Zr Phase Research Articles

Effects of Si addition on properties and microstructure of CuCrZr alloy

In order to develop high-strength and high-conductivity copper alloys with better comprehensive properties, the effects of Si addition on the mechanical properties, electrical conductivity and microstructure of CuCrZr alloy were investigated in this paper. The addition of Si element can improve the hardness, strength and ductility of CuCrZr alloy. The optimal peak aging parameter for CuCrZrSi alloy is 430 °C for 3 h, the hardness 228.92 HV, the tensile strength 646.76 MPa, and the elongation after fracture 10.67%. Compared with the CuCrZr alloy under the same process, the mechanical properties are increased by 10.3%, 11.9% and 16.9%, respectively. The conductivity is 4 ± 1%IACS lower than that of the sample without Si addition. The addition of Si element refines the deformation substructure and produces more Σ3n (n = 1, 2, 3) grain boundaries, thus providing more nucleation sites and higher driving forces for the precipitation phases. In both CuCrZr and CuCrZrSi alloys, the fine precipitation phases (<10 nm) fcc-Cr phase and orthorhombic-Cu8Zr3 phase, together with coarse precipitation phases (>100 nm) bcc-Cr phase and hcp-Zr phase can be observed. The orientation relationship among the two fine precipitation phases and the matrix is (1¯1¯1)[11¯0]Cu∥(1¯1¯1)[11¯0]Cr∥(133)[01¯1]Cu8Zr3. The Si element tends to precipitate together with the Cr phase and Zr phase, and acts to refine and spheroidize the precipitation phases.

Flash joining of 3YSZ and 430 SS using Ag–CuO filler

Conventional reactive air brazing (RAB) of stainless steel (SS) to ceramic components usually encounters Cr oxidation and joint embrittlement problems due to high temperature and long dwelling time. Herein, 3 mol% yttria-stabilized zirconia (3YSZ) and 430 SS were joined using an Ag–CuO filler in seconds at relatively low temperatures (875 °C–1050 °C) with the assistance of a direct current passing through the seam. The applied current promoted the melting of the filler and rapid filling of the gap due to Joule heating effect. Also, it facilitated atomic/ionic transport and interfacial reaction. Key joining parameters including current density, joining time and furnace temperature were investigated, and a maximum joint strength of 158 ± 9 MPa was achieved at a current density of 4 A/cm 2 for 30 s at 950 °C, which is approximately 50% higher than that of the RAB joints. The formation of AgCu 4 Zr and Zr-rich intermetallic phases at the 3YSZ/Ag and Ag/430 SS interfaces, respectively, together with the suppression of the growth of Cr-containing oxide, was responsible for the robust joining.

DIFUSIÓN DE HIDRÓGENO EN HCP Zr

We study the behavior of hydrogen (H) in theαandβphases of Zr and in theβphase of Nb, using the Siesta andVasp first principles codes based on the density functional theory (DFT). We calculate the hydrogen solution energy, the binding energy of the H-H and H-Nb complexes, as well as, the mixing energy of the Zr-Nb system. Furthermore, we have proposed a simple model for the study of the hydrogen diffusion (DH) mediated by interstitial mechanism in hcp Zr. We find that interstitial hydrogen diffuses isotropically according to DH=1.1×10−7exp(−42 KJ.mol−1/RT)(m2/s). Our results are in good agreement with experimental data and other Kinetic Monte Carlo (KMC) calculations. Finally, the formation energies of the three most stable hydrides in the hcp Zr phase were also calculated.

Beneficial effects of Sc/Zr addition on hypereutectic Al–Ce alloys: Modification of primary phases and precipitation hardening

Al–Ce alloys possess desirable elevated-temperature performance due to the high stability of Al11Ce3 phases. The morphology and size of the Al11Ce3 phases play a significant role in determining the strengthening effect in Al–Ce alloys. In this paper, the effect of Sc/Zr addition on the microstructure, mechanical properties, and thermal stability of a hypereutectic cast Al–Ce alloy was investigated. The results demonstrated that Sc and Zr atoms could adsorb on the Al11Ce3 phase surfaces and control the growth process in the 0.13 wt % Sc-0.06 wt % Zr addition alloy, along with the size of primary Al11Ce3 phases was refined from ∼79 μm to ∼56 μm. As the total Sc/Zr content increased, the formation of primary Al3(Sc, Zr) phases could significantly refine the primary Al11Ce3 phases by acting as heterogeneous nucleation sites. Therefore, in 0.23 wt % Sc-0.16 wt % Zr and 0.49 wt % Sc-0.23 wt % Zr alloys, the modification effect on primary Al11Ce3 phases was based upon the interaction of adsorption effect and heterogeneous nucleation. The sizes of primary Al11Ce3 phases were refined to ∼37 μm and ∼32 μm, leading to a significant improvement in ultimate tensile strength (from ∼117 MPa to ∼182 MPa), yield strength (from ∼75 MPa to ∼145 MPa) and elongation (from ∼1.4% to ∼3.4%) in the 0.49 wt % Sc-0.23 wt % Zr alloy compared to the unmodified alloy. The Sc and Zr atoms that were dissolved in the matrix as a decomposed solid solution precipitated the L12-Al3(Sc, Zr) phases after thermal exposure, which maintained full coherency with the Al matrix, leading to a hardness increase, rather than a decrease, after 300 °C and 400 °C thermal exposure. Therefore, Al–15Ce-(Sc–Zr) alloys open a new alloy system for engineering materials useable in high-temperature applications.

Revisiting alloy design of low-modulus biomedical β-Ti alloys using an artificial neural network

An ensemble neural networks model is developed to detangle the complex effects of alloying elements on phase stability and Young's modulus, enabling design guidelines for low-modulus Ti alloy. This computational framework, which is named βLow 2.0, is validated and examined to understand the sensitivity of the modulus to the alloy composition for material selections. The exercise provides design guidelines for future material designs considering metastability of β phase and effects of Nb, Zr, Mo, Sn, and Ta. To evaluate this data-driven model, a basic uncertainty quantification function is applied to understand the model in the present data space. The results of the model validation are also presented with experimental data different from that of the calibration dataset. This work enables comprehensive metallurgical principles for alloy design by using neural network-based machine learning.

Effects of retrogression and re-aging treatment on precipitation behavior, mechanical and corrosion properties of a Zr+Er modified Al-Zn-Mg-Cu alloy

The microstructure, mechanical properties, and corrosion resistance of a Zr + Er modified Al-Zn-Mg-Cu alloy after different retrogression and re-aging (RRA) treatments were investigated. Results show that the main precipitates after different heat treatment change from GP zones + η’ + Al 3 (Er, Zr) phase (T6) to η’ + Al 3 (Er, Zr) phase (RRA180–30) and then to η + T phase (RRA200–30). The component, size, and distribution of precipitated phases would be affected by the regression time and temperature during RRA treatment. It is concluded that the uniformly dispersed precipitate phase in matrix and narrow precipitate-free zones (PFZs) could significantly improve the strength of Al-Zn-Mg-Cu alloy, and the grain boundary precipitated phase (GBPs) with moderate size and large interparticle distance could improve the alloy's corrosion resistance. Besides, a wider PFZ within a certain range is beneficial to improve the intergranular corrosion (IGC) performance. Therefore, it is important to accurately control the heating temperature and retrogression time during the retrogression stage to regulate the characteristics of precipitated phases and achieve the best balance of mechanical properties and corrosion resistance. • The precipitates size of RRA sample was larger and discontinuously distributed in GB. • Uniform precipitates in matrix and narrow PFZ are beneficial to the alloys' strength. • Corrosion resistance was improved with increasing retrogression temperature and time. • The wide PFZ and discontinuous GBP could improve the IGC resistance of the alloy.

Structure and stability of δ-UZr2 phase in U-50 wt% Zr alloy

ABSTRACT Thermodynamic stability of the hexagonal delta phase has been discussed for the U-50 wt% Zr alloy composition based on the XRD, FESEM, and EDS results, further corroborated by the ab-initio calculations. It has been shown that U-50 wt% Zr composition falls into a two-phase region in the U–Zr phase diagram at about 573 K, in contradiction to the published phase diagram. Crystallographic structure of the delta phase in terms of the atomic occupation has been elucidated using the near-neighbour analysis obtained from the EXAFS results. It is shown here that the (111) plane collapse mechanism of the parent bcc phase is not complete in the delta phase even after the sample was aged for 864 ks (240 h) at 573 K.

Microstructure, tensile properties and heat-resistant properties of selective laser melted AlMgScZr alloy under long-term aging treatment

Selective laser melting (SLM)-processed AlMgScZr alloy has aroused widespread interest in the aerospace industry due to its outstanding comprehensive performance and excellent heat resistant properties. The fine grain morphology and diffusely distributed thermally stable precipitates of this alloy are believed to play a critical role in its high-temperature performance. By modifying the alloy with Sc and Zr, nano-sized Al3(Sc, Zr) phases can act as heterogeneous nucleating particles to effectively promote grain refining and precipitate strengthening. In this paper, a Sc and Zr-modified Al–Mg alloy was printed by SLM, and the long-term aging treatments in the temperature range of 275–350 °C with a constant holding time of 144 h were performed to investigate the heat-resistant properties of this alloy. Under as-fabricated condition, the AlMgScZr alloy exhibited high tensile strengths of 487.7 MPa and 393.9 MPa at temperatures of 25 °C and 200 °C, respectively. When the alloy was aged at 300 °C for 144 h, its grain morphology was almost unchanged, but its tensile strength and elongation at room temperature reached 501.3 MPa and 31.3%, respectively.

A study on Sc- and Zr-modified Al–Mg alloys processed by selective laser melting

In this study, Al-4.6Mg-0.66Sc-0.42Zr-0.49Mn (wt.%) alloy was processed by selective laser melting (SLM). The relative densities of SLM-processed Al–Mg-Sc-Zr-Mn alloy reached up to 99.92%. The optimal energy density range is 60–80 J/mm3. The optimal laser power, scanning speed and hatch distance is 200–250 W, 800–900 mm/s and 135–165 μm, respectively. The two factors that have the greatest effects on relative densities are laser power, and the interaction between laser power and scanning speed. The effect of hatch distance on relative densities is comparatively small. During the SLM process, fine equiaxed grains were formed inside the melt pool and coarse columnar grains were formed at the melt pool boundary. A large number of nano-scale Al3(Sc, Zr) phases were precipitated and uniformly dispersed in the matrix, which effectively improved the mechanical properties and high temperature stability of the material. The samples were aged at an isothermal temperature of 350 °C for 8 h. After aging treatment, some of the low-angle grain boundaries were transformed into high-angle grain boundaries, which improved the hindering effect on dislocations. The mechanical properties of the heat-treated samples were excellent, with the maximum tensile strength and elongation reaching 510 MPa and 11%, respectively. The samples were mainly fractured by a mixture of brittle and ductile cracking mechanism, with brittle fracture in the columnar grain region and ductile fracture in the equiaxed grain region. The equiaxed grains have better effects on the mechanical properties of the alloy than the columnar grains.

Nucleation mechanisms in a SiO2-Li2O-P2O5-ZrO2 biomedical glass-ceramic: Insights on crystallisation, residual glasses and Zr4+ structural environment

In manufacturing reliable glass-ceramics, bulk chemistry and appropriate thermal treatments are critical points. To better understand the influence of nucleation parameters on the crystallisation behaviour and mechanical properties of multicomponent glass-ceramics, we studied the effects of time and temperature on phase stabilisation, the evolution of the crystal phases and physical properties of a Zr-rich lithium-silicate having a SiO2/Li2O molar ratio < 2. Here, we also provide insights into the structural environment of Zr4+ at the early stage of nucleation by Anomalous X-ray Scattering (AXS). By reverse-engineering a commercial material through remelting and sequential thermal treatments, we observed the strong effect of the nucleation temperature on the final mineral assemblage and of the volume fractions of the lithium-disilicate phase on the fracture toughness (KIc). Indeed, the KIc value was increased from ∼0.8 MPa.m½ in the pristine glass up to ∼ 2 MPa.m½, if compared to the original commercial material exhibiting a KIc value of 1.6 MPa.m½. Furthermore, the synthesis of residual glasses at different stages of the thermal treatments allowed us to observe the changes in the glass network structure and properties. AXS was used to extract the contribution exclusively coming from Zr for different nucleation steps. The differential pair distribution functions ΔZrg(r) show two distinct peaks at ∼2.10 Å and 3.44 Å, respectively associated with Zr-O and Zr-Zr/Zr-Si correlations with the formation of edge sharing in addition to corner sharing polyhedra. It was discerned the occurrence of (sub)nano-sized clusters enriched in Zr. These local clusters do not show changes during the different thermal treatments, either for higher temperatures or longer times. No Zr phases are stabilised in the crystallised materials, suggesting that these clusters do not evolve above the critical nucleus size. All evidence points to a highly heterogeneous environment and the coexistence of three structural regions i) (sub)nano Zr-clusters, ii) P enriched μ-areas, iii) residual silicate glass. The evolution and spatial distribution of these units influence the final properties.

Emulation of neutron damage with proton irradiation and its effects on microstructure and microchemistry of Zircaloy-4

This work assesses the potential of proton irradiation to simulate the neutron damage to the matrix and laves phase Zr(Fe,Cr)2 precipitates in Zircaloy-4. Isothermal proton irradiation has been performed on Zircaloy-4 samples at irradiation temperatures ranging from 250 to 350 °C. Two-step proton irradiation was also performed to enhance the amorphization of and iron loss from the laves phase Zr(Fe,Cr)2 precipitates. The irradiated microstructures, including dislocation loops and rafts near SPPs, were observed in proton irradiated Zircaloy-4, which are consistent with neutron irradiated material at a similar damage level. The amount of irradiation-induced hardening after proton irradiation was similar to post neutron irradiated data. The significant amorphization of the SPPs and concurrent Fe redistribution observed on neutron irradiated materials can be effectively emulated using a two-step proton irradiation on Zircaloy-4. Hence, the neutron irradiation effect on Zircaloy-4 can be mostly captured using the two-step proton irradiation described in this study.

Revealing the role of Al in the microstructural evolution and creep properties of Mg-2.85Nd-0.92Gd-0.41Zr-0.29Zn alloy

The influence of Al (0.5 wt%, 1 wt%, 2 wt%) on the microstructural evolution and creep resistance of Mg-2.85Nd-0.92Gd-0.41Zr-0.29Zn (El21) alloy was systematically investigated. The creep results revealed that the additions of 0.5 wt% and 1 wt% Al significantly decreased the creep rate of El21 by more than an order of magnitude, whereas 2 wt% Al in El21 led to the reduction of creep properties. Microstructural analyses indicated that the additions of 0.5 wt% and 1 wt% Al led to significant grain coarsening due to the consumption of Zr via the formation of Al2Zr3 and Al2Zr phases. In contrast, the addition of 2 wt% Al caused distinct grain refinement, resulting from the additional formation of lumpy Al2RE in the centre of α-Mg grains. Additionally, the increase of Al content in the El21 gradually led to the disappearance of the Mg3RE phase and left Al2RE as the only dominant phase. The main Al–Zr phase was also changed from Al2Zr3+Al2Zr to Al2Zr phase. Creep data analysis showed that the dominant creep mechanism was dislocation creep for all alloys, which was in agreement with the EBSD and TEM characterizations. The enhanced creep resistance via the addition of 0.5 wt% and 1 wt% Al was ascribed to the high area fraction of intermetallic phases and the additional formation of the thermally stable Al2RE phase. El21 + 0.5Al has better creep resistance than El21+1Al, which was attributed to its stronger dynamic precipitation strengthening from γ precipitates. The deteriorated creep properties caused by adding 2 wt% Al in El21 alloy arose from the bimodal inhomogeneous distribution of grains and the laminar Al2RE phase. Such microstructure might cause significant stress concentrations and could not effectively impede dislocation motion or reinforce the grain/dendritic boundaries during creep, thus deteriorating the creep properties of El21+2Al.

The effect of Er and Zr ratio on microstructure evolution and mechanical properties of 6061 aluminum alloy

In the present study, the 6061 alloy was chosen as base alloy, and micro-alloying effect of different ratios of Er and Zr (2:1, 1:1) on microstructure evolution and mechanical properties was examined after T6 heat treatment. Hot rolling deformation was carried out at 450°C, then a solution aging heat treatment process was adopted at 570°C/0.5h+180°C/5h. The precipitation, recrystallization behaviors were characterized using transmission electron microscopy(TEM), scanning electron microscope(SEM) and electron backscattered diffraction(EBSD) techniques, the mechanical properties were tested using tensile tests. The results shown that recrystallization behavior was inhibited by co-additions of Er and Zr. With the increase of Er and Zr content, the recrystallized grain size and coarse Fe-rich phases at the grain boundaries decreased, the recrystallized grain distributed uniformly, the number of needle-like Mg2Si and granular Al3(Er, Zr) phases gradually increased. In 6061 alloy with Er/Zr ratio of 1, the distribution of precipitates were finer and more uniform, The uniformly distributed Al3(Er, Zr) phases pinned the grain boundaries, which effectively hindered the movement of grain boundaries. The tensile tests exhibited that the properties of 6061 alloy with Er/Zr ratio of 1 reached the highest level, i.e., tensile strength of 344.0MPa, the yield strength of 296.0MPa, and elongation of 17%.

Understanding wear mechanisms of TiSiCN/Zr(C)N coatings at elevated temperatures

TiSiCN/ZrN coating and TiSiCN/ZrCN coating were prepared using multi-arc ion plating technology. In this work, the composition, mechanical properties and wear properties at elevated temperatures of both coatings were investigated. XRD results show that both coatings are composed of Ti, Zr (C, N) phases. At elevated temperatures, TiSiCN/ZrCN coating exhibits a lower friction coefficient and slightly higher wear rate compared to TiSiCN/ZrN coating. The result is that the introduction of C plays the role of lubrication and friction reduction effect, but the more content carbon leads to increased brittleness of the coating, and cracks are prone to occur and propagate under the effect of thermal and mechanical coupling, thereby causing the wear rate of the coating increased. The increased brittleness of TiSiCN/ZrCN coating is confirmed via mechanical properties. Under high temperature wear, a thin oxide layer formed on both coatings surface acts as a glaze to impede wear and it would break down to form a transfer layer under period force. At 500 °C, TiSiCN/ZrN coating and TiSiCN/ZrCN coating display the mechanisms of adhesive wear and abrasive wear, respectively.

Microstructure and mechanical properties of Al-Fe-Sc-Zr alloy additively manufactured by selective laser melting

An Al-5Fe-1Mg-0.8Sc-0.7Zr (wt%) alloy was specifically designed for selective laser melting (SLM) additive manufacturing and atomized powder prepared. The design of this non-equilibrium alloy is based on: first, solid solubility of Fe element in Al alloy can be significantly enlarged during laser rapid solidification; second, Sc and Zr elements are used to refine the microstructure so as to prevent micro-crack and improve strength. At an optimized printing parameters, the SLM printed Al-Fe-Sc-Zr samples exhibited a highest density of 99.2% with rare intergranular cracks. Besides, a bimodal grain structure was observed, consisting of ultrafine equiaxed grain at molten pool boundary and coarse columnar grain inside the molten pool. At the boundary of molten pool, many intermetallic particles (Al 6 Fe and Al 13 Fe 4 ) appeared around supersaturated α-Al grains; while the inside of molten pool presented eutectic of α-Al and Al 6 Fe/Al 3 (Sc, Zr). Interestingly, a large number of stacking faults were observed around the precipitated particles by HRTEM, which are also conducive to strengthening of SLM printed Al-Fe-Sc-Zr sample. Thus, excellent tensile strength of 489 MPa was obtained at an optimized volumetric energy density (VED) of 70 J/mm 3 . The current research results have a certain guiding significance for the composition design and microstructure control of additive manufacturing aluminum alloys. • High Fe-content Al-Fe-Sc-Zr alloy was successfully printed by selective laser melting. • The microstructure is composed of supersaturated solid solution and fine precipitates. • An eutectic microstructure of α-Al and Al 6 Fe/Al3(Sc, Zr) phases was found. • YS and UTS of SLMed alloy reached 388 ± 14 MPa and 489 ± 6 MPa, respectively.

Microstructure and Nanoindentation Behavior of Ti40Zr40Ni20 Quasicrystal Alloy by Casting and Rapid Solidification

A Ti40Zr40Ni20 quasicrystal (QCs) rod and ribbons were prepared by conventional casting and rapid solidification. The X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC) techniques were used to investigate the microtissue, phase composition, and solidification features of the samples; the nano-indentation test was carried out at room temperature. The results show that a mixture of the α-Ti(Zr) phase and the icosahedral quasicrystal (I-phase) was formed in the Ti40Zr40Ni20 rod; the microstructure of Ti40Zr40Ni20 ribbons mainly consisted of the I-phase. The solidification mechanism of the I-phase was different in the two alloys. The I-phase in the quasicrystalline rod was formed by packet reaction while in the ribbons it was generated directly from the liquid. At room temperature, both samples had relatively high hardness and elastic modulus; the elastic modulus of the ribbons is 76 GPa, higher than the 45 GPa of the rod. The hardness of the ribbons was more than twice that of the rod.

Microstructure evolution and mechanical properties of high Nb–TiAl alloy/GH4169 joints brazed using CuTiZrNi amorphous filler alloy

A CuTiZrNi amorphous filler metal was fabricated and utilized for brazing high Nb–TiAl alloys and GH4169 superalloys. The microstructure and mechanical properties of the high Nb–TiAl/GH4169 joints brazed from 900 °C to 1020 °C temperature range were studied. Results showed that the high Nb–TiAl/GH4169 joints consisted of three zones. The interfacial microstructure of the joints was high Nb–TiAl alloy/Ti3Al + Al3(Ni, Cu)Ti2 + Al(Ni, Cu)2Ti/AlCu2(Ti, Zr) + (Ti, Zr)(Ni, Cu) + Ti2(Ni, Cu)/Cr-rich (Cr, Ni, Fe)ss + Ni-rich (Ni, Cr, Fe)ss/GH4169 alloy. The element diffusion between the substrates and the filler alloy was intensified as the brazing temperature increased, and the interfacial reaction layer thickened. At 960 °C, the joint exhibited a maximum shear strength which was approximately 241.9 MPa. At higher brazing temperatures, the excessive AlCu2(Ti, Zr) phase and coarse Ti2(Ni, Cu) deteriorated the joint properties due to their inherent brittleness.

Effect of Sc and Zr on recrystallization behavior of 7075 aluminum alloy

The static recrystallization behavior of 7075 aluminum alloy containing Al3(Sc,Zr) phase prepared by casting and the relationship between recrystallization behavior and mechanical properties were studied. The addition of Sc and Zr made the Sc–Zr–7075 aluminum alloy remain the most of fibrous structure and high-density dislocations formed in the extrusion process, resulting in the recrystallization fraction of the alloy decreasing from 35% to 22%, and the corresponding fraction of substructure increasing from 59% to 67%. The Sc and Zr effectively inhibited the recrystallization behavior of 7075 aluminum alloy mainly, which was attributed to the fact that the existence of fine and coherent Al3(Sc,Zr) phase (r = 35 nm, f = 1.8×10−3) strongly pined the dislocations and grain boundaries, preventing the dislocations from rearranging into sub-grain boundaries and from developing into high angle grain boundaries, and further hindering the formation and growth of recrystallized core of the alloy.

Metastable structures in magnetron sputtered W–Zr thin-film alloys

Binary W–Zr thin-film alloys with different metastable structures were prepared by dc magnetron co-sputtering of W and Zr targets in argon atmosphere on unheated and unbiased substrates. The effect of the elemental composition on the formation of different structures and phases was studied in a very wide range of 3–99 at.% Zr. The microstructure and properties of the films were related to the individual metastable structures prepared. We found that W-rich films with an α-W(Zr) solid solution structure can be prepared in much wider range of the elemental composition (up to 24 at.% Zr) than indicated in the equilibrium W–Zr phase diagram. These films exhibited an enhanced hardness (up to 16.1 GPa) and a reduced residual stress (down to −0.05 GPa). Amorphous W–Zr films with a very low surface roughness (down to 0.4 nm) and metallic glass features were prepared with the Zr content between 33 and 83 at.%. The hardness of these films gradually decreased with increasing Zr content due to reducing average bond energy. All films were in the compressive state in contrast to the crystalline ones. The structure of crystalline Zr-rich films with higher than 88 at.% Zr was predominantly dual-phased exhibiting a gradual transition from a metastable β-Zr(W) solid solution (86–96 at.% Zr) through a metastable ω-Zr(W) solid solution (94–100 at.% Zr) to the thermodynamically stable α-Zr phase (99–100 at.% Zr) with increasing Zr (decreasing W) content. We also observed the formation of dual-phase glassy-crystalline structures in the transition zones between fully crystalline and glassy films.

Characteristics of microstructural and mechanical evolution in 6111Al alloy containing Al3(Er,Zr) nanoprecipitates

The evolution of microstructure and mechanical performances in 6111Al matrix alloy affected by trace amount of Er and Zr elements was thoroughly explored in this research work. Nanosized Al 3 (Er,Zr) particles with core-shell or hybrid structure owned perfect coherent relation with matrix Al, which acted as effective sites for the heterogeneous nucleation of α-Al. The average grain size was significantly refined from 147 ± 5 μm to 53 ± 2 μm in 6111Al-0.3wt%Er-0.1wt%Zr alloy. Besides, the precipitation behavior of the initial Mg 2 Si strengthening phase was also enhanced by these Al 3 (Er,Zr) dispersoids. Assisted by the cooperation of Grain refinement strengthening and Orowan strengthening etc., the yield strength, ultimate tensile strength and elongation of the alloy were high up to 289 MPa, 320 MPa and 12.9% respectively. A traditional hot rolling process has been conducted here to study the promotion and inhibition effect induced by Al 3 (Er,Zr) phases on recrystallization during deformation. The interaction among dislocations, grain boundaries and dispersoids was systematically and comprehensively revealed in this paper. • Properties of 6111Al improved a lot by combined addition of Er and Zr. • Al 3 (Er,Zr) dispersoids enhanced the precipitation behavior of Mg 2 Si phase. • Al 3 (Er,Zr) particles owned perfect coherent relation with matrix Al.