Binary Phase Research Articles

Structural, vibrational, and electrical study of the topological insulator PbBi2Te4 at high pressure

We report a joint experimental and theoretical study of the structural, vibrational, and electric properties of the topological insulator PbBi2Te4 under compression through X-ray diffraction, Raman scattering, and electrical measurements at high pressure, which are complemented with theoretical calculations that include the analysis of the topological electron density. The internal polyhedral compressibility of the rhombohedral phase, the behavior of its Raman-active modes, the electrical behavior, and the nature of its different bonds under compression are discussed and compared with their parent binary compounds and with related ternary materials. Interestingly, PbBi2Te4 retains its topological insulating properties as far as the rhombohedral tetradymite-like phase is retained under compression, unlike other tetradymite-like compounds. In addition, PbBi2Te4 undergoes an unconventional reversible pressure-induced decomposition into the high-pressure phases of its parent binary compounds (PbTe and Bi2Te3) above 8 GPa. Finally, we discuss that the intralayer bonds in the tetradymite-like structure of PbBi2Te4 are electron-deficient multicenter bonds; i.e. bonds of the same kind as those present in its parent binary compounds, in related chalcogenides, such as SnSb2Te4, and in general in chalcogenide-based phase change materials. These unconventional bonds are intermediate between covalent and metallic bonds and provide exceptional properties to the materials.

OBTAINING AN ACTIVE INGREDIENT FOR COTTON SEED TREATMENT BASED ON METHYLENDIUREA AND PARAAMINOBENZOIC ACID AND STUDYING ITS PHYSICOCHEMICAL CHARACTERISTICS

Seed treatment is the main method of protecting plants from infectious diseases. The article presents data on the production of a double compound based on methylene diurea and paraaminobenzoic acid and the study of its physicochemical characteristics. The chemical interaction in the three-component water-salt system methylenediurea (MDU) – para-aminobenzoic acid (PABA) – water was studied using the isothermal method of physicochemical analysis. The crystallization region of the new binary compound, the active substance, was established at a molar ratio MDU: PABA = 1:2. The formation of the double compound is confirmed by X-ray phase and IR spectroscopic methods of analysis. From the obtained X-ray phase analysis data, it follows that the reference lines of the double compound and their intensity differ from the X-ray patterns of the initial components. The IR spectra of MDM and PABA are characterized by intense absorption in the region of 3500-3390 cm-1 , 2000-500 cm-1 and 3500-3345 cm-1 , 1800-500 cm-1 , respectively. In the IR spectra of the new double compound MDM•2PABA, the absorption intensity in the region of 1800-500 cm-1 increases. A decrease in the absorption region of the stretching vibration of CO groups from 1626, 1626.3 cm-1 to 1612 cm-1 is observed in the case of the double compound MDM•2PABA. The results of the studies indicate the formation of a new compound. It is shown that the double compound has low hygroscopicity under summer, autumn, spring and winter storage conditions, high swelling and moisture capacity, and low solubility.

Experimental investigation and thermodynamic description of the Ni-Mo-Y ternary system

Nickel-based superalloys are extensively utilized in aerospace engines, marine gas turbines, and other environments with severe operating conditions. The phase relations of the Ni-Mo-Y ternary system were experimentally studied across the entire composition range at 800 °C and 1000 °C using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Thirteen three-phase regions were confirmed at 800 °C, and eleven three-phase regions were observed at 1000 °C. No ternary compound was observed at these temperatures. In addition, the experimental results indicate that molybdenum (Mo) has almost no solubility in the binary compounds found in the Ni-Y binary system. Furthermore, the primary solidification phases and the solidification process of typical alloys were investigated, and three different primary solidification phases were found. Based on the experimental results, thermodynamic calculations for the Ni-Mo-Y system were performed through the CALPHAD technique. The experimental results agree well with the calculated, a set of self-consistent thermodynamic parameters for the Ni-Mo-Y ternary system was obtained in the present work.

Thermodynamic phase equilibria of binary SF6–N2O hydrates and their structural analysis for the hydrate-based greenhouse gas capture

The increasing greenhouse gas (GHG) emissions from industrial activities have driven the development of efficient and environmentally safe GHG capture technologies. Clathrate hydrates, primarily composed of water, have attracted significant attention for their potential in GHG capture due to their ability to manage large emissions and their environmental advantages over materials like amine-based sorbents and metal-organic frameworks. This study investigates the hydrate-based capture of SF6 and N2O, two potent GHGs, to develop an effective GHG capture process. Phase equilibrium measurements demonstrate that binary SF6-N2O hydrates can form under moderate thermodynamic conditions, even with a small proportion of SF6, highlighting the feasibility of using hydrate-based methods to capture GHG mixtures. Furthermore, the formation of binary SF6-N2O hydrates enhances GHG volumetric storage capacity compared to pure SF6 hydrates. The guest compositions calculated for each binary SF6-N2O hydrate phase, along with spectroscopic analyses (Powder X-Ray Diffraction and Raman spectroscopy), confirm that the high GHG uptake in binary hydrates results from N2O molecules occupying the small cages of structure II hydrates, which are inaccessible to the larger SF6 molecules. These findings suggest that both the small and large cages of sII hydrates can be practically utilized for efficient capture of GHG mixture (SF6 and N2O) under mild conditions, thereby increasing the storage density of GHGs within the hydrate structure.

Contribution of bismuth melts to gold endowment in the Baolun gold deposit, Hainan Island, South China

Bismuth (Bi) melts and related polymetallic alloys can efficiently scavenge gold (Au) from Au-unsaturated aqueous solutions, contributing to the Au endowment in many hydrothermal deposits. However, original evidence for Au–Bi melts is often poorly preserved due to post-precipitation alteration. This complicates investigation of the liquid bismuth collector model in hydrothermal Au deposits. Here we present primary evidence for the occurrence of Au–Bi melt in hydrothermal systems through an examination of the Au–Bi phases and textures in the Baolun Au deposit (Hainan Island). This study found that maldonite, native bismuth, Au–Bi symplectite and Au–Bi melt blebs appeared successively following the precipitation of native gold. Notably, large Au–Bi melt blebs were well preserved in natural systems due to the rapid cooling of fluids. The mineral assemblages and their corresponding fluid physiochemical conditions suggest that the evolution of the ore fluids at Baolun was characterized by a continuous reduction in Au and Bi concentrations and Au/Bi ratios alongside decreasing fluid temperatures and sulfur fugacity (fS2). These observations offer direct evidence for Au scavenging by Bi melts in a mesothermal (275–450 °C), low-fS2 and reduced hydrothermal system, aligning well with the Au–Bi binary phase evolution established in metallurgy. As the fluid cooled further, the Au–Bi phases were subsequently overprinted by later Te–S-rich fluids, as evidenced by the formation of bismuthinite, jonassonite, and joséite-A around the Au–Bi phases. Importantly, our study reveals that the Baolun Au deposit ischaracterizedby a Au–Bi–Te hydrothermal system and that the metamorphic country rocks at Baolun are the major source of Au, Bi, and Te.

Crystal Structure Determination from Powder Diffraction Patterns with Generative Machine Learning.

Powder X-ray diffraction (PXRD) is a cornerstone technique in materials characterization. However, complete structure determination from PXRD patterns alone remains time-consuming and is often intractable, especially for novel materials. Current machine learning (ML) approaches to PXRD analysis predict only a subset of the total information that comprises a crystal structure. We developed a pioneering generative ML model designed to solve crystal structures from real-world experimental PXRD data. In addition to strong performance on simulated diffraction patterns, we demonstrate full structure solutions over a large set of experimental diffraction patterns. Benchmarking our model, we predicted the structure for 134 experimental patterns from the RRUFF database and thousands of simulated patterns from the Materials Project on which our model achieves state-of-the-art 42 and 67% match rate, respectively. Further, we applied our model to determine the unreported structures of materials such as NaCu2P2, Ca2MnTeO6, ZrGe6Ni6, LuOF, and HoNdV2O8 from the Powder Diffraction File database. We extended this methodology to new materials created in our lab at high pressure with previously unsolved structures and found the new binary compounds Rh3Bi, RuBi2, and KBi3. We expect that our model will open avenues toward materials discovery under conditions which preclude single crystal growth and toward automated materials discovery pipelines, opening the door to new domains of chemistry.

Self-assembly and energy storage potentials of biphasic phase change azobenzene liquid crystalline block copolymers

Flexible polymeric materials with potentials in energy storage have attracted extensive attention in today's sustainable society. Here, we reported a series of crystalline-liquid crystalline biphasic phase change block copolymers, poly(ethylene oxide)-b-poly(11-(4-(4-cyanophenylazo)phenoxy)undecane methacrylate) (PEO-b-PMAAzo), and studied the UV and Li+ ions coordination-mediated self-assembly for the potentials in phase change energy storage and solid electrolytes. The PEO-b-PMAAzo BCPs possess both the solid-liquid phase transition of PEO and the photo-chemical-thermal energy transition of PMAAzo block. Meanwhile, PEO has the capability to coordinate with the Li+ for the ionic conductivity. We explored the binary phase change behaviors and thermal energy density of the BCPs with different lithium ion concentrations before and after UV irradiation. The addition of LiTFSI salts increases the interaction parameters (χ) of the BCPs leading to phase transition of the self-assembled nanostructures. The phase diagram covering LAM, HEX, GYR, Fddd and HPL nanostructures facilitating ion transport was demonstrated. The PMAAzo block enabled the solid feature of the BCPs and ensured the high energy density and high conductivity. This work demonstrates that the combination of the functional polymers in one BCP not only provides multiple morphology tunabilities but also enables multiple functionalities from energy conversation and storage to ionic conductive electrolytes.

Direct mechanochemical synthesis of nano-LiAlH4 promoted by 0.696 wt% TiCl4 catalyst surface-modified Al powder

LiAlH4, known for its high hydrogen capacity and metastable nature, is a promising hydrogen source under mild conditions. However, its reversible regeneration from stable binary dehydrogenation phases (LiH/Al) is thermodynamically and kinetically hindered. By constructing a homogeneous and highly dispersed molecular layer of TiCl4 on the surface of the Al reactant to enhance the kinetics of the multiphase interfacial reaction, we achieved the direct mechanochemical synthesis of nano-LiAlH4, bypassing the intermediate phase Li3AlH6. Using the strong Lewis acidity of Ti4+, TiCl4 was chemically adsorbed onto the surface of the Al powder through Ti-O-Al bonds, with a loading capacity of only 0.696 wt%. The obtained TiCl4 surface-modified Al powder and LiH were hydrogenated by ball milling for 10 h under hydrogen pressure to synthesize nano-LiAlH4, which was then dehydrogenated at room temperature. This indicates that the crucial effects of the catalytic sites were dispersed on the reactant surface to ensure the local environment of the multiphase absorption/desorption hydrogen reaction interface and promote the reaction kinetics.

Experimental and numerical investigation on the performance of binary solid-solid phase change materials with integrated heat pipe and aluminium foam based heat sink for thermal management of electronic systems

Phase change material (PCM) is widely utilised in thermal management systems (TMS), however its low thermal conductivity inhibits performance. Heat pipe and porous materials are incorporated into PCM due to their high thermal conductivities to form a hybrid system that substantially enhances PCM's heat transfer capability. This study investigates experimentally and numerically, the cooling performance of heat sink by integrating aluminium foam and heat pipe (HP) with binary Neopentyl glycol (NPG)/Trihydroxy methyl-aminomethane (TAM) solid-solid phase change material (SS_PCM) obtained at 90/10 wt% (N9T1), 70/30 wt% (N7T3) and 50/50 wt% (N5T5). Compared to pure NPG thermal conductivity, N9T1, N7T3, and N5T5 samples demonstrated relative enhancement ratios of 0.017, 2.46, and 2.84. Different heat sink configurations are examined at three constant power levels 15, 17 and 19 W for the same charging period of 10000 s to determine the optimal cooling arrangement. During the charging period, hybrid cooling (PCM-Foam-HP) system with fan in contrast to an empty sink achieved the highest temperature reduction of 58.31 %, 58.99 % and 59.89 % at power levels of 15, 17 and 19 W, respectively. N9T1, N7T3 and N5T5 combinations lowered temperature by 4.6 %, 5.9 % and 10.8 %, respectively, when compared to NPG. Furthermore, all configurations performed better at lower heat generation rates by extending the safe operational period (SOP).The investigation concluded that N5T5 SS_PCM-aided heat sinks with integrated aluminium foam and heat pipe with fan reduced temperatures the most and performed best in all aspects. Finally, the experimental results for TMS were numerically validated using COMSOL software.

Effect of laser remelting treatment on the tribological properties of plasma sprayed WC–Cr3C2–Ni reinforced NiCrBSi coatings

The incorporation of single hard phases, such as tungsten carbide (WC), and chromium carbide (Cr3C2), into NiCrBSi coatings effectively enhances their performance, thereby fulfilling the tough requirements of high-temperature friction condition. To investigate the collaborative reinforcing effect of multiple hard phases and further enhance the high-temperature wear resistance of the coating, a novel WC–Cr3C2–NiCrBSi binary hard phase reinforced coating was developed and subjected to laser remelting treatment. The as-sprayed coatings demonstrate a distinct lamellar structure that diminishes upon remelting, resulting in significant densification of the coatings and a reduction in porosity to 0.3 %. The microhardness of the remelting coatings is reduced by about 10 % due to dilution of the coating by the lower hardness of the base material. However, during the laser remelting process, WC and Cr3C2 decompose and dissolve into the alloying binder phase of the coating, serving as solid solution agents. In cases where the concentration of W elements is elevated, a considerable precipitation of W-rich carbide is observed within the coating. Notably, N30 coatings demonstrate remarkable were resistance at both ambient and 700 °C, resulting in a significant reduction in wear volume by 86.5 % and 55.2 % respectively in comparison to original NiCrBSi coatings. The remelting treatment enhances the densification of the coating, improves the homogeneity of the microstructure, and reduces the coefficient of friction of the coating. The laser-remelted coating exhibits a decreased wear volume, attributed to a transition in its wear mechanism from fatigue-dominated to abrasive wear at room temperature. Conversely, under frictional conditions at 700 °C, the remelted coating experiences an augmented wear volume, attributed to severe abrasive wear.

Reasonable design of PBA-derived interfacial modified ternary compounds and hollow structure materials in high-performance asymmetric supercapacitors

Prussian blue analogues (PBA), common metal-organic frameworks (MOFs), are typically binary metal compounds. In this study, chromium was incorporated during the preparation of nickel‑cobalt PBA, resulting in the adjustment of the micro-morphology of PBA and the synthesis of small-sized PBA (sPBA) electrode materials with diameters ranging from 20 to 30 nm. These materials underwent various interfacial modifications to yield ternary metal phosphide (sPBA-P) and hollow nanostructures (sPBA-C). Additionally, by integrating graphene oxide (GO) as the growth substrate, successful preparation of GO@sPBA-P and GO@sPBA-C electrode materials was achieved. Significantly, these materials showcase outstanding electrochemical properties and interesting interfacial reactions when employed as cathode and anode components. Through a comprehensive series of characterization analyses, the electrochemical properties and reaction mechanisms of these materials were thoroughly investigated. Ultimately, an asymmetric supercapacitor (ASC) was assembled using the synthesized GO@sPBA-P and GO@sPBA-C to explore the material's potential in energy materials applications.

Electrochemical stability of biodegradable Zn-Cu alloys through machine-learning accelerated high-throughput discovery.

Zn-Cu alloys have attracted great attention as biodegradable alloys owing to their excellent mechanical properties and biocompatibility, with corrosion characteristics being crucial for their suitability for biomedical applications. However, the unresolved identification of intermetallic compounds in Zn-Cu alloys affecting corrosion and the complexity of the application environment hamper the understanding of their electrochemical behavior. Utilizing high-throughput first-principles calculations and machine-learning accelerated evolutionary algorithms for screening the most stable compounds in Zn-Cu systems, a dataset encompassing the formation energy of 2033 compounds is generated. It reveals that most of the experimentally reported Zn-Cu compounds can be replicated, especially the structure of R32 CuZn5 is first discovered which possesses the lowest formation energy of -0.050 eV per atom. Furthermore, the simulated X-ray diffraction pattern matches perfectly with the experimental ones. By formulating 342 potential electrochemical reactions based on the binary compounds, the Pourbaix diagrams for Zn-Cu alloys are constructed to clarify the fundamental competition between different phases and ions. The calculated equilibrium potential of CuZn5 is higher than that of Zn through the forward reaction Zn + CuZn5 ⇌ CuZn5 + Zn2+ + 2e-, resulting in microcell formation owing to the stronger charge density localization in Zn compared to CuZn5. The presence of chlorine accelerates the corrosion of Zn through the reaction Zn + CuZn5 + 6Cl- + 6H2O ⇌ Cu + 6ZnOHCl + 6H+ + 12e-, where the formation of ZnOHCl disrupts the ZnO passive film and expands the corrosion pH range from 9.2 to 8.8. Our findings reveal an accurate quantitative corrosion mechanism for Zn-Cu alloys, providing an effective pathway to investigate the corrosion resistance of biodegradable alloys.

Synergistic Effect Mechanism of Binary Sweet Taste Compounds.

In our previous study, phloridzin, sucrose, l-alanine, and dulcitol presented synergistic effects in Camellia nanchuanica black tea (NCBT). This study aims to verify the synergistic effects of the aforementioned sweet taste compounds and the mechanism involved. By conducting σ-τ plot analysis, phloridzin at the recognition threshold concentration (phl) exhibited synergistic effects with different concentrations of sucrose (Lsuc-6suc). Various concentrations of sucrose, phloridzin, and their combinations were selected to investigate the impact on sweet taste receptor cells. The results revealed that sucrose/phloridzin significantly increased the calcium signal compared to phloridzin and sucrose alone, attributed to the greater stability of the sucrose/phloridzin combination when binding to Taste 1 Receptor Member 3 (TAS1R3; one subunit of sweet taste receptor proteins). Ultimately, the sweet taste signal of sucrose/phloridzin was transmitted to the brain, triggering the activation of more brain regions associated with sweet taste perception (right insular, postcentral, and amygdala).

CaLi2PN3 - A Quaternary Chain-Type Nitridophosphate by Medium-Pressure Synthesis.

Nitridophosphates are in the focus of current research interest due to their structural versatility and properties, such as ion conductivity, ultra-incompressibility and luminescent properties when doped with suitable activator ions. Multinary representatives often require thorough investigation due to the competition with the thermodynamically more stable binary and ternary compounds. Another point of concern is the synthetic control of structural details, which is usually limited by conventional bottom-up syntheses. In this study, we report on the synthesis and characterization of the quaternary nitridophosphate CaLi2PN3. Various synthesis protocols were used for the preparation of CaLi2PN3, including the novel nitridophosphate double salt approach. The crystal structure was solved and refined from single-crystal X-ray diffraction data and confirmed by Rietveld refinement, solid-state NMR spectroscopy, EDX measurements and low-cost crystallographic calculations. The experimental results were corroborated by DFT calculations, which revealed the electronic band structure. Formation energy calculations allowed conclusions to be drawn about the stability in comparison to the initial ternary nitridophosphates. The synthesis of CaLi2PN3 exemplifies the enormous potential of medium-pressure syntheses in the field of nitridophosphate research. Furthermore, the presented new synthesis route allows a certain degree of structural control, which is a promising addition to previous synthesis strategies in nitridophosphate chemistry.

Topology of Intermetallic Crystals: Classification, Uniformity, and Transitions.

We have analyzed the crystal structures of 7551 binary intermetallic compounds, which are deposited in the inorganic crystal structure database, using a combined geometrical-topological approach as implemented in our program package ToposPro. We represented each crystal structure with two models: (i) the topological model of periodic atomic net and (ii) the geometrical model of the Voronoi partition of crystal space. Within the former model, we have classified all intermetallics into 949 topological types, 20 of which cover 57% of the whole sample. Using our recently developed topological network model of reconstructive solid-state transformations, we have described possible mechanisms of displacive transitions between the most abundant topological types and revealed a key role of the body-centered lattice in these transitions. The Voronoi partition model enabled us to introduce the concept of uniformity of the overall structure and the environment of separate atoms; the uniformity is estimated by the second moment of inertia of atomic Voronoi polyhedra. We have shown that the structures with a low uniformity value either contain mistakes in the crystallographic data or have significantly directed interatomic bonds. The proposed uniformity criteria can serve for the estimation of the robustness of an intermetallic structure.

Digital Modulator using Digitally Programmable Complementary metal–oxide–semiconductor Differential Voltage Current Conveyor

This study aims to Developing a digital modulation system using a new technology and idea, which is the digitally programmable CMOS (Complementary metal–oxide–semiconductor), Integrate the CMOS DVCC circuit as a modulator in the communication systems, as will be explained in chapter 3, Finally, simulate this new idea in communication by using a simulation program, which is PSpice software, and analyzing the results. By focusing on How to use digital programmable CMOS (Complementary Metal–Oxide–Semiconductor) in a communication system as a digital modulator, Verifying the effectiveness of the study using simulation software such as PSpice and MATLAB, and Analyzing and verifying the effectiveness of the three modified modulation techniques. Digitally programmable Binary Amplitude shift keying (DP BASK), Digitally programmable Binary Phase shift keying (DP BPSK), And Digitally programmable Binary Frequency shift keying (DP BFSK). This study adopts an applied research approach. The study demonstrated that the CMOS DVCC circuit could be successfully integrated into communication systems as a digital modulator. The study recommended to conduct further research on the noise resistance capabilities of the DP modulation techniques, and explore additional modulation techniques that could benefit from digitally programmable CMOS technology, such as Quadrature Amplitude Modulation (QAM) or Orthogonal Frequency-Division Multiplexing (OFDM).

Stability and Electronic Properties of K‐Sb and Na‐Sb Binary Crystals from High‐Throughput Ab Initio Calculations

AbstractThe study of the fundamental properties of alkali antimonide photocathodes for particle accelerators is currently hindered by the limited purity of the samples. First‐principles studies can effectively complement experiments to gain insight into the stability and the electronic structure of these compounds. In this high‐throughput analysis based on density‐functional theory (DFT), two families of binary crystals with K‐Sb and Na‐Sb compositions expected to form during evaporation of multi‐alkali antimonide photocathodes are investigated. Starting from an initial pool of structures mined from existing computational databases, automatized routines included in the in‐house developed library aim2dat are employed to determine the stability and the electronic properties of the aforementioned systems. By analyzing the formation energy, the structures are ranked in a convex hull retaining the information of their crystalline arrangement. Next, the band structure and the projected density of states of selected stable compounds are analyzed. Adopting the r2SCAN functional for the DFT calculations, reliable estimates of the character and size of the bandgaps are obtained and discussed in relation to the relative alkali content in the crystals. These results provide useful indications to predict and characterize binary phases forming during the growth of multi‐alkali antimonide photocathodes.

Acoustic Metasurfaces for Efficient Modulation and Demodulation of OAM Multiplexed Signals in Acoustic Communication

Abstract Orbital angular momentum (OAM) multiplexing has been suggested as a potential solution to increase the data capacity of acoustic communication systems. A method of modulation and demodulation of OAM multiplexed signals using acoustic metasurfaces is proposed in this manuscript. The amplitude and phase of independent acoustic orbital angular momentum (AOAM) multiplexed signal provide orthogonal degrees of freedom. By designing appropriate acoustic metasurfaces and combining them with binary differential phase coding techniques, we demonstrated that efficient modulation and fast demodulation of AOAM multiplexed signals can be achieved. Orthogonal acoustic spiral modes prevent mode coupling and crosstalk, enhancing acoustic multiplexing. The resonance-based structure provides signal frequency selectivity, boosting efficiency and simplifying terminal equipment for practical applications, which leads to the creation of high-capacity acoustic communication systems.

Diffusion and marker experiments for the newly discovered CuIn2 compound

Herein, CuIn2 is not identified as a stable phase in the CuIn binary phase diagram. However, several studies have reported the existence of CuIn2 at low temperatures. In this study, an electroplating process was used to examine the solid-state interfacial reactions between indium and copper. An indium layer with a thickness of 50 μm was electroplated onto a 1 mm thick Cu substrate at 25 °C, and the resultant Cu/In diffusion couples were subjected to aging processes at 60 °C, 80 °C, 100 °C, and 120 °C for up to 1000 h. These findings indicate that both CuIn2 and Cu11In9 phases were formed at 60 °C, 80 °C, and 100 °C, whereas only the Cu11In9 phase was detected at 120 °C. The growth kinetics of the Cu/In intermetallic compounds adhered to a parabolic law, implying that the reactions were governed by diffusion-controlled mechanisms. The utilization of a Ta diffusion marker in the experiments revealed that indium acts as the predominant diffusing species within the CuIn2 intermetallic compound.

Effect of lanthanum oxide on microstructure and mechanical properties of ZK60 magnesium alloy

Different amounts of La2O3 were added to ZK60 alloy to observe the changes in microstructure and mechanical properties of ZK60-XLa2O3 (X = 0, 0.2 wt%, 0.5 wt%) composites. Our findings reveal that within the as-cast ZK60 alloy, the Mg-Zn binary phase is manifested as rod-shaped precipitates, exhibiting a dispersed distribution predominantly along the grain boundary regions. With the increase of La2O3 addition, the rod-like Mg-Zn binary phases are gradually replaced by Mg-Zn-La ternary phases, and these Mg-Zn-La ternary phases are semi-continuously distributed around the grain boundaries. Both ZK602 and ZK605 alloys result in a corresponding improvement in ductility after extrusion. It is noteworthy that the ductility of the as-extruded ZK605 alloy is increased by 59.4% compared to ZK60 at the expense of a reduction of only 3.9% in yield strength. Taken together, the significant increase in ductility of ZK605 is mainly due to the weakening of the basal texture, which is weakened by the redox reaction of La2O3 with the α-Mg matrix, generating the La element. The decrease in yield strength of ZK605 in the extruded state is closely related to the observed grain coarsening phenomenon and the basal texture weakening. At the same time, the ultimate tensile strength of ZK605 shows a slight increase, which is mainly due to the second phase strengthening. The Mg-Zn-La ternary phase exhibits a notably hard character, and it is evident that the distribution of this phase becomes progressively denser as the La2O3 content increases.