Addition Of Zirconium Research Articles

Investigation the structure in cast and deformed states of aluminum alloy, economically alloyed with scandium and zirconium

The structure and mechanical properties of an alloy of the aluminum-magnesium system with a scandium content of no more than 0.1% (wt.) (experimental alloy) at the stages of obtaining sheet semi-finished products have been investigated. The macro and micro structure of cast, hot, and cold rolled sheet semi-finished products has been studied by the methods of light and diffraction transmission electron microscopy, and their mechanical properties have been tested. Casting of ingots, hot, and cold rolling of the alloy was carried out in the conditions of a metallurgical enterprise. The section of the ingots was a rectangle 300 × 1460 mm in size. Preparation of ingots for rolling included milling of all surfaces and two-stage annealing at temperatures of 350 °C (first stage) and 425 °C (second stage). Rolling was carried out across the casting direction. For hot rolling, the billets were heated to 400–410 °C and carried out on a reversible hot rolling mill of grade quart with a roll barrel length of 2800 mm to a thickness of 8.2–9.2 mm. Then, the strips were rolled into rolls and annealed according to the following regime: temperature 390–400 °С, holding for 1 h, cooling with a furnace to 250–270 °С, and unloading into air. Cold rolling was carried out on a QUARTO mill of the CRM grade with a roll barrel length of 2800 mm to a thickness of 5.9–6.3 mm. Microstructural analysis was performed on a Carl Zeiss Axio Observer A1m light microscope using the AxioVision software package. The fine structure of semi-finished products was studied using Tecnai 30 G2 and JEM-2100 EX transmission electron microscopes. The chemical composition of dispersed particles of the secondary phases was determined using energy dispersive X-ray microanalysis (EDX) of thin foils in transmission using an INCA x-sight attachment. It is shown that alloying the experimental alloy with small additions of scandium, zirconium, and manganese leads to the formation of a supersaturated solid solution in the ingot. And upon annealing of the ingot and subsequent hot and cold rolling, a subgrain structure with inclusions of Al6Mn and Al3(Sc, Zr) phases of distribution density is formed in the alloy structure, explaining dispersion and structural hardening of sheet semi-finished products. It was found that the mechanical properties of cold-rolled sheets from the experimental alloy significantly exceed the properties of alloy 5083 with the same magnesium content. But without scandium and are approximately on the same level with alloy 1570 in which the scandium content in comparison with the experimental alloy is three times higher.

Zhe role of zirconia additions on the microstructure and corrosion behavior of Ni-Cr dental alloys

This study investigates the effect of zirconia addition with different percentages on Ni-Cr alloy using a powder metallurgy technique. The scanning electron microscope with energy dispersive spectroscopy is used to analyze the microstructure of Ni-Cr and Ni-Cr-x ZrO2 (where x is 3, 6, 9 wt.%) alloys. The x-ray diffraction method is used to determine the phases for Ni-Cr and Ni-Cr/ZrO2 alloys. The corrosion and ion release tests were also achieved using potentiodynamic polarization and atomic absorption spectroscopy. According to the microstructural investigation, the results found that the Ni-Cr alloy’s grain size tends to reduce with the addition of ZrO2 with obtaining the smallest grain size with 6 wt.% addition. The potentiodynamic polarization exhibited that the modified alloys are more resistant to corrosion in the saliva medium than the Ni-Cr alloy. Furthermore, the role of ZrO2 in dissolution test shows the development in the passive layer’s resistance compared to unmodified alloys with reducing the Ni release from 2.5 ppm to 0.2 ppm. It can conclude that the addition of ZrO2 has significantly improved Ni-Cr’s biocompatibility and extend the area of implementations.

The effect of Zr on dynamic recrystallization during ECAP processing of Mg-Y-RE alloys

Two magnesium alloys containing yttrium and rare-earth elements were processed by equal channel angular pressing (ECAP) to explore the effect of the small addition of zirconium on the resulting microstructures. The composition of the alloys was Mg–3.8wt%Y–2.6 wt%RE–0.45 wt%Zr (WE43) and Mg–4.1wt%Y–2.8wt%Nd (WN43), respectively. It is shown that small Zr addition facilitates the formation of small secondary phase particles. The particles become smaller, and their distribution is denser. Consequently, the grain nucleation processes are more active, grain growth is suppressed, and the final grain size is smaller. The faster nucleation rate affects the texture formation during ECAP as well. It is shown that this effect is independent of the initial microstructural condition concerning both the grain size and the presence/distribution of secondary phase particles. The positive impact of Zr was proven employing scanning and transmission electron microscopy, texture measurements by X-ray diffraction and further reflected in the improved strength of the material in terms of microhardness and compression testing. It was shown that, in this way, the microstructure and texture of Mg-RE alloys could be effectively tailored by small Zr additions.

Thermal decomposition and reaction sintering for synthesis of mullite-zirconia composite using kaolin, γ-alumina and zirconia

The refractory materials used in the wall of the furnaces for glass melting can be prepared from mullite-zirconia composite material. The composite of mullite/zirconia was synthesized from Iraqi kaolin, γ-alumina, and zirconia using thermal decomposition with reaction sintering at 1600 °C. Several batches were prepared with various ratios of kaolin, γ-alumina, and zirconia, and the composite compositions were selected from the Al2O3-SiO2-ZrO2 phase diagram. The mullite-zirconia composite was prepared with different steps beginning with milling the starting materials, semi-dry uniaxial pressing, and then reactive sintering at various temperatures (1200, 1400, and 1600 °C). The predicted phases ZrO2 and Al6Si2O13 were identified by X-ray diffraction patterns according to the phase diagram for all the batches. The lower amount of the zirconia added to mullite reduced porosity and improved the bulk density of the mullite/zirconia composite. The thermal expansion coefficient slightly increased with the addition of zirconia. It also enhanced the thermal shock resistance of the composite. Finally, the mechanical properties were improved by increasing the amount of zirconia particles in a matrix of mullite due to the phase transformation of zirconia from tetragonal to monoclinic phase.

Zirconium alloyed tungsten borides synthesized by spark plasma sintering

Tungsten borides (WBx; x = 2.5 or 4.5) with an increasing substitution of tungsten by zirconium from 0 to 24 at.% were synthesized by spark plasma sintering (SPS) for the first time. The influence of the holding time (2.5–30 min) on the densification behavior, microstructure evolution and development of the properties of W–Zr–B compounds were studied. The samples were characterized using scanning electron microscopy (SEM) for microstructure analysis, X-ray diffraction (XRD) for phase identification, Vickers micro-indentation for microhardness measurements, tribological tests to determine the coefficient of friction and specific wear rate, as well as measurements of electrical conductivity. The XRD results confirm the presence of the WB4 phase in the microstructure, despite the high sintering temperature (1800 °C) and small overstoichiometric excess of boron (4.5) addition in the sintered samples. This is caused by the high heating rate (400 °C/min), short holding time (2.5 min) and addition of zirconium. The Vickers hardness (HV) values measured at 1 N are 24.8 ± 2.0 and 26.6 ± 1.8 GPa for 24 at.% zirconium in WB2.5 and for 0 at.% zirconium in WB4.5, respectively. In addition, the hardest sample (W0.76Zr0.24B2.5) showed electrical conductivity up to 3.961·106 S/m, which is similar to WC–Co cemented carbides. The friction and wear test results reveal the formation of a boron-based film which seems to play the role of a solid lubricant.

Effect of Zr and Er Small Additives on the Phase Composition and Mechanical Properties of Al–5Si–1.3Cu–0.5Mg Alloy

The effect of small additions of erbium and zirconium on the microstructure, phase composition, kinetics of hardening during aging and softening during annealing after rolling of the Al–5Si–1.3Cu–0.5Mg alloy has been studied in this work. Erbium and zirconium form a phase of crystallization origin with aluminum, silicon, copper, and magnesium, which does not dissolve and does not change its morphology in the process of homogenization before quenching. Erbium and zirconium increase the aging effect after quenching, especially at 210°C, increase the yield stress at elevated temperatures, reduce the tendency to soften during annealing after rolling, and reduce the recrystallized grain size due to dispersoids formed during homogenization. Quenching of deformed sheets with subsequent aging leads to the achievement of slightly lower yield strength than low temperature annealing after rolling. In this case, a significantly higher ultimate strength of 344–375 MPa and ductility of 11.0–14.7% are achieved. The alloy with small additions of zirconium and erbium has higher characteristics of both strength and plasticity.

СПЛАВЫ НА ОСНОВЕ АЛЮМИНИЯ С ДОБАВКАМИ СКАНДИЯ И ЦИРКОНИЯ В АДДИТИВНОМ ПРОИЗВОДСТВЕ (обзор)

The article provides a review of scientific and technical literature in the field of development of alloys with additions of scandium and zirconium and their use for parts of additive manufacturing. The article describes the character of the influence of scandium and zirconium on the formation of a bimodal structure during synthesis. The factors influencing the formation of hot cracks in synthesized samples are given. The effect of compression on the density, size and ratio of the number of equiaxed and columnar crystallites in the structure, roughness and mechanical properties of synthesized alloys with additions of scandium and zirconium, including alloys with experimental compositions, is shown.

Change of Tensile Properties with Aging Time and Temperature in Al‐Si‐Cu‐Mg 354 Cast Alloys with/without Minor Addition of Ni and/or Zr

The principal aim of the present research work was to investigate the effects of minor additions of nickel and zirconium on the strength of cast aluminum alloy 354 at room temperature (25°C). A decrease in tensile properties of ∼10% with the addition of 0.4 wt.% nickel is attributed to a nickel‐copper reaction which interferes with the formation of Al2Cu precipitates. The platelet‐like phases (Al,Si)3(Zr,Ni,Fe) and (Al,Si)3(Zr,Ti) are the main features observed in the microstructures of the tensile samples of alloys with Zr additions. The reduction in mechanical properties is due to the increase in the percentage of intermetallic phases formed during solidification; such particles would act as stress concentrators, decreasing the alloy ductility. The main effect of Zr addition lies in a significant reduction in the alloy grain size ∼40%, rather than an increase in the mechanical properties. Quality index charts could be used in assessing the effects of the Ni and Zr additions to the base alloy, as well as evaluating the heat treatment relationships to the alloy tensile properties, in particular when the system shows multiple precipitation reactions. Due to the high liquidus temperature of the Al‐Zr binary phase diagram, addition of Zr beyond 0.2% is not recommended to avoid undissolved Zr.

ИССЛЕДОВАНИЕ ФАКТОРОВ, СПОСОБСТВУЮЩИХ НЕCАНКЦИОНИРОВАННОМУ ИНИЦИИРОВАНИЮ ЭНЕРГОНАСЫЩЕННЫХ МАТЕРИАЛОВ

The results of experimental studies on the initiation of compositions containing energy-saturated materials by high-current electron beams and electrodischarge plasma are presented. Experimental studies simulate the effects on energy-saturated materials of electromagnetic fields of natural and man-made origin. The threshold voltage of the electrical breakdown of the compositions during a high-voltage electric discharge was determined and the possibility of initiation of the compositions by high-current electron beams of nanosecond duration using a pulsed high-current electron accelerator GKVI-300 was studied. Four compositions were selected as objects of study: a composition based on potassium picrate, a composition containing ammonium perchlorate, a composition based on lead minium with zirconium and colloxylin additives, and ballistite composition SBK-3. It is shown in the work that the initiation of compositions by a high-current electron beam is potentially possible only for compositions with low ignition temperatures, ignition of compositions with high ignition temperatures is possible due to the introduction of a powdery nanoscale additive, particles of which have specific heat less than particles of an energy-saturated material, and ignition of ammonium perchlorate is possible only if the particles of the additive have lower thermal conductivity than the particles of perchlorate ammonium.

Influence of zirconium addition on microstructure, hardness and oxidation resistance of tantalum nitride thin films

Ta1-xZrxN thin films were deposited by reactive magnetron sputtering aiming to investigate the influence of zirconium addition on the microstructure, hardness and high temperature oxidation resistance of the coatings. GAXRD showed that all Ta1-xZrxN thin films maintained ZrN crystalline structure, forming a TaZrN solid solution. Zr incorporation did not alter hardness values of Ta1-xZrxN coatings, however, promoted significant improvements in the oxidation resistance when compared to pure TaN thin films.

Effect of Zirconium additions on microstructure and mechanical properties of hot rolled Al-Mg alloys

In this study, the mechanical properties and microstructure of as cast and hot rolled Al-4 Mg alloy matrix was carried out and the effect of Zirconium additions onAl-Mg alloys were also investigated. X-ray powder diffraction was performed for studying the crystalline nature of Al-4 Mg alloy and Al-4 Mg-0.2Zr alloy. Tensile specimens were prepared from hot rolled plates as per ASTM standards and tensile test were conducted at room temperature. Addition of Zr to the alloy matrix showed a reduction in grain size from 117 ± 8 µm to 73 ± 23 µm that can be attributed to formation of Al3Zr dispersoids. Results showed an increase in ultimate tensile strength from 244 MPa to 254 MPa after addition of Zr to Al-Mg alloy. This increase in strength can be attributed to grain refinement due to formation of Al3Mg2 dispersoids. Fractography results displayed loss of ductility with the formation of Al3Zr phase. The increase in strength and reduction in elongation due to Zr addition in Al-Mg alloy makes it suitable for aerospace application.

Next-generation anion exchange membrane water electrolyzers operating for commercially relevant lifetimes

Alkaline anion exchange membrane (AEM) water electrolysis has gained increasing attention due to its potential to achieve low-cost, high performance hydrogen production. However, most existing membranes are not durable in industrial settings. Here, we demonstrate good performance relative to industrial parameters using Sustainion® anion exchange membranes. Long-duration tests showed stable performance of 1 A/cm2 at 1.85 V with a degradation rate of less than 1 μV/h over 10,000 h. The projected lifetime is thus over 20 years. Daily on/off cycling performance over the course of 30 years was simulated experimentally through accelerated voltage shock tests, resulting in a performance loss of only 0.15 μV/cycle over 11,000 cycles. As shown through impact and crossover testing, an improvement in performance is achieved by the addition of zirconia to the polymer matrix and mechanically reinforcing the membrane.

Effect of solid solution state of zirconium and Al3Zr (L12) precipitates on the recrystallization behavior of Al‐0.2 wt.%Zr alloy

AbstractEffect of homogenization annealing on the existence form of zirconium in Al‐0.2wt.%Zr alloy and effect of various existence form of zirconium on the recrystallization behavior of Al‐0.2wt.%Zr cold‐rolled (total deformation is 92.8 %) sheet are studied. The results show that large numbers of nearly spherical Al3Zr (L12) nanoparticles precipitated from aluminum matrix after homogenizing at 475 °C for 24 h. Moreover, due to the precipitation of Al3Zr particles, the hardness and electrical conductivity of the as‐cast Al‐0.2wt.%Zr alloy is increased from 25.1±0.5 HV 3 and 54.0±0.2 %IACS to 28.6±0.7 HV 3 and 56.2±0.1 %IACS, respectively. Hence, zirconium exists as solid solution state in the as‐cast Al‐0.2wt.%Zr alloy and metastable Al3Zr phase in the homogenized alloy. Moreover, the recrystallization temperature of the pure aluminum without addition of zirconium is 300 °C, while the recrystallization temperature of the Al‐0.2wt.%Zr alloy without and with homogenization is about 350 °C and 400 °C, respectively. Obviously, the solid solution state of zirconium has certain effect on retarding the recrystallization of aluminum alloy, while the nanometer Al3Zr particles can inhibit the recrystallization of aluminum alloy effectively and increase the recrystallization temperature remarkably.

Effects of zirconium addition on electrochemical and mechanical properties of Mg-3Zn-1Ca-1RE alloy

Purpose The effect of zirconium, zinc, calcium and rare earth group as the alloying elements on mechanical properties and corrosion behavior of magnesium alloys was investigated in the simulated body fluid. Design/methodology/approach Pure magnesium and the alloying elements were melted and zirconium was finally added to obtain different alloys. The castings were annealed and some samples were aged heat treated. X-ray fluorescence was used for the elemental analysis and LSV was used for electrochemical corrosion evaluations. Findings Results showed that corrosion resistance decreases with increasing zirconium content. The lowest corrosion rate was obtained for the samples containing 0.3% and 0.45% of Zr from annealed and aging heat-treated samples, respectively. Yield stress enhances with increasing the zirconium content and degrades by the aging heat treatment. Originality/value These alloys were studied for the first time. Effect of casting without using protective flux and vacuum furnaces. Effect of annealing at 440°C for 2 h and artificial aging at 200°C for 16 h. Alloy’s electrochemical behavior on the body’s simulation environment has been investigated. Improvement of mechanical properties after annealing heat treatment by high zirconium percentage.

Effect of hafnium transition metal additives on the microstructure of 01570 aluminum alloy

The study addresses the effect of hafnium on microstructure, mechanical properties and stability of Al3Sc type strengthening particles in Al – Mg system 01570 alloy with scandium and zirconium additions. As part of the study, 01570 alloy-based ingots with hafnium content of 0.1% and 0.2% (here and everywhere hereinafter % weight is indicated) were cast in steel chill molds with zirconium and without zirconium addition. The obtained ingots grains size was examined using optical microscope. It was established, that 0.2% Hf addition to the previously designed 01570 alloy can reduce the average nominal grain diameter by half. A number of anneals was performed at temperatures of 400 oC and 450 oC with 1, 10, 30 minutes, 1, 4, 8, 16, 32 and 56 hours soaking times, to study the rate of supersaturated solid solution decomposition and determine the moment of strengthening dispersed particles coalescence onset. Annealed samples were measured for microhardness, electrical resistance and examined using scanning electron microscopy. It was demonstrated, that samples with hafnium do not lose strengthening phase stability at traditional treatment temperature of 400 oC with considerable soaking time (up to 56 h), at 450 oC decrease in microhardness is observed only after 4 hours of soaking. The samples were pressure-formed, i.e., hot and cold rolled, to determine recrystallization onset, it was established, that even at 500 oC and short soaking period (up to 30 minutes) rolled samples with hafnium still have some not recrystallized microstructure, while the samples without hafnium have visible equiaxed recrystallized grains. Using transmission electron microscope, it was possible to establish that the dispersed particles obtained in the alloy with 0.2% Hf retain a size of about 9 nm after the treatment cycle, and the average distance between them is 62 nm.The study was supported by a grant from the Russian Science Foundation, project 18-79-10099.

Understanding first cycle hydrogenation properties of Ti–Fe–Zr ternary alloys

Zirconium has been used as an alloying element to mitigate the difficulty in the initial hydrogenation of pristine TiFe, a room-temperature hydrogen storage material. The addition of zirconium induces the formation of AB2-type ternary phases such as τ1 and τ3. In this study, these ternary phases were produced individually and their activation kinetics and hydrogen storage properties were assessed. Ultimately, both τ1 and τ3 can be activated at room temperature under hydrogen at a pressure of 3 MPa. The result validates the presumption that Zr-added TiFe is easily activated with the help of the Ti–Fe–Zr ternary phases. In addition, they can store 1.8–1.9 wt% of hydrogen, which proves their own use as a hydrogen storage material. The easy activation may be caused by the compositional inhomogeneity of mixed metal oxide at the alloy surface, as revealed by depth-profiling X-ray photoelectron spectroscopy; this provides new reaction pathways for hydrogenation.

Pore evolution and slag resistance of corundum castables with nano zirconia addition

The effect of nano-zirconia addition on the microstructure and properties of corundum castables was studied using corundum, kyanite, alumina powder, gel powder, and nano-ZrO2 as raw materials. The results showed that adding 1.2(wt)% nano-ZrO2 could reduce the median pore diameter of the castables from 480 to 200 nm at 110 °C. After the castables were heated at 1100 °C, the cold modulus of rupture increased by 29.95%, to 24.71 MPa, and the cold compressive strength increased by 50.32%, to 116.37 MPa. The hot modulus of rupture increased by 114.95%, to 3.59 MPa after being treatment at 1500 °C, the high surface energy of nano-ZrO2 can increase the interface energy and bonding strength between adjacent particles.

Effect of Zr Microalloying on the Microstructures and Strengthening Mechanism of As-Cast Al-Fe-Zr Alloys.

The microstructure and mechanical properties of Al-0.35Fe alloys with a series of different zirconium (Zr) additions from 0.1 to 0.4% are investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and tensile testing. The as-cast structure of the alloys varies with the Zr content. When the content of Zr is 0.1%, Zr dissolves into the aluminum (Al) matrix completely and iron (Fe) concentrates along the boundary in a network of eutectic Al3Fe. With the increase in Zr content to 0.2% and above, nanoscale Al3Zr particles appear in the alloy. With the Zr content increasing from 0.1 to 0.4%, the grain size of the Al matrix decreases from 73 to 23 μm. The morphology of the eutectic Al3Fe phase changes from short rod-like to an agglomerated structure consisting of finer and shorter rod-like shapes. The tensile and yield strengths increase while the total elongation decreases with increasing Zr content. The strengthening mechanism of the alloy can be attributed to the combination of fine-grain, solution and second-phase strengthening.

Effect of the addition of zirconium on the electrical, optical, and mechanical properties and microstructure of ITO thin films

Indium Tin Oxide (ITO) thin films are doped with zirconium (Zr) by varying the direct current (DC) power sources to investigate the effects of Zr doping on surface morphology, microstructure, and mechanical, electrical, and optical properties. The ITO:Zr specimens possess more grains with the (400) orientation when the DC power is elevated. Crystallinity and surface roughness are highly dependent on grain size. The product value of crystallinity and grain size is observed to be positively correlated to the surface roughness. Reduced modulus and hardness of specimen are lowered by increasing the DC power, and these two parameters are also positively correlated to the product of crystallinity and grain size. In this study, the choice of 35 W as the power can bring in the highest transmittance (>81%) in the wavelength region of 380–2600 nm and the lowest resistivity of all specimens. Increasing the power to be higher than 35 W will produce more excessive carriers to reduce the carrier concentration and mobility, thus elevating the resistivity. A significant rise in the infrared transmittance (800–2600 nm) compared to the undoped ITO thin film is achieved by doping the Zr into ITO with a DC power of 35 W.

The fluidity of A357 alloy with scandium (Sc) and zirconium (Zr) addition

The effect of Sc and Zr on the fluidity of A357 alloy was investigated using spiral fluidity resin sand molds. The results showed that the order of the fluidity was A357+Zr > A357+Sc > A357 > A357+Zr+Sc. The TDCP and the solidification temperature range were also discussed. With Sc and Zr addition, the TDCP and the solidification temperature range of the alloy were changed, which led to the changes of the fluidity. The order of TDCP was A357+Zr < A357+Sc < A357 < A357+Zr+Sc and the order of the solidification temperature range was A357+Zr < A357+Sc < A357 < A357+Zr +Sc. What’s more, △T2 (△T2=TP-TDCP, TP was pouring temperature) and △T1 (△T1=TN-TDCP, TN was α-Al nucleation temperature) were compared, and △T2 was better suited for fluidity investigation than △T1.