (CPT) of the surfactant of p-octyl polyethyleneglycolphenyl ether (Triton X-100), the complex of selenium(IV)-diethyl-dithiocarbamate (DDTC) (total selenium and aqueous-exchangeable selenium) could be extracted into the surfactant-rich phase, an in situ separation of selenium(IV) could be realized. Unaqueous-exchangeable selenium concentration was obtained by respectively subtracting aqueous-exchangeable selenium from the total selenium. The chemical variables affecting the CPE were optimized. Under the optimized conditions, the limit of detection (LOD) and the relative standard deviations (RSD) was 0.10 ng/mL and 3.2% ( c = 10.0 ng/mL, n = 11), respectively, for Se(IV). The proposed method was applied to the speciation of aqueous-exchangeable and unaqueous-exchangeable selenium in tea samples with satisfactory results. [ABSTRACT FROM AUTHOR]

This work discusses the characterization of the hot cracking resistance and mechanical properties of Al-Cu-Mn-Cd (-Er-Zr) alloy using the “constrained rod casting” method and mechanical tensile testing. Analysis of the Al-Cu-Mn-Cd (-Er-Zr) alloy's microstructure was conducted using testing methods such as optical microscopy, scanning electron microscopy, transmission electron microscopy, and others. The results indicate that alloys with the addition of Er and Zr exhibit higher resistance to hot cracking compared to alloys without Er and Zr. The Er and Zrmainly refine the grain size by increasing the degree of ingredient supercooling, while simultaneously improving the alloy’s resistance to hot cracking by increasing the proportion of eutectic structure. The addition of Er and Zr results in grain size refinement and a reduction in the secondary dendrite arm spacing. The average grain sizes of alloys containing Er and Zr, and alloys without Er and Zr, are 138.43 μm and 151 μm, respectively. The average spacing of secondary dendrite arms is 21 μm and 31 μm, respectively. The average tensile strengths of alloys treated with T6 heat treatment are 500 MPa and 474 MPa, respectively. During the heat treatment process of the alloy containing Er and Zr, the formation of the Al3(Er, Zr) phase provides non-uniform nucleation sites for the θ′ phase, thereby reducing the size of the θ′ phase and consequently enhancing the strength of the alloy. [ABSTRACT FROM AUTHOR]