Effect Of Zirconium Addition Research Articles

Effect of zirconium addition on microstructural characteristics and nano-mechanical properties of P9 steel

Micro-alloying in steels has significant effects on microstructure and its properties. The main objective of the work is to understand the influence of zirconium (Zr) addition to P9 ferritic/martensitic (F/M) steel on phase stability, microstructure, and nanomechanical properties. The alloy compositions in this study were designed using thermodynamic calculations, based on which steels with Zr concentration in the range of 0.05–2 wt.% were synthesized using vacuum arc melting. The cast alloy was subjected to thermo-mechanical treatments followed by austenitization and tempering treatments. Zr concentration of the steel was found to influence the nature of secondary phases formed, which were quantified through detailed synchrotron X-ray diffraction (XRD) analysis and also characterised extensively using electron microscopy techniques. Detailed structural analysis of the Fe23Zr6 phase using aberration corrected transmission electron microscopy is reported for the first time. The nano-mechanical properties of the heat-treated steels were evaluated using instrumented indentation tests at room temperature with a sphero-conical indenter. A systematic variation in hardness and yield strength with Zr content of P9 steel was observed, which is correlated to the microstructural changes. The P9 F/M steel with optimum concentration of Zr, with better mechanical properties is proposed through this structure-property correlation study.

Enhanced elevated-temperature mechanical properties of hot-rolled Al–Cu alloys: effect of zirconium addition and homogenization

Enhanced elevated-temperature mechanical properties of hot-rolled Al–Cu alloys: effect of zirconium addition and homogenization

(Digital Presentation) Effect of Zirconium Addition on the Corrosion Behavior of Binary Magnesium-Zirconium Alloys

Magnesium (Mg) has the characteristics of low density and high specific strength, but its poor corrosion resistance is a fatal disadvantage. Therefore, various alloying elements are often added to Mg alloys to improve their properties. Among them, zirconium (Zr) is commonly added as a grain refiner for Mg alloys. However, in most cases, Zr was added as a secondary additive, by which the effect on the corrosion properties would be shadowed by other alloying elements. Therefore, this research aims to elucidate the effect of Zr addition on magnesium corrosion with two binary Mg-Zr alloys with different Zr concentrations (0.037wt% and 0.208wt%).In this study, scanning electron microscope (SEM) with X-ray energy dispersive spectroscopy (EDS) was used to study the Zr distribution and compositional difference in the alloys. Scanning Kelvin probe force microscope (SKPFM) was used to reveal the Volta potential difference between the Zr particles and the Mg matrix. In situ optical microscopic (OM) observation combined with open circuit potential (OCP) monitor was used to record the alloy corrosion morphology evolution. And through electrochemical impedance spectroscopy (EIS) analysis, the difference in the alloy corrosion properties was investigated. Hydrogen evolution tests were used to quantify the corrosion rates.Through SEM/EDS analysis, the size, distribution, and Fe content of the zirconium particles in the alloy are the most important differences between the two samples. For the sample with 0.208wt%Zr, the Zr particles are larger and contain more Fe. From SKPFM analysis, we also found that the Volta potential difference between the Zr particles and the Mg matrix is larger for the sample with higher Zr addition. Hydrogen evolution tests show that the corrosion rate of the 0.208wt%Zr sample is about 5 times compared to the 0.037wt%Zr sample, which is consistent with the EIS analysis results. The driving force of corrosion mainly comes from the microgalvanic effect provided by the Zr particles. The relationship between the Zr particles and localized corrosion behavior will also be discussed. Figure 1

Effects of zirconium addition on the material properties and microstructure of ODS-Cu alloys

An oxide dispersion strengthened copper (ODS-Cu) alloy with Zr addition was fabricated by high-energy water-cooled mechanical alloying and spark plasma sintering (SPS). The effects of Zr addition on the material properties and microstructure of ODS-Cu alloys were investigated by comparing with the results of the Cu-1Y2O3 (wt%) ODS alloy. The addition of 0.81 Zr (wt%) to the Cu-1Y2O3 (wt%) alloy was confirmed to increase the Vickers hardness of the ODS-Cu alloy by a factor of 1.5, resulting in an unprecedented value of 243 HV. The excellent strength comes mainly from the strengthening effect caused by the refinement of the dispersed oxide particles. Fine and dense FCC-structured complex Y2Zr2O7 oxide particles were found to be uniformly distributed within the alloy, which are in good coherency with the Cu matrix, allowing the particle size to be less than half of that in Cu-1Y2O3 (wt%) ODS alloy at 7.6 nm. Although a slight decrease in the thermal diffusivity of the ODS-Cu alloy with Zr was observed, which can be attributed to the solid solution effect of the residual Fe in the matrix, this study proposes a suitable thermal aging treatment to restore the thermal diffusivity by precipitating the solute Fe.

Effects of zirconium addition on microstructures and thermal conductivities of carbon/copper composites

Carbon (C)/copper (Cu)-based materials with high thermal conductivity and good stability at high temperatures were developed by adding a small amount of zirconium, which has a low enthalpy of alloy formation with C and Cu. The felt-type C/C composites, which were impregnated by Cu and zirconium, provided 1.4 times higher thermal conductivity at 1300 K than that of the original carbon materials. Microstructural analysis showed that the increase of thermal conductivity is due to the formation of zirconium compounds at the C/Cu interface. These carbon-based materials could be one of the candidate materials for the plasma-facing components of the fusion devices.

An understanding of duplex microstructures encountered during high strength aluminium alloy laser beam melting processing

Many developments on the laser beam melting (LBM) process of hot cracking prone Al alloys are focusing on the addition of Zr or Sc elements. The aim is to promote Al3Zr or Al3Sc precipitation, providing ideal low-energy heterogeneous sites for αAl phase nucleation. A duplex grain microstructure is often induced. Inside one melt pool, the solidification starts at the bottom with an equiaxed structure. Then, at a location around the centre of the pool, a resumption of columnar growth is noticed. The accepted reason in the literature is a variation of nucleant density with melting pool depth. The aim of the current paper is to explain such a behaviour using standard nucleation theory along with the presentation of further experimental data. To this purpose, ZrO2 and Y2O3 particles are added to an aluminium 6061 powder to confirm the assumptions made in a previous work on Yttria-Stabilized Zirconium addition, regarding the effect of zirconium addition on 6061 LBM processing. These experiments are found to provide useful informations for the theoretical nucleation framework. A good correlation has been found between the adapted nucleation model and the variation of the nucleant sites density with encountered thermal conditions. The critical cooling rate necessary to prevent Al3Zr precipitation increases with the concentration of zirconium, which allows an extension of the equiaxed band. The sensitivity of the adapted model parameters is finally discussed to rationalize its applicability.

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 zirconium addition on the phase evolution of chromium zirconium nitride prepared by magnetron sputtering

Abstract In the research reported in this contribution, chromium-zirconium nitride (CrZrN) layers were deposited on (100) silicon wafer by balance magnetron sputtering using argon and nitrogen as working and reactive gas, respectively. The coating layers were categorized into three groups according to zirconium content; low-zirconium (Low-Zr), medium-zirconium (Med-Zr) and high-zirconium (High-Zr). All layers had thicknesses in the range of 1.0-1.3 μm and the Med-Zr was the thickest sample. From the X-ray diffraction (XRD) results, zirconium could partially dissolve in chromium nitride (CrN) and formed complex nitride of chromium-zirconium [(Cr,Zr)N]. This phasic group was dominant for all samples, and the average crystallite sizes decreased with increasing zirconium fraction. In addition, the High-Zr sample had an extra broadened peak among (Cr,Zr)N peaks which could not clearly be identified by XRD. This ambiguity was eliminated by X-ray photoelectron spectroscopy (XPS). It was determined to be amorphous of zirconium oxynitride (Zr2ON2). Because of the high oxygen sensitivity of zirconium, it reacted with nitrogen and residual oxygen forming Zr2ON2. This study is among the first to examine the resulting nanoscale structure of the CrN layers incorporated with a high amount of zirconium.

Effect of zirconium addition on the phase evolution of chromium zirconium nitride prepared by magnetron sputtering

Abstract In the research reported in this contribution, chromium-zirconium nitride (CrZrN) layers were deposited on (100) silicon wafer by balance magnetron sputtering using argon and nitrogen as working and reactive gas, respectively. The coating layers were categorized into three groups according to zirconium content; low-zirconium (Low-Zr), medium-zirconium (Med-Zr) and high-zirconium (High-Zr). All layers had thicknesses in the range of 1.0-1.3 μm and the Med-Zr was the thickest sample. From the X-ray diffraction (XRD) results, zirconium could partially dissolve in chromium nitride (CrN) and formed complex nitride of chromium-zirconium [(Cr,Zr)N]. This phasic group was dominant for all samples, and the average crystallite sizes decreased with increasing zirconium fraction. In addition, the High-Zr sample had an extra broadened peak among (Cr,Zr)N peaks which could not clearly be identified by XRD. This ambiguity was eliminated by X-ray photoelectron spectroscopy (XPS). It was determined to be amorphous of zirconium oxynitride (Zr2ON2). Because of the high oxygen sensitivity of zirconium, it reacted with nitrogen and residual oxygen forming Zr2ON2. This study is among the first to examine the resulting nanoscale structure of the CrN layers incorporated with a high amount of zirconium.

Microstructural and Mechanical behaviour of Nickel Aluminum Bronze alloys

The present investigation reports on microstructure and mechanical characterization of permanent and shell moulded Nickel Aluminum Bronze alloy Castings (NAB) (AB2) melted in Medium Frequency coreless Induction furnace. The mechanical properties studied consisted of Tensile strength, Yield Strength, ductility on one hand, Optical microscopy and grain size measurements on the other. Effect of zirconium addition on the microstructure and mechanical characteristics of Permanent and shell moulded castings have been studied. The results of this investigation reveal that microstructures consisted of dispersed particles in the matrix of copper solid solution both in permanent and shell moulded castings. Shell moulded castings exhibited extensive grain refinement compared to Permanent moulded castings. Very high values of Tensile Strength, Yield strength and Elongation values are obtained for the Nickel Aluminum Bronze alloys. Shell moulded castings have exhibited superior mechanical properties than Permanent moulded castings in all the characteristic/property values obtained.

Effect of Zirconium Addition on High-Temperature Cyclic Oxidation of Diffusion Chromo-Aluminized Ni-Base Superalloy

Nimonic 75 alloy was coated with two different types of coatings: chromo-aluminized coating and Zr-doped chromo-aluminized coating. Diffusion coating was carried out by pack cementation process at 1000 °C for 8 h. Cyclic oxidation tests of Nimonic 75 and its coated specimens were conducted at 900, 1000 and 1100 °C in air for a total period of 100 h. During the first 30-h period, 5-h cycle was applied, and during the 40–100-h period, 10-h cycle was applied. The structures of the coated Nimonic 75 alloy before and after high-temperature oxidation were investigated using light microscopy, scanning electron microscopy/energy-dispersive spectroscopy and X-ray diffraction characterization techniques. The results indicated that Zr-doped chromo-aluminide coating is more effective than chromo-aluminide coating in increasing the oxidation resistance of Nimonic 75 alloy. The parabolic oxidation rate constant kp for cyclic oxidation of uncoated , Cr–Al-coated and Zr/Cr–Al-coated alloys are 1.7, 0.77 and 0.61 10−6 mg2 cm−4 s−1 at 900 °C, and 10.08, 5.2 and 3.91 10−6 mg2 cm−4 s−1 at 1000 °C, and 41.27, 26.69 and 18.13 10−6 mg2 cm−4 s−1 at 1100 °C. The improvement in oxidation resistance by zirconium addition to the chromo-aluminized coating is attributed to its effect on achieving better control of interdiffusion fluxes occurring between coating and substrate so as to reduce Kirkendall effect and voids formation, hence enhancing adhesion, in addition to reducing the outward diffusion of aluminum and stabilizing aluminum oxide scale.

Effect of Zirconium addition on crack, microstructure and mechanical behavior of selective laser melted Al-Cu-Mg alloy

Selective laser melting (SLM) was used to fabricate Al-Cu-Mg alloy and Zirconium-modified Al-Cu-Mg alloy components. The hot-cracking phenomena during the SLM process was significantly reduced by the grain refining effect caused by the addition of Zr. Compared to the Al-Cu-Mg part, the Zr-modified Al-Cu-Mg part with the ultrafine grain exhibits increased yield strength (446±4.3MPa) and ultimate tensile strength (451±3.6MPa). These findings provide a basis for innovative alloy design for SLM.

Effect of zirconium addition on the microstructure and mechanical properties of 15Cr-ODS ferritic Steels consolidated by hot isostatic pressing

The influence of Zr addition on the microstructure and mechanical properties of mechanically alloyed (MA) ODS ferritic steels were studied in this work. The microstructure characteristics included the grain size, oxide particles number densities, size distributions, crystal structures and compositions. TEM foils measurements were complemented by studies of alloys on carbon extraction replica and focus ion beam (FIB) foils. The tensile properties were carried out at different temperatures. The microstructure and mechanical properties were analyzed and compared with nominal compositions (wt.%): Fe-15Cr-2W-0.3Y2O3 and Fe-15Cr −2W-0.3Zr-0.3Y2O3. The experimental revealed that the addition of Zr increased the volume fraction of the smallest and equiaxed ferritic grains, number density of nano-oxide particles and decreased the average size of oxide particles within the ferritic matrix, promoting the formation of fine trigonal δ-phase Y4Zr3O12 nano-oxides and leading to the enhancement of the mechanical properties of the ODS steels.

An Impact of Zirconium Doping of Zn-Al Braze on the Aluminum-Stainless Steel Joints Integrity During Aging

This work offers an analysis of the microstructure and the growth rate of an intermetallic compound within the aged AA 6061 aluminum alloy-304 stainless steel joint brazed with Zn-15Al and Zn-15Al-0.2Zr filler metals. The effect of zirconium addition on mechanical integrity of the brazed joint was studied. The experimental results confirm that the thickness of the Fe-Al intermetallic layer formed at the brazed seam/stainless steel interface increases with the increase of the aging time. Furthermore, it is established that the growth rate of the intermetallic layer for the Zn-15Al-0.2Zr brazed joint was lower than that for Zn-15Al. The results also indicate that the shear strength of both Zn-15Al and Zn-15Al-0.2Zr brazed joints decreases monotonously during aging. The value of the strength after aging lasting for 800 h for Zn-15Al and Zn-15Al-0.2Zr has decreased by 20 and 17%, respectively. The fracture of joints occurred at the interface between the brazed seam and the Fe4Al13 intermetallic layer. The morphology of the surfaces exhibits a cleavage fracture.

Effect of zirconium addition and microstructure refinement on the local magnetic properties of the Nd2Fei4B-based alloys

The effect of Zr addition and microstructure refinement on the local magnetic properties of intermetallic compound Nd2Fe14B in micro- and nano-crystalline alloys was studied by X-ray Magnetic Circular Dichroism. XMCD spectra were measured at the beamline ID-12 of ESRF (Grenoble, France) at the Fe-K and Nd-L3,2 absorption edges in a magnetic field of 10 T at room temperature. The noticeable differences of XMCD amplitude signals, measured on the samples with different content of Zr and various parameters of the microstructure were found, which clearly indicates the influence of the both factors on the magnetic state of Nd and Fe ions in the Nd2Fe14B-based compounds.

The effect of zirconium addition on sintering behaviour, microstructure and creep resistance of the powder metallurgy processed alloy Ti–45Al–5Nb–0.2B–0.2C

Abstract Since the presence of retained β phase might be detrimental for the creep properties of titanium aluminides, elements that stabilize the β phase, e.g. Nb and Mo, can only be used within a limited range. In this work, additions of the neutral element Zr to the alloy Ti–45Al–5Nb–0.2B–0.2C (in at.%) through elemental powder metallurgy were investigated. A powder-metallurgical processing route has been selected for this study, as it appears attractive with respect to microstructural homogeneity and manufacturing costs of complex parts. Different alloys with Zr content varying from 1 to 5 at.% were prepared by uniaxial pressing of a mix of elemental and pre-alloyed powders together with a binder system. The mechanical properties were evaluated by hardness and compression creep tests. The results indicate that Zr significantly decreases the melting point of the base alloy, which directly influences the sintering behaviour and with increasing Zr content the optimum sintering temperature decreases. The creep resistance showed a general improvement with increasing Zr content. The Zr additions resulted in the formation of γ phase enriched with Zr at the colony boundaries, the implications of which are discussed in the paper.

The Effect of Zirconium Addition on the Oxidation Resistance of Aluminide Coatings

Nickel, Mar M247, and Mar M200 superalloys were coated with zirconium-doped aluminide deposited by the chemical vapor deposition method. All coatings consisted of two layers: an additive one, comprising of the β-NiAl phase and the interdiffusion one. The interdiffusion layer on pure nickel consisted of the γ′-Ni3Al phase and β-NiAl phase on superalloys. Precipitations of zirconium-rich particles were found near the coating’s surface and at the interface between the additive and the interdiffusion layer. Zirconium doping of aluminide coating improved the oxidation resistance of aluminide coatings deposited both on the nickel substrate and on the Mar M200 superalloy. Precipitations of ZrO2 embedded by the Al2O3 oxide were formed during oxidation. It seems that the ZrO2 oxide increases adhesion of the Al2O3 oxide to the coating and decreases the propensity of the Al2O3 oxide rumpling and spalling.

Effect of zirconium addition on welding of aluminum grain refined by titanium plus boron

Aluminum oxidizes freely in ordinary atmosphere which makes its welding difficult and weak, particularly it solidifies in columnar structure with large grains. Therefore, it is anticipated that the effect of addition of some grain refiners to its melt before solidification is worth while investigating as it may enhance its weldabilty and improve its mechanical strength. In this paper, the effect of addition of zirconium at a weight of 0.1% (which corresponds to the peretictic limit on the aluminum-zirconium base phase diagram) to commercially pure aluminum, grain refined by Ti+B on its weldability, using gas tungsten arc welding, GTAW, method which was formerly known as TIG. A constant current level of 30 AC Ampere was used because it removes the oxides during the welding process. Metallographic examination of the weldments of the different combinations of Al with Al and Al with its microalloys: in the heat affected zone, HAZ, and away from it was carried out and examined for HAZ width, porosity, cracks and microhardness. It was found that grain refining by Ti+B or Zr resulted in enhancement of the weldment.

Development of New High-Strength and Heat-Resistant Mg-Zn-Y-X (X=Zr and Ag) Casting Alloys

In order to develop a high strength and heat-resistant magnesium alloy, we focused on controlling microstructure of Mg96Zn2Y2 (at %) casting alloy by the addition of a 4th element. Initially, we investigated the effects of zirconium addition and cooling rate for grain refinement on microstructure and mechanical properties. Consequently, Mg95.8Zn2Y2Zr0.2 casting alloy contains fine equiaxed grains (approx. 0.01 mm), and it exhibits tensile and fatigue properties equivalent to or higher than those of commercial aluminum alloys at high temperature above 473 K. At 523 K, this alloy exhibited a tensile strength of 223 MPa nearly twice that of A4032-T6 alloy used in typical automotive pistons. The Mg95.8Zn2Y2Zr0.2 casting alloy also reveals sufficient ductility and good castability, characteristics not common in current heat-resistant magnesium alloys. Next, we focused on controlling microstructure of Mg96Zn2Y2 casting alloy by the addition of Ag. Mg96Zn2Y2 cast alloy is composed of alpha-Mg phase, long-period stacking ordered phase and Mg3Zn3Y2 phase; on the other hand, Mg-Zn-Y-Ag cast alloy had 4th phase by an addition of Ag. A substantial increase in yield strength at room temperature, without grain refining, was the result.

Effects of zirconium addition on microstructure and ablation resistance of carbon fibre reinforced carbon and SiC ceramic matrix composite prepared by reactive melt infiltration

Carbon fibre reinforced C and SiC binary ceramic matrix composites (C/C–SiC) were fabricated by a quick and low cost reactive melt infiltration (RMI) method with Si–Zr25 and Si melts. Effects of zirconium addition in infiltrated Si melt on microstructure and ablation resistance of the composite were investigated. The composite by Si–Zr25 melt infiltration was composed of SiC, ZrC, C and a little amount of ZrSi2 without residual silicon, overcoming the problem of residual silicon in C/C–SiC composite by Si RMI. Compared with the composite by Si melt infiltration, the ablation resistance of the composite by Si–Zr25 was greatly improved by zirconium addition due to ZrO2 and SiO2 protecting layer formed during ablation.