Microstructure and Mechanical Properties of NiTi Alloy Prepared by Double-Wire + Arc Additive Manufacturing Plus In Situ Heat Treatment.

In this study, NiTi shape memory alloy was prepared by double-wire + arc additive manufacturing plus in situ heat treatment using TA1 and ER-Ni welding wires as the raw materials. The results show that the microstructural evolution from the bottom to top is NiTi2 + NiTi → NiTi + Ni3Ti + Ni4Ti3 → NiTi + Ni4Ti3 + Ni3Ti2 + Ni3Ti + α-Ti. Complex thermal cycles led to the precipitation of Ni3Ti, which improves the hardness of the matrix (B2), and the average hardness value of the top region reaches 550.7 HV0.2. The fracture stress is 2075 ± 138.4 MPa and the fracture strain is 11.2 ± 1.27%. The sample shows 7.02% residual strain and 5.87% reversible strain after 15 cycles, and the stress hysteresis decreases with an increase in cyclic strain.

Mitigating Adverse Effects of Cu-containing Intrauterine Devices Using A Highly Biocompatible Cu-5Fe alloy.

Copper-containing intrauterine devices (Cu-IUD) are adopted by worldwide women for contraception with the advantages of long-term effectiveness, reversibility and affordability. However, adverse effects occur in the initial implantation stage of Cu-IUD in uterine because of the burst release of Cu2+. To minimize the burst release, in this study, we designed a series of Cu-Fe alloys with 0.5 wt%, 1 wt% and 5 wt% Fe and also further produced ultrafine grained (UFG) structure for these alloys via equal-channel angular pressing. The microstructures and properties of the coarse grained (CG) Cu, CG Cu-Fe alloys and UFG Cu-Fe alloys were systematically investigated, including grain structure and phase compositions, metallic ions release behavior, electrochemical corrosion performance, and in vitro cytotoxicity. With careful comparison and selection, we chose the CG Cu-5Fe and UFG Cu-5Fe for in vivo tests using rat model, including tissue biocompatibility, in vivo corrosion behavior, and contraceptive effectiveness. Moreover, the corrosion mechanism of the Cu-5Fe alloy and its improved biocompatibility was discussed. Both CG and UFG Cu-5Fe alloys exhibited dramatic suppression of Cu2+ release in simulated uterine fluid for the long-term immersion process. The in vivo tissue compatibility was significantly improved with both CG and UFG Cu-5Fe alloys implanted in the rats' uterine while the high contraceptive efficacy was well maintained. Due to the superior biocompatibility, the CG and UFG Cu-5Fe alloys can be the promising candidate material for Cu-IUD. STATEMENT OF SIGNIFICANCE: A highly biocompatible Cu-Fe alloy was designed and fabricated for Cu-containing intrauterine devices (Cu-IUD). With 5wt% Fe, the burst release of Cu2+ is inhibited due to the formed galvanic cell of Cu and Fe, resulting in earlier release of Fe3+. As Fe is the most abundant essential trace element of human body, it can mitigate the toxic effects of Cu2+, thus significantly improving both in vitro cell compatibility and in vivo tissue compatibility. More importantly, the Cu-5Fe alloy exhibits 100% contraceptive efficiency as the CG Cu, but with greatly reduced adverse effects to the uterus tissues. An advanced Cu-IUD can be developed using Cu-Fe alloys.

Integrating Active Learning and DFT for Fast-Tracking Single-Atom Alloy Catalysts in CO2-to-Fuel Conversion.

Electrocatalytic carbon dioxide reduction (CO2RR) technology enables the conversion of excessive CO2 into high-value fuels and chemicals, thereby mitigating atmospheric CO2 concentrations and addressing energy scarcity. Single-atom alloys (SAAs) possess the potential to enhance the CO2RR performance by full utilization of atoms and breaking linear scaling relationships. However, quickly screening high-performance metal portfolios of SAAs remains a formidable challenge. In this study, we proposed an active learning (AL) framework to screen high-performance catalysts for CO2RR to yield fuels such as CH4 and CH3OH. After four rounds of AL iterations, the ML model attained optimal prediction performance with the test set R2 of approximately 0.94 and successful prediction was achieved for the binding free energy of *CHO, *COH, *CO, and *H on 380 catalyst surfaces with an accuracy within 0.20 eV. Subsequent analysis of the SAA catalysts' activity, selectivity, and stability led to the discovery of eight previously unexplored SAA catalysts for CO2RR. Notably, the surface activity of Ti@Cu(100), Au@Pt(100), and Ag@Pt(100) shines prominently. Utilizing DFT calculations, we elucidated the complete reaction pathway of the CO2RR on the surfaces of these catalysts, confirming their high catalytic activity with limiting potentials of -0.11, -0.34, and -0.46 eV, respectively, which are significantly lower than those of pure Cu catalysts. The results showcase the exceptional predictive prowess of AL, providing a valuable reference for the design of CO2RR catalysts.

A(CoFe)(S2)2/CoFe heterostructure constructed in S, N co-doped carbon nanotubes as an efficient oxygen electrocatalyst for zinc-air battery.

Transition metal alloys can exhibit synergistic intermetallic effects to obtain high activities for oxygen reduction/evolution reactions (ORR/OER). However, due to the insufficient stability of active sites in alkaline electrolytes, conventional alloy catalysts still do not meet practical needs. Herein, by using polypyrrole tubes and cobalt-iron (CoFe) Prussian blue analogs as precursors, CoFe sulfides is in-situ formed on CoFe alloys to construct (CoFe)(S2)2/CoFe heterostructure in sulfur (S) and nitrogen (N) co-doped carbon nanotubes (CoFe@NCNTs-nS) via a low-temperature sulfidation strategy. The as-marked CoFe@NCNTs-12.5S exhibits a comparable ORR activity (half-wave potential of 0.901 V) to Pt/C (0.903 V) and a superior OER activity (overpotential of 272 mV at 10 mA cm-2) to RuO2 (299 mV). CoFe@NCNTs-12.5S also exhibits ultralow charge transfer resistances (ORR-6.36 Ω and OER-0.21 Ω) and an excellent potential difference of 0.617 V. The sulfidation-induced (CoFe)(S2)2/CoFe heterojunctions can accelerate interfacial charge transfer process. Tubular structure not only disperses the (CoFe)(S2)2/CoFe heterostructure, but also reduces the corrosion of active-sites to enhance catalysis stability. Zinc-air battery with CoFe@NCNTs-12.5S achieves a high specific capacity (718.1 mAh g-1), maintaining a voltage gap of 0.957 V after 400 h. This work reveals the potential of interface engineering for boosting ORR/OER activities of alloys via in-situ heterogenization.

Application of Reversible Four-Dimensional Printing of Shape Memory Alloys and Shape Memory Polymers in Structural Engineering: A State-of-the-Art Review.

The rapid development and advancements in field of shape memory alloys (SMAA) has tremendously increased the progress in four-dimensional (4D) printing. The conventional 4D printing will require skilled manpower but utilization of reversibility aspect achieved using self adjusting external stimuli will eliminate the necessity of sophisticated devices and human intervention in 4D printing. The components created using reversible 4D printing can be reused after each recovery cycle that suits the current industry requirements. This review is divided into three sections: The first section starts with a detailed illustration of different mechanisms associated with SMAA and shape memory polymers SMPP along with an illustration of realistic 3D-printed SMAA and SMPP. The second section of this paper deals with the different methods of manufacture with the advantages and disadvantages of different types of SMAA. The third section deals with the mechanisms associated with SMPP, namely (1) Thermo-responsive mechanism, (2) Chemo-responsive mechanism, and (3) Photo-responsive mechanism along with a detailed insight into the aspect of repeatability and reversibility. The fourth section presents an exhaustive review of the application of SMAA and SMPP in civil engineering. The last section of this work throws light on the challenges faced in 4D reversible printing of SMAA and SMPP along with the potential solutions and presents directions for future research.

Highly plastic Zn-0.3Ca alloy for guided bone regeneration membrane: Breaking the trade-off between antibacterial ability and biocompatibility.

A common problem for Zn alloys is the trade-off between antibacterial ability and biocompatibility. This paper proposes a strategy to solve this problem by increasing release ratio of Ca2+ ions, which is realized by significant refinement of CaZn13 particles through bottom circulating water-cooled casting (BCWC) and rolling. Compared with conventionally fabricated Zn-0.3Ca alloy, the BCWC-rolled alloy shows higher antibacterial abilities against E. coli and S. aureus, meanwhile much less toxicity to MC3T3-E1 cells. Additionally, plasticity, degradation uniformity, and ability to induce osteogenic differentiation in vitro of the alloy are improved. The elongation up to 49 %, which is the highest among Zn alloys with Ca, and is achieved since the sizes of CaZn13 particles and Zn grains are small and close. As a result, the long-standing problem of low formability of Zn alloys containing Ca has also been solved due to the elimination of large CaZn13 particles. The BCWC-rolled alloy is a promising candidate of making GBR membrane.

Spontaneous Orientation Polarization of Anisotropic Equivalent Dipoles Harnessed by Entropy Engineering for Ultra-Thin Electromagnetic Wave Absorber.

The synthesis of carbon supporter/nanoscale high-entropy alloys (HEAs) electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes. Electron migration modes within HEAs as manipulated by the electronegativity, valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles. Herein, enlightened by skin-like effect, a reformative carbothermal shock method using carbonized cellulose paper (CCP) as carbon supporter is used to preserve the oxygen-containing functional groups (O·) of carbonized cellulose fibers (CCF). Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·. Meanwhile, the electron migration mode of switchable electron-rich sites promotes the orientation polarization of anisotropic equivalent dipoles. By virtue of the reinforcement strategy, CCP/HEAs composite prepared by 35% molar ratio of Mn element (CCP/HEAs-Mn2.15) achieves efficient electromagnetic wave (EMW) absorption of - 51.35 dB at an ultra-thin thickness of 1.03 mm. The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations, which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices (e.g., ultra-wideband bandpass filter).

Enhanced Magnetocaloric Properties of the (MnNi)0.6Si0.62(FeCo)0.4Ge0.38 High-Entropy Alloy Obtained by Co Substitution.

In order to improve the magnetocaloric properties of MnNiSi-based alloys, a new type of high-entropy magnetocaloric alloy was constructed. In this work, Mn0.6Ni1-xSi0.62Fe0.4CoxGe0.38 (x = 0.4, 0.45, and 0.5) are found to exhibit magnetostructural first-order phase transitions from high-temperature Ni2In-type phases to low-temperature TiNiSi-type phases so that the alloys can achieve giant magnetocaloric effects. We investigate why chexagonal/ahexagonal (chexa/ahexa) gradually increases upon Co substitution, while phase transition temperature (Ttr) and isothermal magnetic entropy change (ΔSM) tend to gradually decrease. In particular, the x = 0.4 alloy with remarkable magnetocaloric properties is obtained by tuning Co/Ni, which shows a giant entropy change of 48.5 J∙kg-1K-1 at 309 K for 5 T and an adiabatic temperature change (ΔTad) of 8.6 K at 306.5 K. Moreover, the x = 0.55 HEA shows great hardness and compressive strength with values of 552 HV2 and 267 MPa, respectively, indicating that the mechanical properties undergo an effective enhancement. The large ΔSM and ΔTad may enable the MnNiSi-based HEAs to become a potential commercialized magnetocaloric material.

Investigation of Mechanical and Corrosion Properties of New Mg-Zn-Ga Amorphous Alloys for Biomedical Applications.

Magnesium alloys are considered as promising materials for use as biodegradable implants due to their biocompatibility and similarity to human bone properties. However, their high corrosion rate in bodily fluids limits their use. To address this issue, amorphization can be used to inhibit microgalvanic corrosion and increase corrosion resistance. The Mg-Zn-Ga metallic glass system was investigated in this study, which shows potential for improving the corrosion resistance of magnesium alloys for biodegradable implants. According to clinical tests, it has been demonstrated that Ga ions are effective in the regeneration of bone tissue. The microstructure, phase composition, and phase transition temperatures of sixteen Mg-Zn-Ga alloys were analyzed. In addition, a liquidus projection of the Mg-Zn-Ga system was constructed and validated through the thermodynamic calculations based on the CALPHAD-type database. Furthermore, amorphous ribbons were prepared by rapid solidification of the melt for prospective alloys. XRD and DSC analysis indicate that the alloys with the most potential possess an amorphous structure. The ribbons exhibit an ultimate tensile strength of up to 524 MPa and a low corrosion rate of 0.1-0.3 mm/year in Hanks' solution. Therefore, it appears that Mg-Zn-Ga metallic glass alloys could be suitable for biodegradable applications.

Study on the Synergistic Effects of Cu and Sr on Biodegradable Zn Alloys.

Bone defect repair and postoperative infections are among the most challenging issues faced by orthopedic surgeons. Thus, the antibacterial agent Cu and the osteogenic promoter Sr have been widely incorporated into biodegradable alloys separately. However, to the best of our knowledge, the synergistic effects of Cu and Sr on zinc alloys have not been investigated. Therefore, we have developed a series of novel Zn-4Cu-xSr (x = 0.05, 0.1, and 0.3 wt %) alloys. Our results showed that the addition of Cu and Sr significantly increased the strength of pure zinc while maintaining a certain level of ductility. Plastic deformation further enhanced the strength and ductility of the alloys. The tensile strength of HR Zn-4Cu-xSr alloys remains between 233.34 ± 1.31 MPa and 235.81 ± 3.0 MPa, with elongation values ranging from 45.7 ± 1.56% to 49.6 ± 6.22%. The HE Zn-4Cu-0.05Sr alloy exhibits a high elongation of 95.05 ± 11.1%. Furthermore, the HE Zn-4Cu-0.1Sr alloy demonstrates the best overall mechanical performance with ultimate tensile strength (σuts), yield strength (σys), and elongation (ε) values of 252.73 ± 0.12 MPa, 181.0 ± 0.79 MPa, and 42.8 ± 1.13%, respectively. The corrosion rate of HE Zn-4Cu-xSr alloys increases with an increase in Sr content. All samples exhibit satisfactory cytocompatibility with the cells displaying a healthy spindle-like morphology. In vitro antibacterial tests show that the HE Zn-4Cu-xSr alloys exhibit significant antibacterial effects against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), with the antibacterial properties strengthening as the Sr content increases. Therefore, this study demonstrates the tremendous potential application of Zn-4Cu-xSr alloys in biodegradable zinc alloys for bone fracture fixation and repair.

Comparative corrosion behavior of three titanium alloy base materials and their welds in a simulated chimney environment.

This study investigates the corrosion behavior of titanium alloys (TA2, TC4, TB6) in a 3 % sulfuric acid flue gas environment using electrochemical tests and microscopic analyses (SEM/EDS, XRD, metallographic microscopy). Results show that TA2 base metal has lower corrosion resistance compared to its weld metal, while TC4 and TB6 exhibit opposite trends. Specifically, TC4 and TB6 base metals have lower corrosion current densities (0.9 and 0.5 µA/cm2) and higher corrosion potentials then their weld metals (1.93 and 2 µA/cm2). In contrast, TA2 base metal showed higher corrosion current density (2 µA/cm2) than its weld metal (0.35 µA/cm2) and HAZ metal (0.16 µA/cm2). Microscopic analyses reveal ß phase transitions in TC4 and TB6 weld areas, leading to larger grain sizes and reduced corrosion resistance. Conversely, TA2 retains finer grains post-welding, enhancing its corrosion resistance. These insights clarify weld corrosion effects and provide valuable guidance for industrial applications of titanium alloys, particularly in designing and maintaining titanium alloy chimneys.

Biomimetic hydrogel coatings for improving the corrosion resistance, hemocompatibility, and endothelial cell growth of the magnesium alloy.

The fast biodegradation and poor biocompatibility of Mg alloys in physiological environments are still the main problems restricting their application in cardiovascular stents. In this study, the hydrogel coatings (SBMA-AAM) with different proportions of methacryloyl ethyl sulfobetaine (SBMA) and acrylamide (AAM) were built on the surface of AZ31B magnesium alloy through ultraviolet (UV) polymerization. The corrosion degradation behavior, hemocompatibility, and endothelial cell (EC) growth performance of the samples were studied in detail. The findings revealed that the uniform and dense SBMA-AAM coatings could significantly enhance the corrosion resistance. In addition, the hydrogel coatings showed excellent hydrophilicity, which increased the albumin adsorption while inhibiting the fibrinogen adsorption, and thus reduced the platelet adhesion and activation and hemolysis rate, accordingly significantly enhancing their anticoagulant performance. Furthermore, SBMA-AAM hydrogel coating promoted the EC adhesion and proliferation and the vascular endothelial growth factor (VEGF) and nitric oxide (NO) secretion of ECs, which is conducive to promoting endothelialization. When the concentration ratio of SBMA and AAM was 1: 2, the modified magnesium alloy showed the best corrosion resistance and biocompatibility. Therefore, the SBMA-AAM hydrogel coating could effectively regulate the corrosion degradation performance and biocompatibility of Mg alloys, laying a foundation for the application of Mg alloys in cardiovascular stents.

Modifying the Reactivity of Single Pd Sites in a Trimetallic Sn-Pd-Ag Surface Alloy: Tuning CO Binding Strength.

Improving control over active-site reactivity is a grand challenge in catalysis. Single-atom alloys (SAAs) consisting of a reactive component doped as single atoms into a more inert host metal feature localized and well-defined active sites, but fine tuning their properties is challenging. Here, a framework is developed for tuning single-atom site reactivity by alloying in an additional inert metal, which this work terms an alloy-host SAA. Specifically, this work creates about 5% Pd single-atom sites in a Pd33Ag67(111) single crystal surface, and then identifies Sn based on computational screening as a suitable third metal to introduce. Subsequent experimental studies show that introducing Sn indeed modifies the electronic structure and chemical reactivity (measured by CO desorption energies) of the Pd sites. The modifications to both the electronic structure and the CO adsorption energies are in close agreement with the calculations. These results indicate that the use of an alloy host environment to modify the reactivity of single-atom sites can allow fine-tuning of catalytic performance and boost resistance against strong-binding adsorbates such as CO.

Multi-modal investigation of the bone micro- and ultrastructure, and elemental distribution in the presence of Mg-xGd screws at mid-term healing stages.

Magnesium (Mg) - based alloys are becoming attractive materials for medical applications as temporary bone implants for support of fracture healing, e.g. as a suture anchor. Due to their mechanical properties and biocompatibility, they may replace titanium or stainless-steel implants, commonly used in orthopedic field. Nevertheless, patient safety has to be assured by finding a long-term balance between metal degradation, osseointegration, bone ultrastructure adaptation and element distribution in organs. In order to determine the implant behavior and its influence on bone and tissues, we investigated two Mg alloys with gadolinium contents of 5 and 10 wt percent in comparison to permanent materials titanium and polyether ether ketone. The implants were present in rat tibia for 10, 20 and 32 weeks before sacrifice of the animal. Synchrotron radiation-based micro computed tomography enables the distinction of features like residual metal, degradation layer and bone structure. Additionally, X-ray diffraction and X-ray fluorescence yield information on parameters describing the bone ultrastructure and elemental composition at the bone-to-implant interface. Finally, with element specific mass spectrometry, the elements and their accumulation in the main organs and tissues are traced. The results show that Mg-xGd implants degrade in vivo under the formation of a stable degradation layer with bone remodeling similar to that of Ti after 10 weeks. No accumulation of Mg and Gd was observed in selected organs, except for the interfacial bone after 8 months of healing. Thus, we confirm that Mg-5Gd and Mg-10Gd are suitable material choices for bone implants.

Preparation of electroless deposition of NiTiZr(P) quaternary alloy and their properties.

The exceptional super elasticity and corrosion-resistance of Ni-Ti alloys have attracted a lot of attention and interest lately for a wide range of applications, and complex alloy components could be prepared effectively by different preparation techniques. Ni(P), Ni-Ti(P), Ni-Zr(P), and Ni-Ti -Zr(P) binary, ternary, and quaternary alloys were coated on mild steel by electroless deposition which is a method of plating metallic films on a substrate by the reduction of metallic complex ions in solution with the aid of reducing agent from an alkaline bath. The ternary Ni-Ti-Zr(P) alloy is considered to be one of the most promising high-temperature SMAs. SEM, XRD and EDS were used to examine the morphology, phase composition and elemental composition which demonstrate the microstructure of the deposits. The mechanical characteristics of the samples were examined through scratch test and micro hardness analysis and the value increased from 261 HV200 to 405 HV200 and that the coefficient of friction raised significantly from 0.23 to 3.5 owing to the presences of added elements in Ni(P) matrix. Polarization analysis and EIS were tested to evaluate the corrosion properties of coated samples in a non-deaerated 3.5 %wt. (NaCl) solution. The outcomes indicate that as the amount of Ti-Zr elements in the bath raised, the corrosion potential became more positive and the corrosion current density decreased to 14.903 µA/cm2. Furthermore, Ni-Ti-Zr(P) alloy coating strengthens corrosion resistance in comparison to Ni(P).

FeCrNi medium entropy alloys as potential shielding materials for nuclear applications.

Metallic alloys of different compositions are basic structures for building different types of nuclear reactors. This study evaluates the nuclear properties for three medium entropy alloys against incident neutrons and gamma radiation. The alloys had different chemical compositions prepared by powder technology and were compared with two stainless steel alloys for use in constructing different parts of nuclear power plant units. The shielding parameters were calculated: linear attenuation coefficient, half-value layer, tenth-value layer, mean free path, effective atomic number (Zeff), effective electronic number, and neutron removal cross-section. The Zeff of all investigated alloys had a range of 25.46-25.93.Sample 1 medium entropy alloy had the lowest neutron absorption feature and the greatest density (7.890 ± 0.323 g/cm3) and Sample 3 medium entropy alloy had the largest neutron absorption feature. The study indicates that medium entropy alloys have potential for enhancing efficiency and safety of nuclear reactors.

Properties of biodegradable polymer coatings with hydroxyapatite on a titanium alloy substrate.

Purpose: Titanium alloys are among the most widely used materials in medicine, especially in orthopedics. However, their use requires the application of an appropriate surface modification method to improve their properties. Such methods include anodic oxidation and the application of polymer coatings, which limit the release of alloying element ions. In addition, biodegradable polymer coatings can serve as a carrier for drugs and other substances. The paper presents the results of research on the physical properties of biodegradable polymer coatings containing nanoparticle hydroxyapatite on a titanium alloy substrate. Methods: A PLGA coating was used in the tests. The coatings on the substrate of the anodized Ti6Al7Nb alloy were applied by ultrasonic spray coating. The tests were carried out for coatings with various hydroxyapatite content (5, 10, 15, 20%) and thickness resulting from the number of layers applied (5, 10, 15 layers). The scope of the research included microscopic observations using scanning electron microscopy, topography tests with optical profilometry, structural studies using X-ray diffraction, as well as wettability and adhesion tests. Results: The results shows that with the use of ultrasonic spray coating system is possible to obtain the continuous coatings containing hydroxyapaptite. Conclusions: The properties of the coating can be controlled by changing the percentage of hydroxyapatite and the number of layers of which the coating is composed.

Light-Driven Reverse Water Gas Shift Reaction with 1000-H Stability on High-Entropy Alloy Catalysts.

Highly stable and active catalysts are of significant importance and a longstanding challenge for a number of industrial chemical transformations. Here, motivated by the principle of the high entropy-stabilized structure, high-entropy alloy-loaded porous TiO2 as an efficient and sintering-resistant catalyst for the light-driven reverse water gas‒shift reaction without external heating is synthesized. The optimized CoNiCuPdRu/TiO2 catalyst exhibits a long-term stability of 1000 h (1.23 mol gmetal -1 h-1 CO production rate, >99% high selectivity). In situ characterizations confirm that the slow diffusion effect of high-entropy alloys endows the catalyst with excellent structural stability. The CO adsorption measurements and theoretical calculations consolidate that the hydrogen surface coverage weakens CO adsorption on the catalyst surface. Two major problems of catalyst deactivation - sintering and poisoning, are handled in one case, which synergistically enable unparalleled stability. This work provides new guidance for the rational design of ultradurable harsh-condition operation catalysts for industrial catalysis.

Development of Flexible and Partly Water-Soluble Binder Systems for Metal Fused Filament Fabrication (MF3) of Ti-6Al-4V Parts.

Metal Fused Filament Fabrication provides a simple and cost-efficient way to produce dense metal parts with a homogenous microstructure. However, current limitations include the use of hazardous and expensive organic solvents during debinding for flexible filaments the stiffness of filaments made from partly water-soluble binder systems. In this study, the influence of various additives on different partly water-soluble binder systems, with regard to the flexibility and properties of the final parts, was investigated. Furthermore, a method using dynamic mechanical analysis to quantify the flexibility of filaments was introduced and successfully applied. For the first time, it was possible to produce flexible, partly water-soluble filaments with 60 vol.% solid content, which allowed the 3D printing of complex small and large parts with a high level of detail. After sintering, density values of up to 98.9% of theoretical density were achieved, which is significantly higher than those obtained with existing binder systems.

Structure and Corrosion Behavior of Multiphase Intermetallic ZrCu-Based Alloys.

Zirconium-based alloys are highly regarded by the research community for their exceptional corrosion resistance, thermal stability, and mechanical properties. In our work, we investigated two newly developed alloys, Zr42.42Cu41.18Al9.35Ag7.05 and Zr46.81Cu35.44Al10.09Ag7.66, in the form of ingots and ribbons. In the course of our investigation, we conducted a comprehensive structural and thermal analysis. In addition, an examination of the corrosion activity encompassing electrochemical studies and an analysis of the corrosion mechanisms was carried out. To further evaluate the performance of the materials, tests of their mechanical properties were performed, including microhardness and resistance to abrasive wear. Structural analysis showed that both alloys studied had a multiphase, crystalline structure with intermetallic phases. The samples in the form of ribbons showed improved corrosion resistance compared to that of the ingots. The ingot containing a higher content of copper Zr42.42Cu41.18Al9.35Ag7.05 was characterized by better corrosion resistance, while showing lower average hardness and a higher degree of abrasive wear based on SEM observations after pin-on-disc tests.