Formation Of Quasicrystalline Phase Research Articles

On electrochemical corrosion of mechano-activated and thermally processed AlxCryNiz 2D decagonal quasicrystalline structures and crystalline approximants

This article represents a pioneering study centered on the corrosion kinetics of untreated and thermally processed mechano-synthesized AlxCryNiz two-dimensional decagonal quasicrystalline structure and crystalline approximants. It sheds light on the distinguished corrosion behavior of untreated and heat-treated mechano-synthesized Al72Cr15Ni13 and Al86Cr12Ni2 alloys, including a wide diversity of miscellaneous intermetallic phases. A comprehensive characterization was performed to analyze crystallographic structure and thermal characteristics of AlxCryNiz powder particles. Electrochemical evaluations of the mechano-synthesized Al72Cr15Ni13 and Al86Cr12Ni2 specimens and their heat-treated counterparts were conducted under cyclic potentiodynamic polarization tests with 0.1 mol/L Na2SO4 (pH=2) and 3.5% NaCl (pH=8.5) electrolytes at room temperature, respectively. Al72Cr15Ni13 two-dimensional decagonal quasicrystalline phase was attained following 6 h mechano-synthesis and subsequent annealing treatment at 1035°C. There is no evidence of quasicrystal formation in the Al86Cr12Ni2 alloy system after 6 h mechano-synthesis and successive thermal processing at 445 and 570°C. In this study, we conducted the first investigation into electrochemical performance of both Al72Cr15Ni13 and Al86Cr12Ni2 intermetallics. Both Al72Cr15Ni13 and Al86Cr12Ni2 alloys develop a protective passive film in 0.1 mol/L Na2SO4 electrolyte. It was determined that 6 h mechano-synthesized Al72Cr15Ni13 sample, subjected to annealing at 1035°C, stands out in the Al-Cr-Ni alloy systems for applications necessitating exceptional corrosion resistance, passivation behavior, and minimal susceptibility to pitting corrosion when compared to other tested counterparts. This alloy is characterized by a corrosion current density of 3.73 µA/cm2 and a corrosion potential of -0.16 V(vs. Ag/AgCl), revealing a remarkably stable passive film up to a current density of 0.02 A/cm2 and a potential of 2.41 V(vs. Ag/AgCl) within 0.1 mol/L Na2SO4 medium. Likewise, it exhibited a drastically diminished corrosion current density of 11.65 µA/cm2 and a reduced corrosion potential of -0.27 V(vs. Ag/AgCl) within 3.5% NaCl electrolyte, attributed to the formation of two-dimensional decagonal quasicrystalline phase and hexagonal δ-Al3Ni2 crystalline approximant at 1035°C. It also encompassed a re-passivation current density and potential of 50.35 µA/cm2 and -0.04 V(vs. Ag/AgCl), respectively, within the latter solution. Its corrosion mechanism may be ascribed to a two-step surface precipitation process: initially, Al dissolves into a hydroxide, succeeded by the formation and precipitation of Al oxides, such as NaAlO2 and Al2O3∙xH2O.

The effect of microwave radiation on the formation of quasi-crystalline phases in the Al- Cu- Fe system prepared by induction furnace

Aluminium- copper- iron quasi-crystals were prepared by melting raw materials and heat treatment process using microwave radiation at three temperatures of 600 °C, 700 °C, and 800 °C. Al- Fe alloy and Al- Cu alloy were prepared separately, then these two alloys were melted in an induction furnace. X-ray diffraction, scanning electron microscopy, and simultaneous thermal analysis were used to investigate the microstructural characteristics, fracture surface, and thermal behaviour. In these samples, the peaks related to the quasi-crystalline phase, θ, β- AlFe(Cu), λ- Al13Fe4, and ω-Al7Cu2Fe1 phase were detected. The intensity of the formed phases also changed with the temperature and duration of the heat treatment process. By performing the heat treatment process at 600 °C, the intensity of the peaks related to the quasi-crystalline phase has increased and the peaks related to the θ phase have completely disappeared. Also, by increasing the annealing temperature to 700 °C, the intensity of the peaks related to the quasi-crystalline phase increased compared to the sample annealed at 600 °C, but annealing at 800 °C reduced the intensity of quasi-crystalline phase peaks and λ- Al13Fe4 phase is completely dissolved, but some phases such as β- AlFe(Cu) and ω still remained, which implies these phases are stable even up to 1000 °C. The morphology of the quasi-crystalline was cauliflower with ridges on the fracture surface of the sample while uneven surfaces were in the form of quasi- cleavage. These results show that the quasi-crystalline phase can be developed in a much shorter time using microwave energy compared to common annealing methods.

Ball Milling and Consolidation Process of Al-Cr Powder Mixture—Microstructural Characterization

The interest in studying the synthesis of an Al–Cr alloy system by non-equilibria processes is due to the formation of metastable or quasicrystalline phases when rapid solidification has been utilized. Similarly, the formation of quasicrystals has been reported to a much lesser extent when the mechanical alloying technique was applied. In the present research, a mixture of powders of Cr and Al (both elements with a purity of 99.99%) with compositions of Al-5 and 7.5 at. % Cr was subjected to a ball milling process. Afterwards, the powder mixture was subjected to a consolidation process, conducted by pressing and sintering processes. The X-ray diffraction analyses revealed that during 20 h of milling there was no formation of metastable or quasicrystalline second phases detected. In addition, the X-ray diffraction peaks revealed that as milling time increased, the nanometric grain size decreased, and once the sintering treatment was applied, the crystallite size decreased following the same tendency. The dislocation density was estimated using the size of nanometric grains; this computation revealed that the dislocation density grew throughout the ball milling process; even after sintering, the multiplication of dislocations prevailed following the same tendency.

Heat-Resistant Al-Alloys with Quasicrystalline and L1<sub>2</sub>- Precipitates

We have been developing Al-Mn-Cu based alloys alloyed with minor additions of different elements. Small additions of beryllium enhance the formation of the icosahedral quasicrystalline phase (IQC) during solidification, especially during ageing. Upon solidification, primary IQC-particles may form, with sizes, ranging from 5 to 50 μm. IQC is also present as a part of binary eutectic in the interdendritic regions. More importantly, nanosized quasicrystalline precipitates can form during T5-treatment at temperatures ranging from about 250−450 °C. They are, in fact, metastable precipitates transforming to ternary T-precipitates (Al20Mn3Cu2) phase above 450 °C. The heat resistance can be increased considerably by the addition of Sc and Zr by forming L12-precipitates in spaces between quasicrystalline precipitates. In this paper, we studied three alloys, two Al-Mn-Cu-Be alloys and an Al-Mn-Cu-Be-Sc-Zr alloy. The alloys were produced by vacuum induction melting and casting into a copper mould. We investigated the response of the alloys to different heat treatments and their heat resistance at higher temperatures. It was shown that the alloys could be precipitation strengthened by ageing at 300 °C and 400 °C. The hardness of the alloy stayed at relatively high levels even at 500 °C, while more substantial softening occurred at 600 °C.

First-time synthesis of an unparalleled Al72Cr15Ni13 decagonal quasicrystalline phase with the help of mechanical alloying and annealing procedures: A comparative study

An X-ray diffractometer, a field-emission scanning electron microscope, and a high-resolution transmission electron microscope were utilized to characterize the structural and microstructural evolutions of the AlCrNi alloy powders. The single-phase Cr (Al, Ni) nanostructured solid-solution was synthesized through the high-energy planetary ball milling in 96 h. It was turned out that the decagonal quasicrystal obtains after the annealing treatment at 1035 °C. The formation of the decagonal quasicrystalline phase in the AlCrNi alloy system was first investigated in the present article. A differential thermal analyzer was employed for the examination of the thermal performance of the AlCrNi alloy powders. The specific surface area of the mechanically alloyed and heat-treated AlCrNi alloy powders was determined through the BET analysis without any further alkali leaching. The specific surface area of the AlCrNi alloy powders containing the decagonal quasicrystalline phase possesses a high value of 1.75 m2g−1.

Heat Treatment in an Alloy Al63Cu24Fe12

Aluminum-based alloys containing quasicrystalline phases have good wear resistance due to their low wear coefficient and high hardness. The formation of quasicrystalline phases depends on the composition of the alloy and the imposition of high cooling rates on the molten metal. In the raw state of fusion, presenting β-type and Al13Fe4 monoclinic phases, they are present together with the quasicrystalline phase. A careful chemical composition control and an efficient heat treatment are necessary to obtain quasicrystalline phases. The objective of this work was to study the heat treatment in the homogenization of the quasicrystalline alloy Al64Cu27Fe15 obtained by smelting, in a controlled atmosphere. To understand the microstructural evolution, characterizations were made using SEM and XRD. The thermal treatment carried out for 24 hours, to obtain a microstructure with icosaedral phase coexisting with small increases in existing crystalline phases.
 
 Keywords: Quasicrystalline Phases. Microstructural Evolution. Phases of type β and Al13Fe4.

Synthesis and stability of quasicrystalline phase in Al-Cu-Fe-Si mechanically alloyed powders

The effect of Si addition on a quasicrystalline phase formation in Al-Cu-Fe-Si alloys prepared by mechanical alloying has been investigated using X-ray diffraction and scanning and transmission electron microscopy. Two compositions containing 10 at.% of Si were selected to verify the influence of the e/a ratio on a sequence of phase formation during milling: Al58.5Cu18Fe13.5Si10 (e/a = 1.98) and Al53.5Cu19.5Fe17Si10 (e/a = 1.75). A quasicrystalline icosahedral phase (i-phase) was found in both alloys after 10 h of milling in the form of nano-quasicrystallites with the size of 10–20 nm. Addition of Si stabilized the quasicrystalline phase being dominant after prolonged milling time, contrary to the reference ternary Al65Cu20Fe15 powder, which apart of the quasicrystalline phase contained the cubic β-Al(Cu, Fe) phase. Thermal stability of the quasicrystalline phase in the powders milled for 10 h was examined after annealing at 800 °C for 4 h. The i-phase was preserved partially in Al53.5Cu19.5Fe17Si10 and reference Al65Cu20Fe15 powders (both with a ratio e/a = 1.75), which coexisted with β-Al(Cu, Fe) and Al13Fe4 phase or α-Al55Si7Cu25.5Fe12 and Al2Fe3Si3 phases in Al65Cu20Fe15 and Al53.5Cu19.5Fe17Si10, respectively. For the Al58.5Cu18Fe13.5Si10 powders (e/a = 1.98), the annealing led to complete transformation of the i-phase to the cubic α-Al55Si7Cu25.5Fe12.5 approximant, forming crystallites with a size of 100–300 nm.Graphical abstract

Heat Treatment in an Alloy Al64Cu27Fe15

Aluminum-based alloys containing quasicrystalline phases have good wear resistance due to their low wear coefficient and high hardness. The formation of quasicrystalline phases depends on the composition of the alloy and the imposition of high cooling rates on the molten metal. In the raw state of fusion, presenting β-Al2Fe5(Cu) monoclinic phases, they are present together with the quasicrystalline phase-ω. A careful chemical composition control and an efficient heat treatment are necessary to obtain quasicrystalline phases. The objective of this work was to study the heat treatment in the homogenization of the quasicrystalline alloy Al64Cu27Fe15 obtained by smelting, in a controlled atmosphere. To understand the microstructural evolution, characterizations were made using SEM and XRD. The thermal treatment carried out for 24 hours, to obtain a microstructure with icosahedral phase coexisting with small increases in existing crystalline phases. DOI: http://dx.doi.org/10.17807/orbital.v12i4.1581

Investigation of Quasicrystalline Phases Formation by mechanical Alloying of the Al - Cr and Al - Fe Alloys (Dept.P)

Mechanical alloying (MA) of elemental Al and Cr powders of nominal composition Al86Cr14 has been performed by using a conventional ball – mill. The MA process produced a supersaturation of Cr in Al. Isothermal annealing at 590 °C represented in the formation of quasicrystalline phase, in addition of two intermetallic phases Al13C2 and Al14.Cr. A supersaturation solid solution of a α- Fe (AI) and a metastable Al6 Fe phase were formed by MA of a mixture of Al and Fe elements containing of nominal composition Al84 Fe16. However, thermal treatment fail to produce the quasi-phase, various intermetallic phase are obtained. For both alloy systems, milling structure have a nano size of ≈25 nm for Al86Cr14 and ≈37 nm for Al84Fe16, the thermal stability of the produced phases was also examined.

2Investigation of Al26.5Cu25Fe12.5Quasicrystalline Phase Formation by Rapid Solidification Followed by Mechanical Milling (Dept.P)

The formation of the quasicrystalline phase Al62.5 Cu25FC12.5, by twin rolls rapid solidification technique has been investigated. The obtained phases are cauterized by XRD, Differential Thermal Analysis and electrical resistivity measurements. The effect of milling on the sample produced by rapid solidification is also examined. A quenched sample, a quasicrystalline (i-phase) is present in a relatively high volume fraction, in addition to two other phases that are most likely Al2Cu to be phase and Al7Cu2Fe phase (𝟂-phase). The milled samples does not give a single quasicrystalline phase, but the milling tends to stabilize the pre- existed i-phase.

Ultrafast synthesis of the nanostructured Al59Cu25.5Fe12.5B3 quasicrystalline and crystalline phases by high-energy ball milling: Microhardness, electrical resistivity, and solar cell absorptance studies

In this study, the Al59Cu25.5Fe12.5B3 nanoquasicrystalline alloy and related crystalline phases were synthesized through mechanical alloying using a high-energy ball milling and consolidated by a cold isostatic pressing apparatus. This paper focuses on the synthesis, structural and microstructural evolutions, thermal stability, microhardness, and electrical and optical properties of the Al59Cu25.5Fe12.5B3 nanoquasicrystalline alloy for solar selective absorber usages. The structural evolutions of the mechanically alloyed and heat-treated AlCuFeB powders were investigated by X-ray diffractometry. Accordingly, the effect of milling time and heat treatment on the formation of quasicrystalline and related crystalline phases were studied in the AlCuFeB alloy system. The microstructure, morphology, and chemical microanalysis of the un-milled and as-milled powders were examined by field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The composition of the as-milled AlCuFeB powders was estimated employing inductively coupled plasma-atomic emission spectroscopy. The thermal stability of the AlCuFeB powders was recorded by differential thermal analysis, and the weight gain of the particles during annealing was investigated through thermogravimetric analysis. The nanostructured Al59Cu25.5Fe12.5B3 stable quasicrystalline phase and crystalline Al(Cu,Fe) solid-solution were synthesized by the ultrafast milling procedure in 1 h. The rationale behind using the term ultrafast synthesis is to synthesize the QC i-phase only by the high-energy ball milling procedure in short-term ball milling without subsequent annealing treatment. However, the single quasicrystalline phase could not be obtained even after the annealing treatment. The quasicrystalline size was calculated by the Williamson–Hall method and optimized by the Rietveld refinement procedure, and it was found that the size is varied between 53 and 61 nm. Furthermore, the particle size distribution of the as-milled AlCuFeB powders was measured using laser static light scattering, which ranges from 0.1 to 50 μm. The microhardness of the consolidated as-milled and heat-treated samples was estimated utilizing the Vickers microhardness indenter. At the same time, their electrical resistivity was assessed by the four-point probe method at room temperature. The spectral analyses of absorption on the consolidated as-milled samples were carried out in the ultraviolet, visible, and near-infrared regions. It was found that the presence of the quasicrystalline phase in the AlCuFeB alloy prominently improves the microhardness, electrical resistivity, and particularly sunlight absorptance.

Structure and corrosion resistance of Al–Cu–Fe alloys

The microstructure and electrochemical properties of Al–Cu–Fe alloys with the atomic compositions of Al65Cu20Fe15, Al78Cu7Fe15 and Al80Cu5Fe14Si1 have been studied. The alloys were produced by induction melting of pure elements with copper mold casting. The microstructure of the alloys was analyzed by X-ray diffraction and high-resolution transmission electron microscopy. The formation of quasicrystalline phases in the Al–Cu–Fe alloys was confirmed. The presence of intermetallic phases was observed in the alloys after crystallization in a form of ingots and plates. The electrochemical measurements were conducted in 3.5% NaCl solution. The electronic structure of the alloys was determined by X-ray photoelectron spectroscopy. The post corrosion surface of the samples was checked using a scanning electron microscope equipped with the energy-dispersive X-ray detector. It was observed that the Al65Cu20Fe15 alloy had the highest corrosion resistance. The improved corrosion resistance parameters were noted for the plate samples rather than those in the as-cast state. And the hardness of the Al65Cu20Fe15 alloy was significantly higher than the other alloy samples.

The Effect of Transition Metals on Quasicrystalline Phase Formation in Mechanically Alloyed Al65Cu20Fe15 Powder

The Effect of Transition Metals on Quasicrystalline Phase Formation in Mechanically Alloyed Al65Cu20Fe15 Powder

Correlated Unique Variation of Electrical Resistivity to Crystallization Behavior of the Zr52.5Cu17.9Ni14.6Al10Ti5 Metallic Glass

Due to the differences between the glass and crystalline phases, crystallization of metallic glass occurs with heat release, volume shrinkage, and electrical resistivity drastic changes. Electrical resistivity of the Zr52.5Cu17.9Ni14.6Al10Ti5 metallic glass during crystallization was investigated under both continuous heating and isothermal annealing. This amorphous alloy exhibits a continuous variation instead of sharp decline when reaches the onset crystallization temperature. This unique variation was found to be related to the formation of a few quasicrystalline phases. The slower phase transformation process of this metallic glass brings lots of grain boundaries, which results in increasing of resistivity at the last stage during isothermal annealing. These results imply that electrical resistivity measurement is a more intuitive approach to investigate structure evolution of metallic glasses.

Quasicrystalline Phase Formation of the Al67Cu26Fe15 Alloy

O presente trabalho teve como objetivo caracterizar a microestrutura da fase icosaedral (f-fase quasicristalina) do sistema com composição estequiométrica do quasicristal Al67Cu26Fe15. A liga ternária com composição nominal de Al67Cu26Fe15 foi processada por Moagem Mecânica de Alta Energia, como um método viável de processamento no estado sólido para a produção de várias fases quasicristalinas metaestáveis e estáveis. A caracterização estrutural das amostras obtidas foi realizada por difração de raios-X (DRX) e Microscopia Eletrônica de Varredura (MEV), enquanto a composição elementar dos elementos químicos Al, Fe e Cu foram determinados pela técnica de Espectroscopia de raios X por energia dispersiva (EDS). Na superfície da liga quasicristalina, podemos observar no SEM a presença da alumina g-Al2O3, que contribui para as propriedades texturais de suporte catalítico deviso a sua atividade catalítica, visando maior desempenho em reações de oxidação do metanol. De acordo com os resultados de XRD, os padrões de difração da liga Al67Cu26Fe15 mostraram a presença das fases w-Al7Cu2Fe, b-Al(Fe;Cu) e l-Al13Fe4 coexistem com a f-fase quasicristalina em regime termodinâmico. Finalmente, a análise elementar indica que durante a síntese da liga existe pequena variação da composição ideal. Os resultados indicam que ligas com alto percentual de fase icosaedral podem ser obtidas por fundição ao ar.

Microstructure and mechanical behavior of Al92Fe3Cr2X3 (X = Ce, Mn, Ti, and V) alloys processed by centrifugal force casting

Microstructural and mechanical characterization of Al92Fe3Cr2X3 (X=Ce, Mn, Ti, and V) alloys were performed. The alloys were processed by a method that uses centrifugal force to cast the samples into a rotating copper mold. Microstructural characterization was carried out by means of x-ray diffraction, scanning electron microscopy, and differential scanning calorimetry. Compressive tests at room and at 300°C were performed in selected samples to evaluate their mechanical properties. Microstructural characterization showed the formation of quasicrystalline phases as well as other intermetallic phases embedded within an Al-FCC matrix. The Ce-containing alloy exhibited promising results regarding quasicrystalline phase formation and stability as well as with respect to its mechanical properties at high temperatures. The quasicrystalline phase of this alloy appears to be stable up to 545°C when the DSC reveals an exothermic transformation. In addition, the presence of a eutectic structure surrounding the Al-FCC grains enhanced the mechanical strength of this alloy. At 300°C, the Ce-containing alloy showed yield strength and ultimate tensile strength of 180MPa and 360MPa, respectively. If compared to a commercial aluminum alloy 2024 at the T6 condition, close to 300°C, the alloy studied here showed an increase of more than 4 times in the yield strength, and almost 7 times in the ultimate tensile strength. The high thermal stability and mechanical properties at high temperatures of this alloy open interesting possibilities for further studies and future applications of this Al-Fe-Cr-Ce alloy.

Formation of Quasicrystalline Phases and Their Close Approximants in Cast Al-Mn Base Alloys Modified by Transition Metals

The aim of the presented research was to study the influence of Cr, Co, Ni, and Cu additions on the formation of quasicrystalline particles in the 94Al-6Mn base alloy during casting at intermediate cooling rates. Based on the obtained results, Cu and Ni enhance quasicrystalline phase nucleation compared to the unmodified binary composition. In the case of Cu addition, formation of a quasicrystalline phase takes place along whole thickness of the prepared casting, but its fraction and morphology depends on the cooling rates present in different parts of the sample. Based on the previous works on the beneficial effect of Fe addition, a quaternary alloy containing both Fe and Cu was prepared to evaluate the effect of the simultaneous presence of these elements on the microstructure of the obtained castings.

Icosahedral Quasicrystal Layer Observed on λ Phase in Al-Cu-Fe Alloy

Icosahedral quasicrystals display irregular shape if it is embedded in bulk material. If it has free surface, it has well-defined facets, reflecting its unique 5-, 3-, and 2-fold rotational symmetries. In this study, an Al-Cu-Fe alloy with nominal composition of Al65Cu20Fe15 was prepared by arc melting and the microstructure was studied by using Scanning Electron Microscope, Energy Dispersive X-ray Spectroscopy, and Electron Back Scattering Diffraction (EBSD). On the surface of λ crystalline phase, an extra layer is found. EBSD from this layer revealed 5-, 3-, and 2-fold rotational symmetries, demonstrating the icosahedral quasicrystalline structure. Further, it has been found that the icosahedral quasicrystalline extra layer and the λ substrate have orientation relationship revealed by the coincidences of Kikuchi bands and poles on the EBSD patterns. This report is important to future studies regarding the formation of icosahedral quasicrystalline phase and thin film preparation related to icosahedral quasicrystalline phase.

Assessment of phase constitution on the Al-rich region of rapidly solidified Al-Co-Fe-Cr alloys

The formation of quasicrystalline approximants in rapidly solidified Al-Co-Fe-Cr alloys was investigated. Alloys of atomic composition Al71Co13Fe8Cr8, Al77Co11Fe6Cr6 and Al76Co19Fe4Cr1 were produced using melt spinning and arc melting methods and their microstructural characterization was carried out by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Up to the present there is no consensus in the literature regarding the formation of quasicrystalline phase or quasicrystalline approximants in the Al71Co13Fe8Cr8 alloy. This work presents, for the first time, a detailed structural characterization of selected alloys in the Al-Co-Fe-Cr system close to the atomic composition Al71Co13Fe8Cr8. The results indicated the samples to be composed, mostly, by two intermetallic phases, which are quaternary extensions of Al5Co2 and Al13Co4 and are quasicrystalline approximants. Although the Al5Co2 phase has already been reported in the Al71Co13Fe8Cr8 alloy, the presence of the monoclinic Al13Co4 is now identified for the first time in the as cast state. In the binary Al-Co system a quasicrystalline phase is known to form in a rapidly solidified alloy with composition close to the monoclinic and orthorhombic Al13Co4 phases. This binary quasicrystalline phase presents an average valence electron per atom (e/a) between 1.7 and 1.9; thus, in addition to the Al71Co13Fe8Cr8 alloy, the compositions Al77Co11Fe6Cr6 and Al76Co19Fe4Cr1 were chosen to be within the region of formation of the quaternary extension of the Al13Co4 phase and also within the (e/a) of 1.7 to 1.9. However, no quasicrystalline phase is present in any of the studied alloys. The Al-Co-Fe-Cr system, around the compositions studied, is composed of quaternary extensions of Al-Co intermetallic phases, which present solubility of Fe and Cr at Co atomic sites.

Effect of Cr addition on the formation of the decagonal quasicrystalline phase of a rapidly solidified Al-Ni-Co alloy

Abstract The influence of Cr addition in a rapidly solidified Al-Ni-Co alloy was investigated. Melt spun samples of atomic composition Al71Ni20Co9, Al72Ni19Co7Cr2 and Al72Ni20Co5Cr3 were studied by X-ray diffraction and transmission electron microscopy. Aiming to develop quasicrystalline compositions enriched in corrosion resistant elements such as Cr and Ni this work presents, for the first time, the effect of Cr addition on the quasicrystalline phase formation of a high-Ni Al-Ni-Co rapidly solidified alloy chosen to be within the range of formation of the decagonal quasicrystalline phase observed in this ternary system. The composition of the quaternary alloys was chosen by reducing the Co content in favor of Cr on the ternary alloy and keeping the average valence electron per atom (e/a) around 1.86. The phase constitution of the ternary alloy consisted of the decagonal phase along with two intermetallic phases, Al3Ni and Al3Ni2. The addition of Cr resulted in the formation of a second quasicrystalline decagonal phase, rich in Cr. This was due to the low Cr solubility on the ternary Al-Ni-Co decagonal and intermetallic phases, which rejected Cr and resulted on the formation of the Cr-rich quasicrystal.