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The interface properties of CeAlO3 (110)/NbC (111) were calculated by the first-principles and the refinement of CeAlO3 on NbC in hypereutectic Fe–Cr–C–Nb hardfacing alloy was demonstrated by experiments. The calculation results show that the mismatch of CeAlO3 (110)/NbC (111) is 7.2%, which indicates that the interface between CeAlO3 (110) and NbC (111) is a semi-coherent interface. Then, 11 layer CeAlO-terminated CeAlO3 (110) surface was selected to build interface with NbC (111) surface, whose surface energy is 0.380 eV/Å2. Because of the instability of O-terminated CeAlO3 (110) surface, its surface energy cannot achieve convergence. 6 kinds of interfaces between CeAlO3 (110)/NbC (111) were constructed, in which, interface-3 is the most stable with strong ionic and covalent bonds. Theoretically, CeAlO3 can act as the heterogeneous nucleation site for NbC. The experimental results show that the (Cr, Fe)7C3, NbC and γ-Fe phases exist in hypereutectic Fe–Cr–C–Nb–CeAlO3 hardfacing alloys. When CeAlO3 was added into the alloy, NbC can be refined. [ABSTRACT FROM AUTHOR]

In this study, a heterogeneous lamellar structure is achieved in Mg 97 Y 2 Zn 1 alloy via large-ratio hot extrusion of the alloys in as-cast (CE) and as-annealed (AE) stages. The ultimate tensile strength (UTS) of CE and AE alloys is 426.5 and 471.4 MPa, and their fracture elongation (FE) is 8.1% and 1.0%, respectively. Mechanical properties of the CE and AE alloys exceed that of the majority of wrought Mg 97 Y 2 Zn 1 alloys due to the heterostructure induced strengthening. Both in the two extruded alloys, α-Mg layers and LPSO layers acting as soft and hard domains, respectively, constitute the heterogeneous lamellar structure. As a result of the narrower spacing of α-Mg and LPSO layers, more refined DRX grains and LPSO particles, and the increased volume fraction of LPSO phase, the strength of the AE alloy is higher than that of CE alloy. However, the AE alloy exhibits poor ductility owing to the easy aggregation of dislocations and stress at the interfaces of narrower layers. Based on discussion of the strengthening mechanisms, the preparation of Mg 97 Y 2 Zn 1 alloys with tailored mechanical properties of high UTS ranging from 420 to 480 MPa, and FE 1∼ 8%, could be realized via the combination of annealing (controlling the content of 14H phase) and large-ratio hot extrusion (promoting the formation of heterogeneous lamellar structure). • Heterogeneous lamellar structure is achieved in blocky LPSO containing Mg 97 Y 2 Zn 1 alloys through large-ratio hot extrusion. • Compositions of the heterogeneous lamellar structure in the extruded Mg 97 Y 2 Zn 1 alloys were detailedly characterized. • Effect of heterogeneous lamellar structure and its spacings on the mechanical properties was discussed. • Controllable preparation of mechanical properties of Mg 97 Y 2 Zn 1 alloys proved can be realized via adjusting layer spacings. [ABSTRACT FROM AUTHOR]

Among various types of microstructures in titanium alloys, martensitic microstructure has the highest strength, but with poor ductility, which restricts its applications in the engineering practice. In this study, we have efficiently refined the martensite lath width from 500-1000 nm to 50–200 nm through 5% copper alloying in the Ti6Al4V alloy through laser powder bed fusion. The strength of the material increased from 1090 MPa of Ti6Al4V to 1460 MPa of Ti6Al4V5Cu with the elongation of 11.2%. The nanocrystalline lathy Ti6Al4V5Cu alloy prepared in this study can provide reference for the material design of new ultra-high strength titanium alloys. [ABSTRACT FROM AUTHOR]

High alloying elements effectively strengthen zinc alloys, but these elements also usually decrease the ductility and corrosion resistance of such alloys. In the present study, energy-saving and efficient rotary-die equal-channel angular pressing (ECAP) was successfully applied to a zinc alloy with a low Mg content (0.1 wt%) at room temperature (RT), which facilitated the formation of a microstructure with a fine grain size (1.14 ± 0.22 µm), weak texture, and dynamically precipitated nano-sized Mg-Zn precipitates at the grain interior. The Zn-0.1Mg alloy formed via RT-ECAP exhibited an outstanding performance, with a high ultimate tensile strength of 383 MPa, excellent ductility of 45.6 %, and a suitable biodegradation rate of 0.014 mm/y in Hank's solution. This alloy is thus a promising candidate for various biodegradable medical applications. [Display omitted] • Severe plastic deformation of ECAP is realized in a Zn-0.1Mg (wt %) alloy at room temperature. • The room temperature ECAP alloy exhibits both outstanding mechanical properties and biodegradable performance. • The effect of processing temperature on microstructure and property evolutions of ECAP alloy is revealed. [ABSTRACT FROM AUTHOR]

In this study, equal channel angular pressing (ECAP) was employed as a technique to gradually increase the input of strains on Zn-xCu (x = 2, 3; wt%) alloys and investigate their work softening behavior. The microstructure and mechanical properties of Zn–Cu alloys with various processing strains were systematically characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometer (XRD), electron back scattered diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests at room temperature. The results showed that besides η-Zn matrix refined via dynamic recrystallization (DRX), nano-sized precipitated CuZn 5 particles were formed in ECAP alloy. Compared with the as-cast alloy, the ultimate tensile strength (UTS) of 1P alloy (after 1 pass of ECAP) was significantly improved to 207 MPa. However, the UTS declined with further increasing ECAP numbers. The 12P alloy (after 12 passes of ECAP) exhibited low UTS of 114 MPa but with an obviously increased elongation of 121% (from 56% of 1P), indicating that the alloy had a softening behavior with increased plastic strains. The main reason for the decline of strength was attributed to the texture weakening, the lower contribution of solid solution strengthening caused by the growth of precipitated CuZn 5 phase. The higher ductility of 12P alloy was mainly ascribed from grain refinement, increased continuous DRX softening and the Zn/CuZn 5 phase boundary sliding. This work provides a promising insight into the improvement of softening behavior for Zn–Cu based alloys. [ABSTRACT FROM AUTHOR]

Banded structure with alternately arranged ultra-fine η-Zn + Mg 2 Zn 11 bands and ultra-fine η-Zn + CuZn 5 bands was obtained in Zn–3Cu–1Mg (wt.%) alloy after multi-pass equal channel angular pressing (ECAP). Owing to the effective heterogeneous deformation-induced (HDI) strengthening and hardening from soft η-Zn + CuZn 5 and hard η-Zn + Mg 2 Zn 11 domains, the ECAP alloys exhibited outstanding mechanical properties with ultimate tensile strength of 388–415 MPa, and fracture elongation of 29.2–63.0%. [ABSTRACT FROM AUTHOR]

Anisotropy of a 32-pass equal channel angular pressing (ECAP) processed Mg-3.7Al-1.8Ca-0.4Mn (wt%) alloy with synergistically enhanced mechanical properties and corrosion resistance was investigated. Compared with coarse α-Mg grains and discontinuous network Al 2 Ca phase in as-cast alloy, the ECAP alloy exhibits homogeneous fine α-Mg grains (~2.6 µm), but refined Al 2 Ca particles show different distribution in three planes, which is network in the extrusion plane (EP), uniform in normal plane (NP) and bandlike in transverse plane (TP). Refinement of microstructure after ECAP resulted in the synergistically enhanced mechanical and corrosion performances in three planes (directions). Moreover, due to grain refinement, the protective film was easily produced on the ECAP alloy, resulting in different corrosion mechanisms developed between ECAP and as-cast alloys. The main factors effecting anisotropic properties of ECAP alloy are Al 2 Ca distribution and texture of α-Mg. Based on the anisotropy investigations, grain size in several microns and high (0001) basal texture density are necessary to realize RE-free Mg-Al-Ca-Mn alloys with synergetic high strength and good corrosion performance. [Display omitted] • Corrosion and mechanical properties of a Mg-3.7Al-1.8Ca-0.4Mn ECAP alloy were enhanced in three-dimensional space. • Anisotropic microstructural evolution of ECAP alloy were investigated. • The anisotropy of corrosion mechanism of ECAP alloy were illustrated. • Main microstructure characteristics impacting anisotropic properties were expounded. • The way to realize Mg-Al-Ca-Mn alloys with strength-corrosion synergy was concluded. [ABSTRACT FROM AUTHOR]

• Zn-1.5Mg-0.3Y (wt%) alloy with high strength-ductility and good work-hardening ability was prepared by multi-pass ECAP. • ECAP tailored the size and distribution of microscale and sub-microscale YZn 12 particles. • Homogeneously refined microstructure, and texture deviated from basal plane were beneficial to improvement of ductility. • Twinning in both Zn matrix and refined sub-microscale YZn 12 phase contributed to work hardening ability. In this study, the effects of Y addition on microstructure and mechanical properties of Zn-Mg alloy during multi-pass equal channel angular pressing (ECAP) were systematically investigated. The results show that apart from α-Zn matrix and network-shaped eutectic Zn+Mg 2 Zn 11 structure, micron-sized and submicron-sized YZn 12 particles were formed in as-cast alloy. During multi-pass ECAP, the α-Zn matrix was refined via dynamic recrystallization (DRX), and the eutectic structure was fragmented into fine particles gradually, while the YZn 12 particles became further refined (~100 nm) only from 8p to 12p ECAP. Tensile tests at room temperature indicated that the 12p-ECAP alloy exhibits the optimal mechanical properties with ultimate tensile strength of 465 MPa and fracture elongation of 11%. The fine and uniform microstructure contributes to the enhancement of ductility. Furthermore, the improved work hardening ability of 12p alloy was mainly ascribed from the generation of submicron-sized YZn 12 particles with the size of ~100 nm, which could induce twinning with them and increase the density of geometrically necessary dislocations. The results suggest that the introduction of second phase particles with twinning ability may be effective to improve the work hardening ability of Zn alloys. [ABSTRACT FROM AUTHOR]

GH4169 alloy/Inconel 718 is extensively utilized in aerospace manufacturing due to its excellent high temperature mechanical properties. Micro-structuring on the workpiece surface can enhance its properties further. Through-mask electrochemical micromachining (TMEMM) is a promising and potential processing method for nickel-based superalloys. It can effectively solve the problem that traditional processing methods are difficult to achieve large-scale, high-precision and efficiency processing of surface micro-structure. This study explores the feasibility of electrochemical machining (ECM) for GH4169 using roll-print mask electrochemical machining with a linear cathode. Electrochemical dissolution characteristics of GH4169 alloy were analyzed in various electrolyte solutions and concentrations. Key parameters including cathode sizes, applied voltage and corrosion time were studied in the roll-print mask electrochemical machining. A qualitative model for micro-pit formation on GH4169 was established. Optimal parameters were determined through experiments: 300 μm mask hole and cathode size, 10 wt% NaNO3 electrolyte, 12 V voltage, 6 s corrosion time. The results demonstrate that the micro-pits with a diameter of 402.3 μm, depth of 92.8 μm and etch factor (EF) of 1.81 show an excellent profile and localization. [ABSTRACT FROM AUTHOR]

In this work, the microstructure evolution during superplastic deformation process and its impact on superplastic behavior of a peak-aged wrought Mg-10Gd-3Y-1.5Zn-1Zr (wt%) alloy were investigated by comparing the microstructure before and after high temperature tensile test (HTTT). The results show that except for the sample deformed at 400 °C with the strain rate of 1 × 10 −3 s−1, all the other samples exhibit superplasticity when deformed at temperatures between 400 °C and 475 °C with the strain rate from 1 × 10−3 s−1 to 5 × 10−3 s−1. The dominant superplastic deformation mechanism of the alloy is grain boundary sliding (GBS) controlled by grain boundary (GB) diffusion. In addition, three main changes of the microstructure are confirmed after HTTT compared with the peak-aged alloy, i.e., the disappearance of the Mg 3 Gd phase, the emergence of the Mg 24 Y 5 phase, and the various volume fraction of 14H long period stacking ordered (LPSO) phase. Moreover, when deformed at 450 °C with the strain rate of 5 × 10−3 s−1, this alloy obtains the highest superplastic elongation (972%). This is due to the largest number of precipitated 14H LPSO and Mg 24 Y 5 phases, as well as the fragmentation of the Mg 24 Y 5 particles, which can delay the grain boundaries separation and improve the ability of the microstructure to accommodate more dislocations. • The dominant superplastic deformation mechanism of peak-aged Mg-10Gd-3Y-1.5Zn-1Zr alloy is grain boundary sliding. • Evolutions of microstructure during high-temperature tensile test were characterized. • The sample deformed at 450 °C and 5 × 10−3 s−1 exhibits the highest superplastic elongation. • Dynamically precipitated phases improve the accommodation ability of microstructure for more dislocations. [ABSTRACT FROM AUTHOR]

In this study, the microstructure evolution and mechanical properties of Zn-0.6 (wt.%) Mg alloys with minor calcium (Ca) and strontium (Sr) additions (0.1 wt%) during multi-pass equal channel angular pressing (ECAP) were comparatively investigated. The obtained results illustrate that in addition to α-Zn matrix and network-shaped ternary α-Zn + Mg 2 Zn 11 + MgZn 2 eutectic structure, CaZn 13 and SrZn 13 particles are formed in as-cast Zn-Mg-Ca and Zn-Mg-Sr alloys, respectively. The CaZn 13 particles exhibit cuboid shape, and their sizes are much larger than the ellipsoidal SrZn 13 particles. After multi-passes ECAP, both α-Zn grains and eutectic structure are obviously refined owing to the dynamic recrystallization (DRX) process and mechanical crushing effect, while the CaZn 13 and SrZn 13 particles exhibit no obvious change. Moreover, the existence of cuboid CaZn 13 particles with sharp corners are more effective to refine α-Zn matrix via the particle stimulated nucleation DRX mechanism, resulting in finer microstructure of Zn-Mg-Ca alloy. Since the CaZn 13 particles could induce large stress concentration at their shape corners during deformation, which even causes crack of the particles in ECAP alloys, the ductility of Zn-Mg-Ca alloys is significantly deteriorated. Overall, the 12p ECAP Zn-Mg-Sr alloy exhibits optimal mechanical properties with ultimate tensile strength above 300 MPa and elongation higher than 20%. Nevertheless, the deformed Zn-Mg-Ca alloys possess poor ductility owing to the existence of CaZn 13 particles, which should be avoided in future design of Zn-based biodegradable metals. • CaZn 13 and SrZn 13 phases formed in Zn-Mg alloys with minor Ca and Sr additions, respectively. • CaZn 13 particles exhibited cuboid shape, and their sizes were much larger than ellipsoidal SrZn 13 particles. • Cuboid CaZn 13 particles with sharp corners were more effective to refine α-Zn grains. • CaZn 13 particles were cracked during ECAP, resulting in deteriorated ductility of Zn-Mg-Ca alloys. [ABSTRACT FROM AUTHOR]

• Mesoporous Ag-MA nanocomposites with Hg2+-enhanced catalysis were synthesized. • The nanocomposites have large surface-to-volume area and high aqueous stability. • Ag-MA nanocomposites could detect Hg2+ ions with concentration down to 0.025 nM. • Hg2+ ions in wastewater can be removed with the efficiency up to 99.76 %. • An absorption capacity of 598.99 mg g−1 can be expected for Hg2+ ions. Mesoporous silver-melamine (Ag-MA) nanocomposites were synthesized by controlled supramolecular self-assembly with various structural morphologies. It was discovered that the rod-like Ag-MA nanocomposites could present the larger Hg2+-enhanced catalysis by forming Ag-Hg alloys. Also, they could display large surface-to-volume area and high aqueous stability for the selective Hg2+ enrichment and absorption of Hg2+ ions by yielding the stable coordination complexes. A catalysis-based colorimetric method was thus developed using 96-wells plates to probe Hg2+ ions in blood and wastewater with the linear Hg2+ concentrations ranging from 1.0 nM to 600 nM and 0.50 nM to 700 nM, respectively. Besides, mesoporous Ag-MA absorbents could facilitate the removal of Hg2+ ions in wastewater with the removal efficiency up to 99.76 % and the absorption capacity of 598.99 mg g−1. [ABSTRACT FROM AUTHOR]

In this study, the Zn-1.6 Mg alloy was processed by multi-pass equal channel angular pressing (ECAP) at three different temperatures to investigate its microstructural evolutions and mechanical properties. The obtained results showed that the microstructure of the as-cast alloy consisted of α-Zn primary phase and a three-component eutectic structure: α-Zn + Mg 2 Zn 11 + MgZn 2. The α-Zn and Mg 2 Zn 11 phases exhibited typical rod eutectic morphology, and MgZn 2 nanoscale particles were precipitated within Mg 2 Zn 11 phase. Multi-pass ECAP stimulated dynamic recrystallization (DRX) of primary α-Zn grains and crush of eutectic structure gradually. High ECAP temperature accelerated the growth of α-Zn and Mg 2 Zn 11 grains, while MgZn 2 nanoscale particles showed no obvious growth owing to their good thermostability. Moreover, low temperature promoted the formation of a bandlike microstructure, while high temperature resulted in a homogeneous microstructure. Tensile tests demonstrated that the 12p ECAP alloy processed at 150 °C possessed the optimal mechanical properties with ultimate tensile strength of 423 MPa, yield strength of 361 MPa and elongation of 5.2%. The simultaneously enhanced strength and ductility could be ascribed to the combined effect of fine DRX grains, refined Mg 2 Zn 11 s phase particles, MgZn 2 nanoscale particles, and the precipitation of new MgZn nano-particles within α-Zn grains. • An α-Zn + Mg 2 Zn 11 +MgZn 2 eutectic structure formed in Zn-1.6 Mg cast alloy. • ECAP at different temperatures was performed on Zn-1.6 Mg alloy. • Refinement of α-Zn grains and three-component eutectic structure was discussed. • MgZn particles were dynamically precipitated within α-Zn grains during ECAP. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) are considered to be promising multifunctional electrocatalysts because of their diverse constituent elements, structural uniformity, and multiple active sites that can be applicable for various reactions. In this study, the Fe 20 Co 20 Ni 20 Cr 20 Mo 20 HEA was utilized as a substrate to rapidly synthesize a nanostructured porous film with a highly active HEA surface area via an electrochemical one-step dealloying method. The dealloyed HEA exhibited an excellent oxygen evolution activity, with a low overpotential of only 370 mV at 40 mA cm−2, which is lower than those of the commercial IrO 2 –RuO 2 –Ta 2 O 5 /Ti (500 mV) and IrO 2 –RuO 2 /Ti (542 mV) catalysts, and a Tafel slope of 119 mV dec−1. After synthesizing a nanostructured porous film through dealloying, the active surface area of the HEA increased by 30%. Following a 60-h stability test, the overpotential difference of the HEA before and after the stability test is less than 30 mV, signifying outstanding stability. The obtained results indicate that the prepared FeCoNiCrMo HEA is primarily composed of two phases, namely the σ phase and the face-centered cubic (FCC) phase. The uneven distribution of the corrosion-resistant element Cr in these phases resulted in significantly different corrosion rates for the two phases, wherein the FCC phase underwent preferential corrosion. Additionally, synergistic electronic coupling among the surface atoms of the nanostructured porous film further enhanced the oxygen evolution reaction (OER) performance. This electrochemical dealloying method demonstrated a high reproducibility and provided an effective pathway for optimizing OER catalysts. • Nanostructure was obtained on the dual-phase HEA surfaces via single-phase corrosion. • The uneven distribution of Cr led to divergent corrosion rates in the duplex phase. • The HEA after dealloying exhibited impressive oxygen evolution properties. [ABSTRACT FROM AUTHOR]

Aluminum–copper-based alloy has a broad liquidus to solidus temperature range, making it susceptible to the formation defects such as pores and shrinkage pores during the process of solidification. Hence, ultrasonic vibration and squeeze casting can help to refine the microstructure and eliminate the formation of pores. In this paper, we used an optical microscope, scanning electron microscope, transmission electron microscope, differential scanning calorimetry, and thermal analysis to study the ultrasonic treatment (UT) and squeeze casting (SC) on the as-cast and heat-treated microstructure of Al–Cu–Mn alloys. The results show that a significant refinement can be obtained by the compound field compared with that of the individual field. The applied UT time is 30 s and 120 s, respectively. The smallest grain size and the finest Al2Cu particles are observed in the alloy with a treated time of 120 s. This is due to the ultrasonic field breaking the dendrites and promoting the flow of molten Al; squeeze casting increases the cooling rate and stimulates the nucleation temperature of α-Al. The size of the θ′ phase after compound field treatment is smaller because more Cu atoms are dissolved in the Al matrix, so the θ' strengthening phase is finely dispersed in the Al alloy matrix. It is concluded that the compound field of UT and SC is a potentially advantageous process to refine the microstructure of Al alloys. [ABSTRACT FROM AUTHOR]

Zn–Ag alloys are promising biodegradable materials for clinical applications, but their mechanical properties are below the application requirements. In this work, a high-strength and high-ductility Zn–Ag alloy was achieved through trace (0.08 wt%) Mg addition and equal channel angular pressing (ECAP). Specifically, ECAP processed Zn-2.5Ag-0.08Mg alloy possesses a remarkably high ultimate tensile strength (UTS) and elongation (EL) of 393.1 MPa and 56.3%, respectively, far surpassing the application benchmark. The addition of Mg suppresses grain boundary sliding and thus delays the inverse Hall-Petch relation. The alloy features very fine grains of 1.23 μm, and grain boundary strengthening is the dominant strengthening mechanism. High-ductility is attributed to suppression of deformation twinning, activation of pyramidal slip, and low dislocation density. • A high-strength and high-ductility Zn-2.5Ag-0.08 Mg alloy was developed. • The strength and ductility of the alloy far surpasses the application benchmark. • Trace Mg addition delays the inverse Hall-Petch relation. • Grain boundary strengthening is the dominant strengthening mechanism. [ABSTRACT FROM AUTHOR]

The tension-compression asymmetric mechanical behavior of the AZ91 magnesium alloy with multi-heterogenous microstructure was investigated in comparison with its cast counterpart. The individual effect of different deformation modes in fine and coarse grains are clarified to reveal the underlying mechanism behind the asymmetric yield behavior by electron back-scatter diffraction analysis. The result demonstrated that the mechanical twinning prevailing in coarse grains is responsible for the yield asymmetry of the multi-heterogeneous alloy. [ABSTRACT FROM AUTHOR]

Highlights • A Mg 97 Y 2 Zn 1 wire was prepared via combined ECAP and drawing. • The wire exhibited ultimate tensile strength of 570 MPa and elongation of 12%. • Refined and dispersive 18R LPSO clusters contributed to the improved mechanical properties. Abstract A 0.31 mm-diameter Mg 97 Y 2 Zn 1 alloy wire with high yield strength of 550 MPa, ultimate tensile strength of 570 MPa and elongation of 12% was successfully prepared via the combination of ECAP and heavy drawing at elevated temperatures. Microstructure observation showed that the 18R phases were broken into fine particles and formed clusters during drawing of ECAP rod. The α-Mg matrix was refined via dynamic recrystallization, and the DRX grains were mixed with dynamically precipitated 14H particles. The ultra-fined microstructure, as well as the homogenous distribution of LPSO particles and clusters, contributed to the exceptional mechanical properties of Mg 97 Y 2 Zn 1 alloy wire. [ABSTRACT FROM AUTHOR]

Fe3O4/NiFe2O4 nanosheets as anode materials for lithium-ion batteries have been successfully prepared by a facile one-step dealloying method of Al-Fe-Ni alloy precursor. Herein, the XRD results and XPS spectra indicated that the product consists of cubic NiFe2O4 and Fe3O4. Scanning electronic microscopy and transmission electron microscopy images showed the homogenous distribution of Fe3O4/NiFe2O4 in the quasi-hexagonal nanosheets rather than irregular clusters. Besides nanostructures, their electrochemical performances were also enhanced due to the doping of nickel when comparing with the Fe3O4 obtained by dealloying Al-Fe precursor. Cycling and rate tests elicited the DAFN has the Fe3O4/NiFe2O4 product exhibit a higher initial capacity of ~ 1437 mAh g−1 at 200 mA g−1 and modified rate performances, especially they hold a doubled reversible capacity over 500 mAh g−1 after 750 times cycling at 200 mA g−1. Cyclic voltammetry, charge-discharge tests and electrochemical impedance spectra measurements further demonstrated the reinforced initial capacity and cycling stability of the DAFN could be associated with the shortened diffusion pathways and synergistic effect of Fe3O4 and NiFe2O4. The facile and low-cost processing method accompanied with the well-performed product exhibit a promising prospect in the application of lithium-ion storage. [ABSTRACT FROM AUTHOR]

Purpose: Alkali metal ablation is newly emerging as an effective, economic and minimally invasive ablation therapy. This study is dedicated to demonstrate the high efficiency of NaK alloy ablation on in vivo tumors with different stages in mice. Material and methods: Panc02 tumor cells were injected into 21 female C57B/L mice, which were divided into three groups. Two experimental groups of mice received the same percutaneous NaK alloy injection for a week apart. The inner temperature response and surface temperature distribution were measured using a thermal couple and an infrared camera. After each ablation experiment, two mice in each group were chosen randomly to make pathological sections. The tumor volumes were measured once every two days. At the end, all tumors were cut off to calculate the tumor inhibition rates. Results: The NaK alloy-induced ablation therapy produced an obvious temperature increase (85 °C) in the ablation region and the high temperature distribution was relatively concentrated. The histopathology sections showed that developing stage tumors received incomplete destruction of the malignant cells compared with early stage tumors. The tumor inhibition rate in the early and developing tumor treatment groups were 88.5% and 67.6%, respectively. Conclusions: This technology provides a nearly thorough ablation treatment for early stage tumors and also a palliative treatment for developing tumors. [ABSTRACT FROM AUTHOR]

In this study, Zn-xCu (-0.1 Mg) wires with a diameter of 0.3 mm were obtained by hot extrusion and cold drawing. The microstructures, mechanical properties, and degradation behaviour were investigated to evaluate their feasibility as biodegradable metals. During the drawing process of the Zn-xCu alloys, many granular CuZn5 phases were dynamically precipitated, and the grains were significantly refined, along with a significant work softening with the tensile strength decreasing and the elongation increasing (from 161 MPa to 92 MPa and 22%–103% for Zn-0.2Cu). With the increase of Cu additions, the phenomenon of work softening was more intense and there was an opposite trend in the strength changes between the as-extruded rods (increase) and as-drawn wires (decrease). With 0.1 wt.% Mg added, the stable rod-like Mg2Zn11 phase was formed in as-extruded Zn-xCu-0.1 Mg rods, which obviously improved the strength, and inhibited the dynamic precipitation of granular CuZn5 phase and work softening phenomenon in the drawing process (from 332 MPa to 313 MPa and 11%–46% for Zn-0.2Cu-0.1 Mg). In addition, due to the micro-galvanic effect induced by the precipitates, alloying accelerated the degradation of Zn alloy wires, especially Zn-1Cu-0.1 Mg, which was related to the shape, distribution, and potential of the phases. [ABSTRACT FROM AUTHOR]

Zn has garnered increasing attention in the realm of biodegradable materials due to its moderate degradation rate and no harmful gas released during degradation. However, the poor mechanical properties of Zn necessitate improvement by alloying and deformation processing. Currently, the primary studied Zn-based alloy systems include Zn-Mg, Zn-Li, Zn-Cu, Zn-Mn, Zn-Ag, and Zn-Ca alloys. Among these alloy systems, Mg is an essential element for the human body with advantages of low cost and good ability to enhance mechanical properties of Zn. Consequently, biodegradable Zn-Mg alloy exhibits fascinating application potential. This paper provides a comprehensive overview of research progress on Zn-Mg alloys by summarizing the effects of composition and deformation processing on degradation properties, biocompatibility, and mechanical properties. Additionally, this paper highlights existing challenges and hopes to offer new perspectives and ideas for researchers engaged in the study of degradable materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• An Al-6Si-3Cu cast alloy was transformed to a profile through room temperature rolling. • The solutionized Al-6Si-3Cu processed by room temperature rolling has a UTS of 429.8 MPa and an EL of 5.8%. • Subsequent aging significantly enhances the EL to 9.9% at a slight loss of UTS. Recent studies demonstrate that Al-Si alloys, which are conventionally used in as-cast form, can be transformed to profiles through high temperature plastic deformation. However, rare attention is paid to room temperature deformation of Al-Si alloys. In this work, an Al-6Si-3Cu alloy with excellent mechanical performance was produced through combined heat treatment and room temperature rolling, which is superior to other recently developed Al-Si alloys. Specifically, the alloy processed by a combination of solid solution treatment and room temperature rolling has an ultimate tensile strength (UTS) of 429.8 MPa and an elongation (EL) of 5.8%, exhibiting an improvement of 105% and 76% compared to the as-cast alloy, respectively. Subsequent artificial aging further enhances the EL to 9.9% but decreases the UTS to 387.4 MPa, which exceed that of the as-cast alloy by 200% and 85%, respectively. Detailed microstructure observations were performed to reveal the underlying mechanisms behind the enhancement of strength and ductility. Results presented in this work may shed some light on the development of strong and ductile Al-Si alloys. [ABSTRACT FROM AUTHOR]

The influence of precipitation on the intergranular corrosion sensitivity of Alloy 31 aged at 950 ℃ for 0–96 h was investigated by microstructure analysis and the modified double loop electrochemical potentiokinetic reactivation method. The results reveal that the kinetics of the primary precipitated sigma phase agree with the Yamamoto equation. The degree of sensitization increases rapidly to 4 h, then decreases to 8 h with self-healing, but no further self-healing occurs after that. The degree of sensitisation depends on the Cr and Mo-depletion zone neighbouring the precipitated sigma phase. [Display omitted] • The precipitation kinetics of the sigma phase agrees with the Yamamoto equation. • The intergranular corrosion sensitization is dependent on the Cr and Mo-depletion region induced by the sigma phase primarily. • The degree of sensitization increases rapidly to 4 h, then decreases to 8 h with self-healing, but no further self-healing occurs after that. [ABSTRACT FROM AUTHOR]

A comparative study on the microstructural evolutions and mechanical properties of as-cast and as-homogenized Mg-3.5Al-4.5Ca-0.4Mn (wt.%) alloys with different Mg 2 Ca morphologies during equal channel angular pressing (ECAP) is reported herein. The results showed that while the network Mg 2 Ca phases in the as-cast alloy were broken into ultrafine particles after multipass ECAP, they were still aggregated at original grain boundary regions. After homogenization, large spherical Mg 2 Ca particles, which were not refined but distributed uniformly through multipass ECAP, were formed. With an increase in ECAP passes, both aggregated ultrafine Mg 2 Ca particles and large spherical particles stimulated dynamic recrystallization (DRX). The ultrafine Mg 2 Ca particles introduced incomplete DRX with a finer α-Mg grain size, whereas the large spherical particles resulted in almost complete DRX with a coarser grain size after 12p-ECAP. Moreover, nano-sized acicular and spherical precipitates were dynamically precipitated during ECAP. Owing to the fine grain size, weak texture, ultrafine Mg 2 Ca particles, and nano precipitates, the 12p-ECAP cast alloy exhibited a high ultimate tensile strength of 331 MPa and moderate fracture elongation of 7.4%. The ECAPed homogenized alloys showed lower mechanical properties, which could be attributed to preexisting microcracks within Mg 2 Ca spherical particles that were introduced by homogenization. • Network-shaped Mg 2 Ca transformed to large spherical Mg 2 Ca particles after homogenization. • Mg 2 Ca network was refined into ultra-fine particles during ECAP. • Large spherical Mg 2 Ca particles were not further refined after ECAP. • Ultra-fine Mg 2 Ca particles contributed to finer DRX grains and higher strength. [ABSTRACT FROM AUTHOR]

Binary Zn–Mg alloys have great potential as biodegradable implants due to their good biological safety and moderate degradation rates. Herein, a new combined process of ECAP plus cold rolling of as-cast Zn–0.6Mg alloy was developed to address its application problem of insufficient mechanical properties and serious localized corrosion. Cold rolling process can break the eutectic phase and refine grains, while deformed grains were dominant with a lot of dislocations. 8-pass ECAP process can refine grains by recrystallization, and the grains were equiaxed with less dislocations. The strength and ductility were greatly improved after cold rolling (CR) or ECAP processing compared with that of as-cast alloy, but the strength still cannot meet the requirement of orthopedic implant materials. After 8-pass ECAP+CR75% (ER) processing, the strength was further improved, which benefited from fine grain strengthening, second phase strengthening, and strain strengthening mechanisms. Tensile yield strength (σ YS), ultimate tensile strength (σ UTS), and fractured elongation of ER alloy were 301.2 MPa, 411.8 MPa, and 28.5%, respectively, which can meet the requirement of orthopedic implants. The eutectic phase fragmentation and grain refinement caused by cold rolling and ECAP process can reduce the galvanic corrosion tendency of the Zn–0.6Mg alloy. The corrosion resistance was further improved after 8-pass ECAP+CR75% processing with the degradation rate of 0.025 mm/y, and the alloy tended to corrode uniformly. • A new combined process of ECAP plus cold rolling (CR) of as-cast Zn-0.6Mg alloy was developed. • 8-pass ECAP+CR75% processing can refine grains and break eutectic phase of Zn-0.6Mg alloy greatly. • The mechanical properties of 8-pass ECAP+CR75% processed Zn-0.6Mg alloy were superior in Zn-Mg alloys. • The 8-pass ECAP+CR75% processed Zn-0.6Mg alloy tended to corrode uniformly. [ABSTRACT FROM AUTHOR]

In this work, a bimodal grain structured Zn-0.4Mg-0.02Mn alloy with superior strength-ductility synergy was successfully prepared by combined equal channel angular pressing (ECAP) and cold rolling. The alloy has an ultimate tensile strength (UTS) of 334.4 MPa and an elongation (EL) of 40.0%, far exceeding the benchmark for medical implants. Hetero-deformation induced (HDI) strengthening plays a key role in its excellent mechanical performance. • A bimodal grain structured Zn alloy was obtained by combined ECAP and cold rolling. • The alloy shows superior strength-ductility synergy (UTS = 334.4 MPa, EL = 40.0%). • HDI strengthening plays a key role in the excellent mechanical performance. [ABSTRACT FROM AUTHOR]

Due to the low recrystallization temperature, the microstructure of wrought Zn alloys is naturally unstable, which affects their mechanical properties and limits their application. Therefore, it is crucial to elucidate the effect of microstructural evolution on mechanical properties of wrought Zn alloys. In this work, annealing treatment was performed on a Zn-0.5Cu (wt%) equal channel angular pressure (ECAP) alloy at 200 °C for different durations to investigate the microstructure evolution and its effect on the mechanical properties. An abnormal phenomenon that strength and ductility of the ECAP alloy decrease monotonically with increasing annealing time was observed, which is remarkably different from most other metallic alloys (Mg, Al, Cu, etc.). Detailed microstructure observations were conducted to unveil the mechanisms behind this abnormal phenomenon. Annealing for 1440 min induced not only an abnormal increase in texture intensity from 17.06 to 30.53 (which can be ascribed to preferential growth of high-texture grains with the<−12 to 10 >and<01–10 >components) but also a significant grain growth from 3.3 µm to 32.7 µm. Grain growth and dislocation annihilation resulted in the loss of strength, while the abnormal decrease in ductility during annealing was primarily due to texture enhancement and grain coarsening. The present work could provide guidance for the production and application of wrought Zn alloys in biomedical fields. • Abnormal decrease of strength and ductility simultaneously during annealing was observed for Zn-0.5Cu ECAP alloy. • Microstructure evolution of ECAP alloy under various annealing time were characterized. • Reasons resulting in the simultaneous loss of strength and ductility was expounded. [ABSTRACT FROM AUTHOR]

Deformation at a high-strain rate and low stress is of great significance for the emerging entropic alloys. However, this deformation process is generally achieved under heating or cryogenic conditions to ensure a good plasticity. Here, we demonstrate a facile route to enhance the plasticity of entropic alloys at ambient temperature. Assisted by ultrasonic vibration at a frequency of 20,000 Hz, the compression strain of the Al 80 Li 5 Mg 5 Zn 5 Cu 5 entropic alloy increases from 17% under conventional compression to 30% within 1 s, while the applied stress is less than 100 MPa, only 1/6 of the compressive strength. In contrast to conventional compression, the ultrasonic loading achieves a high-instantaneous strain rate up to 103 s−1 and high-frequency cyclic loading. This loading mode results in reflected stress waves and stress-relief effects in the deformation areas, thus causing the dislocations diffusion in face-centered-cubic (FCC) phases as well as the refinement and dispersion of intermetallic phases in the entropic alloy. These distinct microstructural evolutions synchronously suppress dislocations pile-up, and facilitate the grains rotation and sub-grains formation, which significantly decrease the deformation stresses, accommodate higher plastic strains, and eliminate deformation textures. Our studies discover a novel deformation mechanism for the entropic alloy that can offer a versatile approach of rapid structure forming. [Display omitted]. [ABSTRACT FROM AUTHOR]

The microstructure of AZ31 magnesium alloy was modified by Ca addition. AZ31-Ca alloys with refined microstructure exhibited significantly enhanced corrosion resistance in artificial seawater. AZ31–0.5Ca showed the lowest corrosion rate of 0.716 ± 0.186 mm y−1, which was about 7.4 times lower than that of AZ31 alloy (5.326 ± 0.652 mm y−1). The dominant role in the reduced corrosion rates of AZ31-Ca alloys gradually changed from the compact corrosion products film containing Al 2 O 3 and CaCO 3 to the corrosion barriers consisting of net-like (Mg, Al) 2 Ca phases as the Ca content increased from 0.1 wt% to 1.5 wt%. • The AZ31-xCa (x = 0.1, 0.5, 1.0, 1.5) Mg alloys exhibited enhanced corrosion resistance in artificial seawater. • The corrosion resistance of Ca-containing AZ31 alloys presented variations of three periods. • The dense surface film containing Al 2 O 3 and CaCO 3 was the decisive factor when the Ca content did not exceed 0.5 wt%. • The barriers effect of the net-like (Mg, Al) 2 Ca phases dominated corrosion as the Ca content reached 1.5 wt%. [ABSTRACT FROM AUTHOR]

In this study, we systematically investigated the effect of equal channel angular pressing (ECAP) on the formation of heterogeneous microstructure and mechanical properties of Zn–1Cu alloy. The obtained results showed that both low-temperature (room temperature and 150 °C) and high-temperature (200 and 300 °C) ECAP processing with eight passes facilitate the generation of triple heterogeneous microstructure, including heterogeneous distribution of CuZn 4 precipitates, η-Zn grain size, and η-Zn grain texture in the precipitates-free zones (PFZs) and precipitates zones (PZs). The major microstructural difference is that the PZs in low-temperature ECAP alloys are composed of DRX grains with weak texture, while that in high-temperature processed alloys consist of DRX grains with even stronger texture intensity than the PFZs. As both PFZs and PZs act as the soft domains, the ECAP alloy processed at low temperatures show low strength but high ductility with elongation higher than 60%. The hetero-deformation induced strengthening could be effectively activated in high-temperature processed alloys because the PZs become much stronger, which contributes to the excellent mechanical properties with high ultimate tensile strength of 231 MPa and moderate elongation of 25.9%. This work provides a unique insight into the design and preparation of Zn–Cu based alloys with tunable strength and ductility. [ABSTRACT FROM AUTHOR]

It is widely recognized that rolling Mg alloys is difficult due to their poor ductility. Conventional rolling of Mg alloys often needs to be conducted at high temperatures with multi-pass small thickness reduction, and the strong basal texture often leads to poor ductility and plate cracking. Herein, we conducted a single-pass high-reduction rolling (SPHRR) on AZ91 alloy after pre-homogenization (PH) and RD-ECAP pre-processing (PH + ECAP). Results shows that the AZ91 rolled plate processed by SPHRR (PH + ECAP + R) exhibits a good combination of high tensile strength (ultimate strength of ~420 MPa, yield strength of ~335 MPa) and high ductility (elongation-to-failure of ~19%), together with significantly reduced edge cracks. Microstructure examinations revealed that the improved mechanical property is mainly attributed to a typical bimodal grain structure featured with relatively high Schmidt factors of basal slips (SF basal). The fine-grain structure produced by the high-pass RD-ECAP pre-processing contributes to the improvement of formability, provides favourable conditions for dynamic recrystallization (DRX) in further rolling and also promotes the formation of the bimodal structure. Overall, the high-pass RD-ECAP is applicable to improve plastic formability of hard-to-deform materials like Mg alloys, and thus has a promising prospect for industrial applications. [ABSTRACT FROM AUTHOR]

Although equal channel angular pressing (ECAP) effectively improves the mechanical properties of Mg alloys, it suffers from several problems, like complexity, being time-consuming, and being feasible for small sample sizes, which limit its potential application in industrial fields. Herein, we developed a compact processing route that combined industrial-scale ECAP with partial pre-homogenization and post-aging processes (rather than the commonly used full pre-homogenization and post-aging processes) to improve the processing efficiency. Using this compact processing route, we obtained an industrial-scale AZ91 ECAP alloy with a superior combination of high strength and good ductility. A multi-heterostructure with a heterogeneous grain structure and heterogeneous precipitates characterized the microstructure of this alloy. The heterogeneous grain structure comprised coarse grains and fine grains, and the heterogeneous precipitates included precipitate-dense grains and precipitate-sparse/free grains. The optimal mechanical properties stemmed from the simultaneous effects from the heterogeneous grain structure, heterogeneous precipitates, grain refinement, fine and dense γ-phase particles, and basal plane texture component. The present result highlights the impact of the initial second phase morphology and size on the microstructure evolution during subsequent ECAP or conventional thermo-mechanical treatments, which provides a new approach to control the microstructure of Mg alloys. • ECAP combined with a partial pre-homogenization is developed for AZ91 alloy. • An industrial-scale ECAP alloy with high strength and good ductility is obtained. • A multi-heterostructure characterizes the microstructure of this alloy. • The detailed mechanism for improved ductility and strength is discussed. [ABSTRACT FROM AUTHOR]

A high strength, good ductility and cost-effective Mg alloy is highly desirable for the light-weighting application. Here, a combined processing route of hot extrusion with multi-pass rotary die equal channel angular pressing (RD-ECAP) was applied to AZ91 Mg alloy with the aim of simultaneously improving its strength and ductility. The anisotropic mechanical behavior of the ECAP alloy was investigated in comparison to the extruded alloy. The evolution of the microstructure and deformation texture was further examined as a function of the ECAP pass to construct the microstructure/texture-anisotropic properties link. The results indicate that the ECAP alloy exhibits a simultaneous improvement in both strength and ductility along three orthotropic directions compared to the as-cast alloy, and more ECAP passes continue this improvement trend. Thus, the optimal mechanical properties with the yield strength of 214.3–279.9 MPa, the ultimate tensile strength of 321.0–382.0 MPa, and the elongation of 8.2–15.5% along three tensile directions are achieved in the ECAP alloy after 12 passes RD-ECAP. This also implies a considerable anisotropy in the ECAP alloy, but it is significantly weakened compared to the extruded alloy. Moreover, it is found that the low ECAP pass (4 passes) is enough to achieve a homogenous microstructure, which is characterized by the uniform and fine equiaxed grains (~7 μm) with the fine β precipitates (~1.5 μm) along the grain boundaries. Therefore, the initial extrusion can accelerate the grain refinement and microstructure homogenization in subsequent ECAP processing. Increasing the ECAP passes over 4, there are no discernible changes in the grain and precipitate microstructures, but the texture migration is observed. The high strength of the ECAP alloys not only stems from the well-known refinement strengthening, but also for texture strengthening. The contribution of the texture strengthening is enhanced with the increase of the ECAP pass. [ABSTRACT FROM AUTHOR]

Excellent ductility and high strength were achieved in the Mg-10.6Gd-2Ag (wt. %) alloy via an industrial-scale equal channel angular pressing (ECAP). The ECAP alloy exhibits an extremely high ductility (elongation of 22.6%) as well as a high strength (ultimate tensile strength of 417.2 MPa). This ductility exceeds the known ductility limit of the existing high-strength Mg-RE wrought alloys. After peak-aging, an optimal ultimate tensile strength of 460.3 MPa is obtained accompanied by a moderate ductility (elongation of 8.9%). The excellent ductility originates from the fine and full DRXed microstructure, which involves the homogenous and fine equiaxed grains, the cobblestone-like submicron particles distributed along the α -Mg grain boundaries, and the weak and approximately random texture. The submicron particles are identified as the dynamically precipitated Ag-containing Mg 5 Gd-typed compound. After peak-aging, co-existence of the high-density basal γ " plates and the relatively low-density prismatic β ′ plates are observed in the α -Mg grain interior, and an interfacial phase is found to segregate in some α -Mg grain boundaries. The high strength is mainly ascribed to the synergistic effect of the fine grains, the high-frequency high angle boundaries, and the additional co-precipitates of the β ′ plates and the γ " plates in the aged alloy. • We developed a high-strength Mg-10.6Gd-2Ag alloy via an industrial-scale ECAP. • The ECAP alloy exhibits an extremely high ductility (EL of 22.6%). • The ECAP alloy possesses a full DRXed homogenous microstructure. • Co-existence of the γ " plates and β ′ plates are observed in peak-aged alloy. • The detailed mechanism for improved ductility and strength are discussed. [ABSTRACT FROM AUTHOR]