Effects Of Er Addition Research Articles

Effect of Er addition on the oxidation behavior of Mg-4Al-0.2Mn alloy at high temperatures

Isothermal oxidation experiments in the range of 450–525 °C were carried out to investigate the effect of different Er contents (0, 0.35, 0.96 and 2.27 wt.%) on the oxidation resistance of Mg-4Al-0.2Mn alloys. The addition of Er extended the incubation period of the alloys. The best oxidation resistance of the alloy was obtained with the Er content of 0.96 wt.%. This is due to (i) the formation of a stable oxide film containing Er2O3 on the surface of the alloy, which inhibits further oxidation of the substrate, and (ii) the improvement of the thermal stability of the substrate. The oxidation kinetics of these alloys at elevated temperatures follow parabolic, linear, and superlinear laws.

Effect of Er addition on the microstructure, mechanical properties and corrosion behaviour of Al-Zn-Mg-Cu alloy manufactured by laser powder bed fusion

The purpose of this study is to gain a deeper understanding of the effects of rare-earth element Er on the microstructure and properties of Al-Zn-Mg-Cu alloy manufactured by laser powder bed fusion (LPBF). Compared with the as-printed Al-Zn-Mg-Cu alloy without Er addition, the as-printed Al-Zn-Mg-Cu-Er alloy with a bimodal grain structure had finer cellular structures and denser precipitation phases, which significantly improved the alloy's mechanical and corrosion resistance properties. The tensile strength of the as-printed Al-Zn-Mg-Cu-Er alloy was 383 MPa, which is 137 MPa higher than that of the as-printed Al-Zn-Mg-Cu alloy without Er addition. It was intended to use T6 heat treatment process to further regulate the mechanical properties of the as-printed alloy, but the formation of Si-rich hard and brittle eutectic phases with sizes of 2–5 μm in the matrix resulted in a decrease in the strength of the alloy, which is contrary to the traditional 7xxx aluminum alloys. Besides, the addition of Er element improved the alloy's corrosion resistance by decreasing the corrosion current density and raising the intergranular corrosion (IGC) resistance, and the maximum intergranular corrosion depth decreased from 174 µm to 68 µm after Er addition.

Effects of Er addition on the hot deformation behavior and microstructure evolution of AZ31 alloy

AZ31 magnesium alloys typically have poor room temperature ductility after initial deformation. To address this disadvantage, rare earth element Er is introduced to regulate the structure, weaken texture, and promote non-basal slip to achieve plasticization. In this study, the deformation behavior and microstructure evolution during the hot compression process of Er added AZ31 alloy were systematically investigated. Hot compression stress-strain curves showed that the addition of Er reduced the deformation resistance. The constitutive equation and processing map were established. By combining the processing map with the microstructure analysis and texture evolution, an optimal processing area was determined to be 350–400 °C at a strain rate of 0.01 s−1. The influence of Er addition on the twinning behavior, recrystallization mechanism, and slip system of the AZ31 alloy were discussed. During the deformation process, the twinning behavior violates the maximum SF criterion, which is related to severe local stress. Continuous dynamic recrystallization, discontinuous dynamic recrystallization, and twinning induced recrystallization are all detected in the alloy. Through the in-grain misorientation axis and transmission electron microscopy, it can be confirmed that the addition of Er promoted the occurrence of pyramidal <c+a> slip. This is related to the modification of stacking fault energy by Er and the hindrance effect of the second phase containing Er on the basal dislocation.

Influence of erbium addition on microstructure and performances of AlSi10Mg alloy prepared by selective laser melting

The effect of rare earth addition on the microstructure and mechanical performances of as-cast and wrought Al alloys has been attracting increasing attention recently. Rare earth addition has great potential in modifying the structure and improving the properties of materials. However, there are currently few reports about the effect of rare earth addition on the microstructure and performances of Al alloys prepared via selective laser melting. Here, AlSi10Mg alloys were manufactured using selective laser melting, and the effect of Er addition was investigated. The results indicate that Er addition leads to α-Al refinement and modifies the minority Si phase. The formation of the Al3Er phase induced by Er addition enhances the strength of the material. Modification of the Si phase also increases ductility. This strategy can help improve the mechanical performance of aluminum alloys prepared via selective laser melting.

Effects of Er addition and cooling rate on the corrosion resistance of Zn-5Al alloys

Galfan (Zn-5Al-RE) coating is widely used in high-strength steel wires. The effects of cooling rate and the adulteration of erbium (Er) on the microstructure and corrosion resistance of Zn-5Al alloys were investigated in this study. The results show that the Zn-5Al alloy is made up of the primary η-Zn phase and eutectic structure at a high cooling rate. As the cooling rate decreases, the corrosion current firstly increased and then decreased due to decrease of the primary η-Zn content , the appearance and grew of α-Al phase. Moreover, the addition of Er leads to the formation of Er-containing intermetallic compounds in the Zn-5Al alloy, reducing the size of the primary η-Zn and α-Al phase, decreasing the corrosion current density, and improving the density and compactness of the corrosion product.

Effect of Erbium on Microstructure, Hardness and Electrochemical Properties of Al-5Zn-0.03In Alloy

Al-5Zn-0.03In series alloys have been widely studied and used as sacrificial anode materials. Adding rare-earth (RE) element to Al-5Zn-0.03In sacrificial anode is the important way to improve its microstructure and properties. This paper focused on the effect of Er addition on the microstructure and properties of the Al-5Zn-0.03In-xEr alloy. Thermal analysis showed that the presence of Er in the series alloys reduced the solidification ranges and made their liquidus and solidus move to lower temperature. The microstructural analysis and hardness testing reveal that Er existed in the form of precipitation, refined the dendrites of the series alloys and improved the hardness of the series alloys. Investigation of the potentiodynamic polarization and the electrochemical impedance measurements were performed in 3.5 wt. % NaCl solution. The potentiodynamic polarization results indicated that the corrosion potential increased and the corrosion current density reduced with the increase of the Er addition. The Al-5Zn-0.03In alloy shows higher corrosion resistance with the increase of Er content. The EIS electrochemical impedance results showed that Al-5Zn-0.03In anode presented relatively uniform dissolution due to the refined microstructure by the addition of Er.

Investigation on Microstructures and Mechanical Properties of the Hypoeutectic Al-10Si-0.8Fe-XEr Alloy

In this paper, the effect of Er addition (0.2, 0.5, 0.65, 0.8, 1.0, and 1.5 wt. %) on the microstructure evolution and tensile properties of as-cast hypereutectic Al-10Si-0.8Fe alloy was investigated. The phases and their morphologies in these alloys were identified by XRD and SEM equipped with EDX with the help of metallographic analysis techniques; the length of the secondary phase (LSP) and secondary dendrite arm spacing (SDAS) of α-Al grain were quantified. The results indicated that the second phases (primary Si, eutectic Si, and iron-rich phases) and α-Al grain were significantly refined when the addition of Er increased from 0 to 0.8 wt. %. The mean LSP and SADS values were decreased to a minimum value when the Er addition reached 0.8 wt. %. However, the second phases and α-Al grain became coarser when the level of Er increased more than 0.8 wt. %. The analysis of XRD shows that Er mainly exists in the form of Er2Si compound. The microstructure modification also has a significant effect on the mechanical properties of the alloy. The yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) increase from 52.86 MPa, 163.84 MPa, and 3.45% to 71.01 MPa, 163.84 MPa, and 5.65%, respectively. From the fracture surface, the promotions of mechanical properties are due to the dispersion and pinning reinforcement caused by the Er2Si phase.

Effect of Micro-Scale Er on the Microstructure and Fluidity of ZL205A Alloy.

The effect of Er addition on the fluidity and microstructure transformation of the as-cast and T5 heat-treated ZL205A alloys was investigated by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). The fluidity of the liquid metal after adding Er was tested and the fracture characteristics of the material were analyzed. The results indicated that Er was mainly dissolved into an α–Al matrix near the grain boundaries (GBs). It is easily segregated and enriched in the intersection of the GBs or the interface between the α and θ phase, which caused the intermetallic compounds to be distributed along the GBs to the neck and to fuse. Er could also inhibit the diffusion of Cu atoms in the process of solid solution, so that increased the residual eutectic structures in the crystal, while accelerating the precipitation progress of the Guinier–Preston (GP) zone and θ’ phase and increasing precipitation of the θ phase. A small amount of precipitation of θ phase and micro-scale Er (0.1–0.5 wt %) can significantly increase the fluidity and reduce the casting defects, which can effectively improve the castability of the ZL205A alloy. The interface between the (Al8Cu4Er) phase and matrix is the main area of microcracks, through analyzing the fracture morphology.

Effects of Er addition on the crystallization characteristic and microstructure of Al-2wt%Fe cast alloy

Effects of Er addition on the crystallization characteristic and microstructure of Al-2wt%Fe cast alloy have been investigated using cooling curve thermal analysis, optical microscopy, X-ray diffraction, SEM and TEM. Results showed that the Er addition has important effect on the crystallization characteristic of studied alloys. Thermal analysis indicated that at studied cooling rate of 1.3 °C/s, the Al-2wt%Fe cast alloy consists L→Al+Al3Fe eutectic transformation, while the alloy composes of L→Al+Al3Fe and L→Al+Al3Er eutectic transformation simultaneously with Er addition. The nucleation temperature of Al+Al3Fe eutectic increased first and then decreased with the increase of Er addition, the crystallization time of (Al+Al3Fe) eutectic decreased with the increase of Er addition. When Er addition is 0.3 wt%, the nucleation temperature has reached a peak of 650.95 °C. The addition of Er has a role of refinement on eutectic phase of Al-2wt%Fe alloy. As a favorable heterogeneous nucleation nucleus of eutectic α-Al, the primary Al3Er particle reduces the required undercooling and increases the nucleation rate. The average length of Al3Fe of 0.3 wt% Er reaches a minimum value of 37.69 μm, which is reduced by nearly half compared with that of Er free alloy. When Er content is 0.5 wt%, a small number of hollow square or diamond shaped Al3Er particles grown up to about 2 μm which can not be used as site of heterogeneous nucleation. With the content of Er from 0.1 wt% to 0.5 wt%, the growth temperature of (Al+Al3Er) eutectic increased from 626.46 °C to 635.41 °C. The supersaturated Er segregated at the α-Al/Al3Fe phase interface after solidification, and the orthorhombic Al10Fe2Er was found adhered to Al3Fe.

Temperature-insensitive strain and bright upconversion luminescence in Er-modified 0.88(Bi0.5Na0.5)TiO3-0.22(Bi0.5K0.5)TiO3 ceramics

In this work, 0.88(Bi0.5Na0.5)TiO3-0.22(Bi0.5K0.5)TiO3-xmol%Er (x = 0.00–0.80, 0.88BNT-0.22BKT-xmol%Er) lead-free piezoelectric ceramics were prepared by the solid state reaction method and the effects of Er addition on structure and electrical properties of 0.88BNT-0.22BKT ceramics were investigated. Results showed that Er additive within the content of 0.80mol% diffuse into the 0.88BNT-0.22BKT lattice to form a pure perovskite phase structure. Pure 0.88BNT-0.22BKT ceramic shows a large field strain of 0.21% at room temperature, but it is depended greatly on the temperature. As 0.4–0.8mol%Er doped into the 0.88BNT-0.22BKT host, they show a temperature-insensitive strain characteristic in the temperature range from room temperature to 120 °C. Furthermore, a large electrostrictive effect with high electrostrictive coefficient Q33 of 0.016–0.019m4/C2 comparable with that of traditional lead-based electrostrictors is obtained in these Er-modified materials. Moreover, Er-modified 0.88BNT-0.22BKT samples exhibit a strong green upconversion emission under a 980 nm LD excitation. These results suggest that this kind of material is promising candidate used as multifunctional devices by integrating its electrostrictive and upconversion luminescence properties.

The effects of Er addition on the microstructure and properties of an in situ nano ZrB2-reinforced A356.2 composite

In this study, the effects of Er addition on the microstructure and properties of in situ nano A356-3 wt%ZrB2 composites were investigated. The A356-3 wt%ZrB2 composite was prepared by an in situ reaction between K2ZrF6 and KBF4 salts, which were added in the proper stoichiometric ratio to form ZrB2 in the A356.2 alloy melt at 1123 K(850 °C). The addition of Er could modify the coarse lamellar eutectic Si particles into fine fibrous particles and refine the second dendrite arm spacing (SDAS) of the grains simultaneously. Furthermore, the Er also influenced the distribution and size of the ZrB2 particles by homogenizing the distribution of the nanoparticles and reducing their size. Tensile testing showed that the ultimate tensile strength (UTS), yield strength (YS) and elongation increased to 325 MPa, 250MPa and 13.65%, respectively, due to the homogeneous distribution of the nanoparticles, the refinement of the SDAS of the α-Al grains and the modification of the eutectic Si particles upon increasing the Er content to 0.05 wt% combined with T6 heat treatment.

Characterization of Innovative Al-Si-Mg-Based Alloys for High Temperature Applications

The role played by transition elements and rare earths, added in small quantities (fractions of unity in weight percent) was proved by several authors to be beneficial for the age-hardening response and for the microstructural stability at high temperature of Al-based alloys. The paper illustrates the results of an experimental investigation on the effects of erbium (Er) additions on the microstructural features, microstructural stability and mechanical properties of an Al-7Si-0.4Mg alloy of wide industrial use. The effects are multifold: in the cast microstructure, a silicon (Si) eutectic modification was observed with the formation of several Er-containing intermetallic phases. After solution treatment and aging, an increase in peak hardness and an enhanced microstructural stability were obtained. In this preliminary study, the beneficial effects of Er additions were confirmed.

Microstructure and mechanical properties of ZK60-Er magnesium alloys

The effects of Er addition on the microstructure and mechanical properties of ZK60 alloy were investigated. Cast ZK60-Er (0, 0.5, 1, 2 and 4wt%) ingots homogenized at 350°C were extruded at 400°C. It was found that Er primarily existed in the form of Mg–Zn–Er intermetallic particles instead of Er-containing α-Mg solid solution. Due to the formation of Mg–Zn–Er particles, the dissolution of Zn solutes in homogenized billets decreased with increasing Er modification. Typical fiber textures along with dynamically precipitated spherical Mg–Zn compounds were developed during the extrusion process. Mg–Zn precipitates gradually decreased with the increasing Er level. Er addition slightly decreased the elongation and scarcely increased the tensile strength of the extruded bars. The extruded alloys with different Er contents shared similar microstructural evolutions in the subsequent heat treatment. No Er-bearing precipitates were found in the heat treated bars. Mechanical strengths decreased but the plasticity increased by increasing the solutionization time from 1.5h to 12h at 400°C. Upon further aging at 200°C for 10h, there was no significant change in the optical microstructure while Mg–Zn compounds statically precipitated. The plasticity could be compensated by the decrease of defects caused by the static precipitation of Mg–Zn compounds.

Study of Aging Precipitation of Al-Zn-Mg Alloys with Er Additions by Monte Carlo Simulation

Our former experimental study showed that the addition of Er to Al-Zn-Mg alloys speeded up the aging precipitation, accelerated the precipitation of and enhanced the effect of aging strengthening distinctively. In this paper, the Monte Carlo method was applied to simulate the microstructural evolution of Al-2.6Zn-(2.3Mg)-(0.07Er), Al-2.6Zn-2.3Mg-(0.12Er), and Al-2.6Zn-2.3Mg-0.1(Er,Zr) alloys during aging. The effects of Er addition to Al-Zn-Mg alloys on the clustering of Zn and Mg atoms are studied through analysis of the simulation results and the effects on the subsequent aging process are discussed as well. The results show that the Zn/Mg/Er clusters appear beside the Zn clusters, Mg clusters and Zn/Mg clusters in the Er addition Al-Zn-Mg alloys. The Zn clusters and Zn/Mg clusters are finer in the Al-2.6Zn-2.3Mg-xEr alloys than that in the Al-2.6Zn-2.3Mg alloys without Er addition. The size of the Zn clusters and Zn/Mg clusters in the Al-2.6Zn-2.3Mg-0.07Er is eight percent and nineteen percent smaller than that in the Al-2.6Zn-2.3Mg alloys without Er addition respectively. This precipitation refinement effect of Er addition to the Al-2.6Zn-2.3Mg alloys is enhanced with the increment of Er content. These above results are consistent with the experimental results that the precipitation in the Al-Zn-Mg alloys with Er is finer and denser than that in the Al-Zn-Mg alloys without Er. The Er addition changes the clusters distribution in the Al-Zn-Mg alloys by its interaction with the main solute atoms and the vacancy, and thus influences the precipitations during subsequent aging processing.

Static recrystallization and grain growth during annealing of an extruded Mg–Zn–Zr–Er magnesium alloy

Microstructure stability is essential to maintain a fine grain structure for an alloy throughout its processing. The effects of Er addition and its existing form on the static recrystallization and grain growth during annealing of an extruded Mg–1.5Zn–0.6Zr magnesium alloy were studied in this paper. The results showed that microstructure stability was much improved by Er addition and the best thermability was obtained in 2 wt.% Er-containing alloy. For the incomplete dynamic recrystallization (DRX) microstructures extruded at a lower temperature of 350 °C, Er addition increased the resistance of static recrystallization; and for the complete DRX microstructures extruded at a relatively high temperature of 420 °C, Er addition suppressed grain growth. The difference in microstructure stability was then correlated with the microstructure features. Both the intermetallic phase and the solute atoms of Er in α-Mg matrix contributed to the microstructure stability. Moreover, it is believed that the existing form of Er–Zn atom pairs in the α-Mg solid solution favored the most to improve the thermal stability of the alloy.

Influence of Er addition and extrusion temperature on the microstructure and mechanical properties of a Mg–Zn–Zr magnesium alloy

Mg-1.5Zn-0.6Zr alloys with 0–4 wt.% Er addition were prepared by semi-continuous casting and extruded. The effects of Er addition and extrusion temperature on the microstructure evolution and mechanical properties were examined. The results showed that Er had a moderate grain refinement effect on the Mg-1.5Zn-0.6Zr alloy. The grain size was refined to ∼62 μm when adding 2 wt.% Er. Moreover, the addition of Er inhibited the formation of the divorced Mg–Zn binary eutectics and led to the formation of thermal stable Mg–Zn–Er intermetallics. The volume fraction of these intermetallic particles increased with increasing Er addition. Er was found to promote a higher degree of recrystallization and more homogenous microstructure when extruded at lower temperature of 350 °C. At higher extrusion temperature of 420 °C, Er effectively suppressed the grain growth; the Er-containing alloys demonstrated fine and uniform recrystallized grains of 4–6 μm in size. The comprehensive mechanical properties were greatly enhanced by the addition of Er. After extrusion at 420 °C, the 1 wt.% Er-containing alloy exhibited the best ultimate (305 MPa) and yield strength (285 MPa), with a large tensile elongation of 25%. The improved microstructure and mechanical properties could be ascribed to both the dissolved Er in the α-Mg solid solution and the thermal stable Mg–Zn–Er intermetallics.