Addition Of Er Research Articles

Effects of minor Nd and Er additions on the precipitation evolution and dynamic recrystallization behavior of Mg–6.0Zn–0.5Mn alloy

Abstract A new wrought magnesium (Mg) alloy based on Mg–6.0Zn–0.5Mn (ZM60) is developed, which performs excellent combination of high tensile yield strength and good ductility. We investigate the effects of micro-alloying on dynamic precipitation, dynamic recrystallization (DRX) and mechanical properties of ZM60 alloy. The co-addition of minor (0.6 wt%) neodymium (Nd) and (0.3 wt%) erbium (Er) can accelerate the twinning and DRX process of ZM60 alloy at the initial compression deformation stage. The dynamic precipitation process is also accelerated due to Nd and Er co-alloying. Dislocation accumulation disappears and a higher density of rod β 1 ′ precipitates and some thick β 2 ′ precipitates in matrix and fine twins, which inhibits the growth of DRX grains in compressed ZM60–0.6Nd–0.3Er alloy. The as-extruded ZM60–0.6Nd–0.3Er alloy has a yield strength (YS) of 245.8 MPa, ultimate tensile strength (UTS) of 347.2 MPa and elongation (EL) of 16.3%. The yield strength and tensile strength are improved via minor Nd and Er additions due to fine complete DRX grains, second phase particles and high density of precipitates. The grain refinement, weakened reserved working hardening and weakened basal fiber texture improve the elongation of ZM60–0.6Nd–0.3Er alloy.

Structural and electrical properties of Sm and Er co-doped ceria electrolytes

The aim of this study is to prepare Er and Sm co-doped CeO2 electrolytes via the Pechini method and investigate the effects of simultaneous addition of Sm and Er on the structural and electrical features of CeO2. The structural, functional group analysis, microstructures, and electrical properties of the electrolyte samples are conducted by X–ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and impedance spectroscopy (IS). All the calcined and sintered electrolytes were obtained with cubic fluorite crystal structure without secondary oxide phases. After sintering at 1400 °C, highly dense electrolytes were achieved (> 90%). The IS measurements indicated that the highest ionic conductivity was observed for the singly doped Ce0.80Sm0.20O1.90 (σ750 °C = 3.86 x 10−2 S/cm) electrolyte. σ750°C was found to be 3.82 x 10−2, 1.73 x 10−2, 0.61 x 10−2 S/cm for Ce0.80Er0.05Sm0.15O1.90, Ce0.80Er0.10Sm0.10O1.90 and Ce0.90Er0.10O1.95, respectively.

Tensile and creep properties of Al–7Si–0.3Mg alloy with Zr and Er addition

The combined and singular effects of Zr and Er addition on the microstructure, tensile and impression creep behaviour of the cast A356 alloy were investigated. The Zr and Er refined the α-Al dendrites and secondary dendrite arm spacing (SDAS) and modified the eutectic morphology. The simultaneous addition of Zr and Er exhibited the smallest α-Al dendrites and SDAS with a fibrous eutectic morphology, resulting in the highest yield (∼118 MPa) and tensile (∼190 MPa) strength, and the largest creep resistance. The stress exponent, and the activation energy, were within the range of 6.28–7.22 and between 121.6 and 148.2 kJ mol−1, respectively. The lattice self-diffusion climb-controlled creep was the dominant creep mechanism. The constitutive creep equation was developed for each alloy.

Synchronous improvement in room-temperature fracture toughness and high-temperature oxidation resistance of Nb[sbnd]Si based alloys with Erbium addition

The microstructure, room-temperature fracture toughness and high-temperature oxidation resistance of Nb-16Si-23Ti-4Cr-2Al-2Hf-xEr (x = 0, 0.1, 0.4, 0.6, at.%) alloys via directional solidification and heat treatment were investigated. Results showed that all the alloys consisted of Nbss, αNb5Si3 and γNb5Si3 phase, Er addition refined the microstructure, increased the volume fraction and continuity of Nbss matrix. Since the high-activity of Erbium, it is in-situ oxygenated to form a mixed oxide phase in the form of discreet particles, alloy melt got purification by internal oxidation mechanism. The higher density dislocations which may be induced by thermal expansion mismatch were piled up around the oxide particle compared with other regions in Nbss matrix. Er-doping contributed to eliminate segregation of Ti and then reduced its concentration-sensitive effect. Besides, more Nbss/silicide interface decohesion was triggered by addition of Er. So the 0.4 at.% Er addition significantly enhanced the fracture toughness of NbSi based alloys from 8.4 MPa·m1/2 to 24.5 MPa·m1/2 at room temperature. Er also accelerated the formation of complex oxide products and transition from linear oxidized regularity to parabolic, and obviously decreased the weight gain from 258.2 mg/cm2 to 164.3 mg/cm2 after oxidation at 1300 °C for 100 h.

Effect of trace Er on the microstructure and properties of Al–Zn–Mg–Cu–Zr alloys during heat treatments

The effects of trace Er on the microstructural evolution and mechanical properties of newly designed Al–Zn–Mg–Cu–Zr alloys for drilling pipes were investigated. After homogenization, most of the eutectics dissolved into the matrix and some primary phases remained, including Al8Cu4Er, Al12(Mn,Cr), and Al3Ti. Dispersed nano-sized Al3(Er,Zr) precipitates were formed in the Er-containing alloys after homogenization. Following extrusion, solution and retrogression re-aging (RRA) treatment, the hardness and yield strength of the 0.10 wt% Er-containing alloy are increased by 14% (25.4 HV) and 12.7% (70 MPa) compared to the alloy without Er. This improvement could be ascribed to the precipitation strengthening of fine Al3(Er,Zr) particles, which complemented the conventional η' phase precipitation strengthening. The intergranular corrosion resistance of the RRA-treated alloy with the addition of 0.10 wt% Er was improved by 65% due to a lower amount of high angle grain boundaries. The fracture and intergranular corrosion mechanisms in alloys with and without Er addition were linked to the respective grain structures.

Microstructure, mechanical properties and stretch formability of as-rolled Mg alloys with Zn and Er additions

The magnesium alloy has a unique advantage in 3C fields due to its high specific strength and excellent electromagnetic shielding characteristic. However, it is difficult to deform homogeneously because of hexagonal close-packed structure. In the present work, the microstructure, mechanical properties and stretch formability of magnesium alloy sheets with different alloying elements were investigated. It was indicated that a trace addition of Zn or/and Er made a key role in modifying texture, activating shear bands formation and precipitating nanoscale second phases, respectively, which resulted in an obvious improvement in both stretch formability and mechanical properties. The results suggested that the Mg–0.5Zn–0.5Er alloy sheet exhibited higher tensile strength along the rolling direction, i.e., yield strength of 180 MPa and ultimate tensile strength of 201 MPa, accompanying with superior Erichsen value of 7.0 mm at room temperature. The good performances of the sheet were ascribed to weakening basal texture intensity, formation of shear bands and precipitation of nanoscale W-phase (Mg3Zn3Er2). The microstructure, mechanical properties and stretch formability of magnesium alloy sheets with different alloying elements were investigated in the present investigation. It was indicated that a trace addition of Zn or/and Er made a key role in modifying texture (Fig. 1), activating shear bands formation and precipitating nanoscale secondary phases (Fig. 2), respectively, which resulted in an obvious improvement in both stretch formability and mechanical properties (Fig. 3).

Effects of Al8Cu4Er Phase on Corrosion Behavior of Al–Cu–Mg alloy with Er addition

The effect of Al8Cu4Er phase on the corrosion behavior of Al–Cu–Mg alloy with rare earth Er addition in an under-aging state was studied. The results revealed that the addition Er into the Al–Cu–Mg alloy induced the formation of Al8Cu4Er phase. The Al8Cu4Er phase can significantly refine the grains during recrystallization, thereby suppressing the continuous precipitation of S-phase at grain boundaries and improving the resistance to intergranular corrosion. Conversely, the corrosion susceptibility of local regions around the Al8Cu4Er phase with large dimension was higher than that of the AlCuFeMnSi phase, but weaker than that of θ phase, resulting in decreased pitting corrosion resistance.

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.

Outcome of mix Ce and Er addition on solidification microstructure of the LM25 ( Al-7Si-alloy)

Abstract This paper highlights the effects of the additions of two rare earth elements (Ce and Er) on microstructure and to investigate the characteristic temperatures during solidification to five modified alloy. Al-7Si alloys with xEr + xCe additions (x = 0.15, 0.25, 0.4, 0.5 and 0.75) were produced by casting technique via the solidification parameters examined using computer-aided cooling curve thermal analysis (CA-CCTA). The thermal analysis tests were carried out for each one by using a thermal analysis system that includes (K-type Thermocouple, EPAD2-TH8-K, EPAD-Baes and Laptop with Dewesoft-7.5-Lt). To estimate the change in microstructure and solidification as a result of adding (Ce + Er) additions the obtained result showed that the growth TGAl-Phase and nucleation TNAl-Phase temperatures decreased to lower temperatures 614.7 °C and 615.5 °C respectively as the amount Ce, Er increased. A high amount of Ce, Er (1.5%) addition reduces the size of the platelet Si-intermetallic to very fine form.

Structural characterization, optical and PAL spectroscopy studies of Er3+-doped Ge20Ga5Sb10S65 glasses

The Ge20Ga5Sb10S65 glasses doped with Er3+ ions (0; 0.1; 0.5; 1.0 mol. %) are investigated with optical, fluorescence and positron annihilation lifetime (PAL) spectroscopies. The optical and fluorescence measurements were performed at room (TR) and liquid nitrogen (TLN) temperatures. Transitions of Er3+ ions from the 4I15/2 ground energy level to their higher levels 4F9/2, 4I9/2, 4I11/2 and 4I13/2 are well observed at both temperatures as absorption peaks at ~660, 810, 985 and 1540 nm, respectively. At TLN temperature, it is also possible to resolve the absorption band at ~550 nm, which corresponds to 4I15/2→4S3/2 transition. The most intense fluorescence emission is observed at ~1 μm and ~1.5 μm wavelengths, which are identified as 4I11/2→4I15/2 and 4I13/2→4I15/2 radiative transitions of Er3+ ions. It is shown by PAL spectroscopy, that the addition of Er causes an increase of positron lifetime in defects τ2 and a decrease in the intensity I2 of the corresponded lifetime component. These changes are explained in terms of positron trapping reduction due to the occupation of positron trapping Ga-based sites in the glass matrix by Er3+ ions.

Effects of strontium - erbium co-doping on the structural properties of hydroxyapatite: An Experimental and theoretical study

Five different samples of Sr-based Er-doped hydroxyapatites (HAps) in the dissimilar quantities like 0, 0.35, 0.70, 1.05 and 1.40 at% were produced via a wet chemical process. The prepared samples were investigated experimentally by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared (FTIR) spectroscopy, differential thermal analysis (DTA), and in vitro biocompatibility tests. In addition, the density of states (DOS) and band structures were investigated theoretically. It was found that the presence of Er as a dopant affected the lattice parameters, while the EDX measurements confirmed that the presence of Er at various concentrations caused a Ca-deficiency because the addition of Er decreased the Calcium/Phosphorus molar ratio from 1.67 to 1.61. For all samples, the single-phase distribution of HAp was observed. The crystallinity percentage of the samples was found to be 89% or more according to two different methods. The calculations with respect to Scherrer and Williamson-Hall methods showed that the crystallite sizes of the samples were found to be in the ranges of 29–34 nm and 25-42 nm, respectively. DTA investigations revealed that all samples exhibited thermal stability in the temperature range of 25 °C - 1000 °C. No remarkable morphological alterations were observed. Furthermore, the theoretical studies confirmed that the band structures narrowed with an increase in Er concentration.

Effect of combined Ce and Er Addition on Solidification, Microstructure of the Al-7Si-alloy

This paper highlights the effects of the additions of two rare earth elements (REEs) (Ce and Er) on microstructure and to investigate the characteristic temperatures during solidification of the modified alloy. Five changes of Al-7Si alloys with xEr+xCe additions (x=0.15, 0.25,0.4, 0.5 and 0.75) were produced by casting technique via the solidification parameters examined using computer-aided cooling curve thermal analysis (CA-CCTA). The thermal analysis tests were carried out for each one by using a thermal analysis system that includes (K-type Thermocouple, EPAD-TH8-K, EPAD-Baes2 and Laptop with Dewesoft-7.5-Lt). To estimate the change in microstructure and solidification as a result of adding (Ce+Er) additions, the obtained result showed that the growth TG Al-Phaseand nucleation TNAl-Phasetemperatures decreased to lower temperatures 614.7°C and 615.5°C respectively as the amount Ce, Er increased.

Mechanical properties and crystallization kinetics of Er-containing Cu–Zr–Al bulk metallic glasses with excellent glass forming ability

Investigations were carried out to explore the consequences of Er adding on the glass forming ability (GFA), mechanical properties, and crystallization kinetics of Cu50Zr43Al7 bulk metallic glass (BMG). It is found that the (Cu50Zr43Al7)100-xErx (x = 0, 2, 4, 6 at %) BMGs reflects its best GFA at x = 2 and correlate well with GFA indicator (γ and K) and thermal stability parameter (ΔTx). The Er-containing BMGs showed high compressive strength and Young module in the range of 1816–1890 Mpa and 116–120 GPa, respectively, but no plastic deformation observed in them. The crystallization kinetics lagged with 2 at % Er addition. The large atomic radius of Er and large negative mixing enthalpy of Er with the other constituent elements causes the significant atomic size mismatch and the formation of short-range order in the melt which restrict the long-range diffusion and ordering of atoms that lead to improving GFA and lagging the crystallization kinetics of (Cu50Zr43Al7)98Er2.

Effect of Er on Microstructure and Mechanical Properties of 5052 Aluminum Alloy with Big Width-To-Thickness Ratio.

The effect of Er on microstructure and mechanical properties of the 5052 aluminum alloy with a big width-to-thickness ratio was investigated by a metallurgical microscope, scanning electron microscope and tensile testing machine. The results showed that the precipitates were slightly refined after Er addition and Al3Fe was transformed into Al6Fe and AlEr with/without a small amount of Fe or Si. The effect of Er on grain refinement was related to its content. When Er content was lower or higher than 0.4%, the grain would coarsen. Homogenization could refine the grain by controlling Er content and distribution in the Al matrix. Long time homogenization at high temperature would significantly reduce the strength of the 5052 aluminum alloy and 5052 aluminum alloys with low Er content, but help to improve the plasticity of those with high Er content. The ultimate tensile strength, yield strength and elongation of the as-cast 5052 aluminum alloy were 197 MPa, 117 MPa and 22.5% respectively. The strength was the highest, when Er content was 0.4 wt. % and the elongation was the best at 0.1 wt. % Er content.

Microstructural changes induced by Er and Zr additions to A356 alloy investigated by thermal analyses and STEM observations

This work is aimed at characterizing the changes induced in the microstructure of an Al-7Si-0.4Mg (A356) alloy when 0.3 wt% Er (alloy E3) and 0.3 wt% Er plus approximately 0.5 wt% Zr (alloy EZ35) are added. The addition of Er and Zr caused the precipitation of Al3Er and Al3(Er, Zr) precipitates during solution heat treatment, as it was shown by isothermal DSC tests performed at the solution treatment temperature, microhardness measurements on samples subjected to different solution treatment time and STEM micrographs. The age hardening response of Er- and Zr-containing A356 is improved, thanks to the formation of further Al3Er and Al3(Er, Zr) precipitates during aging. Er- and Zr-containing precipitates were also identified inside eutectic Si and were identified as Al2Si2Er and Al2Si2(Er, Zr) for E3 and EZ35, respectively. Finally, an Er-rich layer was identified at the interface between eutectic Si and Al after thermal treatment, possibly formed by Er atoms diffusing along the Si twins and accumulating at the eutectic Si interface with the Al matrix.

Effect of Rare Earth Er on Microstructure and Creep Behavior of Al–7Si–0.3Mg Alloy

The effect of 0.25 wt% and 0.5 wt% rare earth Er addition on the microstructure and creep behavior of the cast A356 alloy was investigated. The microstructure of the alloys before and after the creep was evaluated by optical and scanning electron microscopy equipped with energy dispersive spectrometry. The creep behavior was examined by the impression creep test at the temperature range of 493 to 553 K under the stresses between 480 and 680 MPa. Results showed that the addition of Er addition caused the α-Al dendrites to refine and the morphology of the eutectic silicon to modify significantly. The microstructure of the A356 alloy with Er addition was characterized by Er-rich intermetallics. The lattice self-diffusion climb-controlled creep was found to be the dominant creep mechanism in all alloys. The addition of Er improved the creep resistance of the A356 alloy and the alloy modified with 0.5 wt% Er exhibited the highest creep resistance.

Effects of Er and Zr Additions on the As-Cast Microstructure and on the Solution-Heat-Treatment Response of Innovative Al-Si-Mg-Based Alloys

The microstructure of Al-Si-Mg alloys strongly depends on their chemical composition and the heat treatment they undergo during production. The influence of solution heat treatment (SHT) and the addition of Er and Zr on the microstructure of gravity-cast A356 (Al-7Si-0.4Mg) were examined. The reference as-cast microstructure is characterized by the grain size and morphology of eutectic Si, as well as the morphology, area fraction, and chemical composition of the intermetallic compounds. The morphology of eutectic Si is unstable during SHT; the evolution mechanisms can be described using thermodynamic and kinetic models and have been validated using optical and scanning electron microscope (SEM) micrographs. The effect of high-temperature exposure during SHT, on the other hand, plays a minor role on the quantity and morphology of the intermetallic compounds, as demonstrated by optical and SEM micrographs.

Constitutive Behavior of an AA4032 Piston Alloy with Cu and Er Additions upon High-Temperature Compressive Deformation

Aluminum piston alloys of the AA4032 type are produced by direct-chill (DC) casting and subsequent forging; therefore, it is important to understand their thermomechanical behavior. In recent years, it was shown that additions of Cu and Er could improve mechanical properties of these alloys at room and high temperatures. In this work, we studied the constitutive behavior of AA4032-type alloys with and without Cu and Er additions. The experimental true stress–true strain curves were obtained by compression tests under various temperatures [683 K to 723 K (410 °C to 450 °C)] and strain rates (0.01 to 10 s−1) to determine constitutive parameters [strain-rate sensitivity, activation energy, and Zener–Hollomon (Z) parameter] for the hot deformation behavior of AA4032-type piston alloys with and without additions of Cu and Er. The flow stress decreased with increasing deformation temperature and decreasing strain rate. The results also showed that increasing the Cu content increased the flow stress over the applied range of deformation conditions due to solid-solution strengthening and the formation of primary Si particles, which led to an increase in the activation energy during hot deformation. Moreover, the main microstructural damage in the AA4032 alloy with 3.5 pct Cu was predominantly due to the cracking of primary Si particles. Additions of 0.4 pct Er and 3.5 pct Cu lower the activation energy of deformation, Q, as compared to the base alloy and the alloy with 3.5 pct Cu. The microstructures in the deformed specimens consisted of subgrains, recrystallized grains, and fine eutectic phases. The alloys containing Er demonstrated more polygonized grains at a low strain rate than the alloys without Er, indicating that Er hindered recrystallization development. The peak stress of the AA4032 alloy with 3.5 pct Cu alloy was higher than for the base AA4032 alloy and for the AA4032 alloy with 3.5 pct Cu and 0.4 pct Er additions, which was attributed to the prevalence of the work-hardening mechanism over the softening mechanism.

Synergistic reinforcement of in situ (ZrB2+TiB2) particles and Er on microstructure and properties of 6082Al matrix composites

In present work, the effects of in situ (ZrB2+TiB2) particles and rare earth element Er on microstructure and mechanical properties of 6082Al matrix composites were investigated respectively. On the basis of research above, the characteristics of synergistic enhancement of them can be analyzed. The results indicated that the mechanical properties of 6082Al-3wt%(TiB2+ZrB2)-0.5 wt%Er composites reached to the maximum values with YS, UTS and elongation were 285 MPa, 330 MPa and 11.7% respectively, which increased by 13.1%, 13.8% and 85.8% respectively compared with the 6082Al matrix alloy. The addition of Er to the 6082Al-(TiB2+ZrB2) composites contributed to the notable modification on distribution and morphology of in situ particles that the large particle clusters almost disappeared and the size of TiB2 and ZrB2 particles decreased a lot compared with the situation without Er addition. The grain size of the matrix alloy decreased from 115.4 μm to 43.8 μm when the Er addition is 0.5 wt%. The Er-containing precipitates and in situ TiB2 and ZrB2 particles were confirmed by Optical microscope, Scanning electron microscopy, Transmission electron microscopy, Energy dispersive spectroscopy, and X-ray diffraction.

On the role of Sc or Er micro-alloying in the microstructure evolution of Al-Mg alloy sheets during annealing

Microstructure evolutions of a Sc-containing and an Er-containing Al-Mg alloy during annealing process were investigated comparatively. Microhardness of the Er-containing alloy decreases with the increase of annealing temperature and a dramatic decrease is observed between 300 °C and 400 °C. Electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) results show that the recrystallization process of the Er-containing alloy finishes rapidly between 350 °C and 400 °C, resulting in the formation of large recrystallized grains and the loss of sub-structure strengthening. In comparison, the Sc-containing alloy shows good thermal stability and the dramatic decrease of microhardness occurs between 450 °C and 550 °C. The Sc-containing alloy maintains sub-structures even after annealing at 400 °C for 1 h. The different recrystallization behavior of the two alloys is attributed to the fact that Al3(Scx, Zr1-x) dispersoids have higher thermodynamic stability than Al3(Erx, Zr1-x) dispersoids. Cold-rolled sheets of the two experimental alloys exhibit typical rolling texture, mainly consisting of Brass, Copper, and S orientations. Texture components of the two alloys dramatically change to random orientations once recrystallization completes. In-situ high-temperature XRD results reveal that dislocation density of the Sc-containing and the Er-containing cold-rolled sheets decreases rapidly with the increase of temperature. Sc or Er addition does not exert significant influence on the annihilation of dislocation at low-temperature annealing (below 250 °C).