Effect of Mg on Solidification Microstructures of Homogenous and Functionally Graded A390 Aluminum Alloys

Hypereutectic Al?CSi alloys are used in components that require high resistance wear and corrosion, good mechanical properties, low thermal expansion and less density. The size and morphology of hard primary silicon particles present in Al?CSi alloys greatly influences the mechanical properties. Addition of Mg leads to formation of intermetallic Mg₂Si phases, which contributes towards the properties of high silicon alloy as well as alters the nature and quantity of primary silicon formed. The high silicon alloy subjected to centrifugal casting leads to the formation of functionally gradient material, which provides variation in spatial and continuous distribution of primary phases in a definite direction exhibiting selective properties and functions within a component. The present study is to evaluate the effect of Mg on solidification microstructures of homogenous and functionally graded A390 aluminium alloys. The addition of Mg from 3 to 5?% in A390 alloy using Al?C20Mg master alloy has shown a transformation from primary silicon rich matrix to Mg₂Si rich matrix. Centrifugal casting shows the gradient distribution of primary silicon and Mg₂Si phases towards the inner periphery of the casting.     

Effect of Compositional Variation on the Microstructural Evolution and the Castability of Al–Mg–Si Ternary Alloys

This study examined the microstructural evolution and castability of Al–Mg–Si ternary alloys with varying Si contents. Al–6Mg–xSi alloys (where x = 0, 1, 3, 5, and 7; all compositions in mass pct) were examined, with Al–6 mass pct Mg as a base alloy. The results showed that in the ternary alloys with Si ≤ 3 pct, the solidification process ended with the formation of eutectic α-Al–Mg₂Si phases generated by a univariant reaction. However, in the case of ternary alloys with Si > 3 pct, solidification was completed with the formation of α-Al–Mg₂Si–Si ternary eutectic phases generated by a three-phase invariant reaction. In addition to the eutectic Mg₂Si phases, the primary Mg₂Si phases formed in each of the ternary alloys, and the size of both sets of phases increased with increasing Si content. The two-phase eutectic α-Al–Mg₂Si nucleated from the primary Mg₂Si phases. The inoculated Al–6Mg–1Si alloy had the smallest grain size. Moreover, the grain-refining efficacy of the Al–5Ti–B master alloy in the ternary alloys decreased with increasing Si content in the alloys. Despite the poisoning effect of Si on the potency of TiB₂ compounds in the inoculated Al–6Mg–1Si alloy, the grain size of the alloy was slightly smaller than that of the Al–6Mg binary alloy. This resulted from the increasing growth restriction factor (induced by Si addition) of the Al–6Mg–1Si alloy. In terms of the castability, the examined alloys showed different levels of susceptibility to hot tearing. Among the alloys, the ternary Al–6Mg–5Si alloy exhibited the highest susceptibility to hot tearing, whereas the Al–6Mg–7Si exhibited the lowest. The severity of hot tearing initiated by the unraveling of the bifilm was determined by the freezing range, grain size, and the amount of eutectic phases at the end of the solidification process.

     

Microstructural evolution and hardness property of in situ Al–Mg2Si composites using one-step gravity casting method

In the present investigation, Al–X?wt-% Mg₂Si (X?=?0, 5, 10, 15 and 20) in situ composites are successfully synthesised by one-step gravity casting technique. Commercially pure Al, Mg and Si are used as raw materials. Microstructural evaluation and correlation of micro- and bulk hardness properties have been studied on developing composites. The composites consist of mainly three phases: matrix (α-Al), reinforcing (primary Mg₂Si) and binary eutectic (Al–Mg₂Si) phase. Primary Mg₂Si particles are formed by pseudo-eutectic transformation during solidification and surrounded by matrix and binary eutectic phase. It is found that Mg₂Si concentration has a significant impact on morphology and volume per cent of the above-mentioned phases. Primary Mg₂Si particles’ size and volume per cent increase with increasing wt-% of Mg₂Si. Volume per cent of individual phases and Mg₂Si concentration have great impact on hardness properties of composites. Bulk hardness increases with increasing wt-% of Mg₂Si concentration, but micro-hardness of primary Mg₂Si particle decreases slightly. Mg₂Si concentration also has significant impact on micro-hardness of individual phases.     

Application of electromagnetic separation of phases in alloy melt to produce <Emphasis Type="Italic">In-situ</Emphasis> surface and functionally gradient composites

The principle of electromagnetic separation of phases (primary phase) in alloy melt is that the electromagnetic force scarcely acts on the primary phases due to its low electric conductivity as compared to the melt. As a result, a repulsive force acts on the primary iron-rich phases to push them to move in the direction opposite to that of the electromagnetic force. The in-situ surface composite and the functionally gradient composite reinforced by primary Si are produced when the hypereutectic Al-Si alloy solidifies under electromagnetic force induced by static magnetic field and DC current. Similarly, the Al-Si-1.20 pct Fe-1.60 pct Mn alloy in-situ surface composite reinforced by primary iron-rich phase is produced. Based on this, a new method for production of in-situ multigradient composite with several layers, by electromagnetic separation of phases and directional solidification technique, is proposed.     

Study on electromagnetic force for preparation of in-situ Al/Mg2Si functionally graded materials by electromagnetic separation method

The aim of this article is to investigate the effects of electromagnetic force on primary particle distribution of in-situ Al/Mg₂Si functionally graded materials (FGMs) by electromagnetic separation method. Experimental results show that there is a critical value of electromagnetic force. The FGMs can be produced only when the electromagnetic force is beyond the critical value. With increasing the electromagnetic force, the particle volume fraction of the particle-packed regions increases, the length of the particle-packed regions decreases, the average gradient of particle volume fraction increases, and the primary particle size become smaller.     

Hardness and electrical resistivity of Al–13 wt % Mg<Subscript>2</Subscript>Si pseudoeutectic alloy

In the present work, effect of growth rates on microhardness, electrical properties and microstructure for directionally solidified Al–13 wt % Mg₂Si pseudoeutectic alloy at a constant temperature gradient were studied. Directional solidification process were carried out with five different growth rates (V = 8.33–175.0 μm/s) at a constant temperature gradient (G = 6.68 K/mm) by using a Bridgman type directional solidification furnace. Microstructure of directionally solidified Al–13 wt % Mg₂Si pseudoeutectic alloy was observed as Mg₂Si coral-like structure phase dispersed into primary α-Al phase matrix. The electrical resistivity for Al–13 wt % Mg₂Si pseudoeutectic alloy, were measured by the d.c. four-point probe method. The dependency ofmicrohardness and electrical resistivity on growth rates were obtained as HV = 135.7 (V)^0.09 and ρ = 17.30 × 10^?8(V)^0.08, respectively for Al–Mg₂Si pseudoeutectic alloy. The results obtained in present work were compared with the previous similar experimental results.     

Characterization of a diffusion-bonded Al-Mg alloy/SiC interface by high resolution and analytical electron microscopy

The interfacial structure of a diffusion-bonded Al-4.55 at. pct Mg/SiC interface was examined by conventional and high-resolution transmission electron microscopy. Formation of Mg₂Si, MgO, and Al₂MgO₄ was observed. The monoclinic Mg₂Si phase formed at the Al/SiC interface, while the oxides MgO and Al₂MgO₄ formed at the monoclinic Mg₂Si/Al interface. It is shown that the formation of these phases can be predicted using simple thermodynamic criteria such as the relative bond strengths between Al, Si, C, O, and Mg. In addition, precipitation of some equilibrium Al₈Mg₅ precipitate was also observed at the interface. The interfacial structure observed in the Al-Mg/SiC system is contrasted with that observed in the pure Al/SiC system.     

Twin Roll Casting of Al-Mg Alloy with High Added Impurity Content

The microstructural evolution during twin roll casting (TRC) and downstream processing of AA5754 Al alloy with high added impurity content have been investigated. Strip casts with a high impurity content resulted in coarse α-Al grains and complex secondary phases. The grain size and centerline segregation reduced significantly on the addition of Al-Ti-B grain refiner (GR). Coarse-dendrite arm spacing (DAS) “floating” grains are observed in the impure alloy (IA) with higher volume in the GR strips. Two-dimensional (2D) metallographic analysis of the as-cast strip suggests that secondary phases (Fe-bearing intermetallics and Mg₂Si) are discrete and located at the α-Al cell/grain boundaries, while three-dimensional (3D) analysis of extracted particles revealed that they were intact, well interconnected, and located in interdendritic regions. Homogenizing heat treatment of the cast strip breaks the interconnective networks and modifies the secondary phases to a more equiaxed morphology. During rolling, the equiaxed secondary phases align along the rolling direction. X-ray diffraction (XRD) analysis suggests that α-Al(FeMn)Si and Mg₂Si are the predominant secondary phases that are formed during casting and remain throughout the downstream processing of the GR-IA. The high-impurity sheet processed from TRC resulted in superior strength and ductility over the sheet processed from small book mold ingot casting. The current study has shown that the TRC process can tolerate higher impurity levels and produce formable sheets from the recycled aluminum for structural applications.     

Formation of solidification microstructures in centrifugal cast functionally graded aluminium composites

A large number of engineering components and structures demand location specific performance under service conditions. A gradual transition in the microstructure or composition can motivate the changes in the functions of the specific locations for meeting the requirements and these tailored materials are termed as functionally graded materials (FGM). Centrifugal casting has emerged as the simplest and cost effective technique for producing large size engineering components of functionally graded metal matrix composites. The present paper describes the formation of different types of gradient solidification microstructures in SiC, B₄C, SiC-graphite hybrid, primary silicon, Mg₂Si and Al₃Ni reinforced functionally graded aluminium composites processed by centrifugal casting and correlate the microstructures with materials and processing parameters. The densities and size of the reinforcements play a major role in the formation of graded microstructures, the high density particles/phases both SiC and Al₃Ni form gradation towards the outer periphery and low density particles like graphite, primary silicon and Mg₂Si form gradation towards inner periphery. The B₄C particle having closer density to Al alloy has given more scattered distribution compare to other systems. However, functionally graded composite containing the SiC and Graphite particles has shown gradation towards inner periphery.     

Solidification and Microstructural Evolution of Hypereutectic Al-15Si-4Cu-Mg Alloys with High Magnesium Contents

The low coefficient of thermal expansion and good wear resistance of hypereutectic Al-Si-Mg alloys with high Mg contents, together with the increasing demand for lightweight materials in engine applications have generated an increasing interest in these materials in the automotive industry. In the interests of pursuing the development of new wear-resistant alloys, the current study was undertaken to investigate the effects of Mg additions ranging from 6 to 15 pct on the solidification behavior of hypereutectic Al-15Si-4Cu-Mg alloy using thermodynamic calculations, thermal analysis, and extensive microstructural examination. The Mg level strongly influenced the microstructural evolution of the primary Mg₂Si phase as well as the solidification behavior. Thermodynamic predictions using ThermoCalc software reported the occurrence of six reactions, comprising the formation of primary Mg₂Si; two pre-eutectic binary reactions, forming either Mg₂Si + Si or Mg₂Si + α-Al phases; the main ternary eutectic reaction forming Mg₂Si + Si + α-Al; and two post-eutectic reactions resulting in the precipitation of the Q-Al₅Mg₈Cu₂Si₆ and θ-Al₂Cu phases, respectively. Microstructures of the four alloys studied confirmed the presence of these phases, in addition to that of the π-Al₈Mg₃FeSi₆ (π-Fe) phase. The presence of the π-Fe phase was also confirmed by thermal analysis. The morphology of the primary Mg₂Si phase changed from an octahedral to a dendrite form at 12.52 pct Mg. Any further Mg addition only coarsened the dendrites. Image analysis measurements revealed a close correlation between the measured and calculated phase fractions of the primary Mg₂Si and Si phases. ThermoCalc and Scheil calculations show good agreement with the experimental results obtained from microstructural and thermal analyses.     

Combined Effect of Calcium and Silicon on the Phase Composition and Structure of Al–10%Mg Alloy

Phase transformations in the Al–Ca–Mg–Si system in the region of aluminum–magnesium alloys are investigated using the Thermo-Calc program. The liquidus projection of the quaternary system is constructed with a Mg content of 10% and it is shown that phases Al4Ca, Mg₂Si, and Al₂CaSi₂ can crystallize (in addition to the aluminum solid solution (Al)) depending on the calcium and silicon concentrations. The crystallization character of quaternary alloys is investigated with the help of a polythermal cross section calculated at concentrations of 10% Mg and 84% Al. Based on the analysis of phase transformations occurring in alloys of this section, the presence of the Al–Al₂CaSi₂–Mg₂Si quasi-ternary section in the Al–Ca–Mg–Si system was assumed. Three experimental alloys were considered from a quantitative analysis of the phase composition, notably, Al–10% Ca–10% Mg–2% Si, Al–4% Ca–10% Mg–2% Si, and Al–3% Ca–10% Mg–1% Si. Metallographic investigations and electron-probe microanalysis were performed using a TESCAN Vega 3 scanning electron microscope. Critical temperatures are determined using a DSC Setaram Setsys Evolution differential calorimeter. The experimental results agree well with the calculated data; in particular, a peak at t ~ 450°C is revealed for all alloys in curves of the nonequilibrium solidus and invariant eutectic reaction L → (Al) + Al₄Ca + Mg₂Si + Al₃Mg₂. It is established that the structure of the Al–3% Ca–10% Mg–1% Si alloy is closest to the eutectic alloy. It is no worse that the AMg10 alloy in regards to density and corrosion resistance and even surpasses it in hardness, which allows us to consider this alloy as the basis for the development of a new cast material: “natural composites.”     

Development of In Situ As Cast Al–Mg2Si Particulate Composite: Microstructure Refinement and Modification Studies

In situ processed hypereutectic Al?CMg₂Si composites are reported as potential replacements for Al?CSi?CMg heat-treated alloys in specific automotive applications like brake discs, cylinder heads and piston heads. Experiments were conducted for preparing as cast hypereutectic Al?C15?%Mg₂Si alloy, with 8?% extra silicon. The alloy microstructure revealed a dendritic morphology of ??-Al, primary (P)-Mg₂Si particles and Fe rich inclusions embedded in the ternary eutectic matrix. Addition of conventional grain refiner Al?C5Ti?C1B (1?%wt) lead to refinement of P-Mg₂Si dendrites to faceted hopper-like polyhedral particles of ~30???m in size. Addition of combination of B-rich grain refiner Al?C1Ti?C2B and phosphorous, resulted in finer (~20???m), dense and fairly uniformly distributed P-Mg₂Si particles in the microstructure. Electron probe microanalysis revealed the presence of free boron on all P-Mg₂Si sites. Coupled compounds consisting of Ti, B and P were found to be associated with P-Mg₂Si which may be responsible for enhanced refinement and modification of P-Mg₂Si particles.     

Modification of Primary Mg2Si in Mg-4Si Alloys with Antimony

The refinement in size and modification in morphology for primary Mg₂Si depended significantly on Sb contents in Mg-4Si alloys. Adding Sb into melts evidently increased the nucleus numbers of primary Mg₂Si crystals. Moreover, the preferential growth along $ \left\langle { 100} \right\rangle $ directions in dendritic crystals was restricted greatly due to the Si sites being substituted by Sb in Mg₂Si lattices, resulting in modified primary Mg₂Si crystals growing to octahedral morphology surrounded by {111} planes; therefore, the modification process could be called adsorption and poisoning mechanisms.     

A Numerical Method of Macrosegregation Using a Dendritic Solidification Model,and Its Applications to Directional Solidification <Emphasis Type="Italic">via</Emphasis> the Use of Magnetic Fields

A numerical method for analyzing solidification phenomena of multicomponent alloys is presented. This method consists of macroscopic transport governing equations expressed in terms of a nonlinear multicomponent alloy model, which is coupled with the microscopic dendritic solidification model to estimate permeability. Numerical simulations were performed for channel segregation in a steel ingot and for freckles in a Ni-base IN718 remelted ingot and in Ni-10 wt pct Al directionally solidified (DS) ingots. The results show good agreement with experimental observations. The electromagnetic (EM) braking effect by static magnetic field was incorporated into the numerical method, and the anisotropic behavior of magnetic field was investigated on the DS Ni-10 wt pct Al ingots. Application of relatively low magnetic fields in the transverse to the growth direction (B _x or B _y ) resulted in formation of distorted freckles as a result of the nonuniform liquid flow induced in the transverse direction. It is shown that a considerably high magnetic field is required to suppress the distorted freckles and other freckles developed in longitudinal direction. However, there is a risk of the breakdown of DS. On the other hand, when applying the magnetic fields parallel to the growth direction (B _z ), the number of freckles inversely increased at low magnetic fields, but the freckles were eliminated by about the same level of high magnetic field as that of B _x or B _y . Because the parallel magnetic field suppresses the liquid flow vector components uniformly within the transverse plane, the nonuniform flow does not occur in the transverse directions. As a result, it suppresses the flow in the growth direction. It is envisioned that the application of the parallel magnetic field is beneficial in the commercial production of DS castings.     

Modification effect of lanthanum on primary phase Mg2Si in Mg-Si alloys

The modifying effect of La addition on primary phase Mg2Si in Mg-5Si alloys was investigated. The results showed that a proper amount of La could effectively modify the primary phase Mg2Si, Based on the present experiment, the optimal modification effect was obtained with an addition of about 0.5 wt.% La. The size of the primary phase MgzSi was considerably reduced to 25μm or less and the morphology was modified from a coarse dendritic shape to a polyhedral shape. However, when the addition of La increased to 0.8 wt.% or higher, the primary Mg2Si grew into a coarse dendritic morphology again. Moreover, it was found that some LaSi2 compounds were formed during solidification and the amount of the compounds appeared to increase gradually with increasing La content.     

SHS Metallurgy of Composite Materials Based on the Nb–Si System

Composite materials (CMs) based on niobium with functional and alloying additives (Si, Hf, Ti, Al, etc.) have prospects for industrial approval in aviation propulsion engineering. The authors previously showed that such CMs can be synthesized in an autowave mode (combustion mode) using highly exothermic mixtures of Nb₂O₅ with Al, Si, Hf, and Ti. It was found that hafnium actively participates in the reduction of Nb₂O₅, which complicates its introduction into the CM. This study is directed at investigating the possibility to synthesize Nb-based composite materials with a high Hf content using methods of centrifugal SHS metallurgy. It is shown in experimental investigations using a centrifugal installation under the effect of acceleration of 40 g that the replacement of active Hf by its less active compounds Hf–Al or Hf–Ti–Si–Al in the composition of the Nb₂O₅/Al mixtures makes it possible to transfer the combustion of the mixture from the explosion-like mode into the steady-state combustion mode. The content of Hf in the CM increases with an increase in the size of Hf–Al granules from 0–40 to 160–300 μm from 1.3 to 3.8 wt %. The introduction of Hf–Ti–Si–Al granules with a particle size from 1 to 3 mm into the initial charge makes it possible to form cast CMs based on niobium silicides with a Hf content up to 8.1 wt %. The integral composition and distribution of base and impurity elements in structure components of cast CMs, as well as their phase composition, were determined using electron microscopy and X-ray phase analysis. CMs with the maximal Hf content (8.1 wt %) contain three structural components: (1) the base, which includes Nb, Si, and Ti; (2) intergrain boundaries containing Nb, Ti, and Al; and (3) inclusions based on hafnium oxide. Three phases are revealed in the X-ray diffraction pattern of the CM, notably, solid solutions based on Nb and Nb5Si3, as well as a minor amount of Nb₃Si.     

Analysis of basic network structure of continuous casting mould powder in electromagnetic field

ABSTRACT

In the continuous casting process, the mould powder plays the role of insulator and heat insulator in the crystallizer, prevents molten steel from oxidizing, absorbs non-metallic inclusions, and controls lubrication and heat transfer between the casting billet and the mould. It is an important functional material that promotes the quality of a billet and ensures that the continuous casting process proceeds smoothly. Here in we analyse the changes in the microstructure of the protective flux from the aspect of the infrastructure of the flux slag. Additionally, using the classical molecular dynamics simulation method, the structure of the CaO–SiO₂–Al₂O₃–MgO slag system was simulated in the presence of magnetic fields of various strengths. The magnetic field was found to have the following effects on the slag structure. The participation of the basic elements Si, Al, O, etc. in bond formation is independent of magnetic field strength. The magnetic field causes changes in the peaks, coordination numbers, and peak widths of the radial distribution functions of bonds such as Si–O, Al–O, and Mg–O. The greater the magnetic field strength, the more disordered the ionic clusters are, and the greater is the decrease in slag viscosity. Although the effect of the magnetic field influences the structure of the slag, there is not much change in the way the molecules and atoms are stacked in the slag.     

Tensile and Fracture Properties of Cast and Forged Composite Synthesized by Addition of Al-Si Alloy to Magnesium

Cast Mg-Al-Si composites synthesized by addition of Al-Si alloy containing 10, 15, and 20 wt pct of Si, in molten magnesium, to generate particles of Mg₂Si by reaction between silicon and magnesium during stir casting has opened up the possibility to control the size of these particles. The microstructure of the cast composite consists of relatively dark polyhedral phase of Mg₂Si and bright phase of β-Al₁₂Mg₁₇ along the boundary between dendrites of α-Mg solid solution. After hot forging at 350 °C, the microstructure has changed to relatively smaller sizes of β-Al₁₂Mg₁₇ and Mg₂Si particles apart from larger grains surrounded by smaller grains due to dynamic recovery and recrystallization. Some of the Mg₂Si particles crack during forging. In both the cast and forged composite, the Brinell hardness increases rapidly with increasing volume fraction of Mg₂Si, but the hardness is higher in forged composites by about 100 BHN. Yield strength in cast composites improves over that of the cast alloy, but there is a marginal increase in yield strength with increasing Mg₂Si content. In forged composites, there is significant improvement in yield strength with increasing Mg₂Si particles and also over those observed in their cast counterpart. In cast composites, ultimate tensile strength (UTS) decreases with increasing Mg₂Si content possibly due to increased casting defects such as porosity and segregation, which increases with increasing Mg₂Si content and may counteract the strengthening effect of Mg₂Si content. However, in forged composite, UTS increases with increasing Mg₂Si content until 5.25 vol pct due to elimination of segregation and lowering of porosity, but at higher Mg₂Si content of 7 vol pct, UTS decreases, possibly due to extensive cracking of Mg₂Si particles. On forging, the ductility decreases in forged alloy and composites possibly due to the remaining strain and the forged microstructure. The initiation fracture toughness, J _IC , decreases drastically in cast composites from that of Mg-9 wt pct. alloy designated as MA alloy due to the presence Mg₂Si particles. Thereafter, J _IC does not appear to be very sensitive to the increasing presence of Mg₂Si particles. There is drastic reduction of J _IC on forging of the alloy, which was attributed to the remaining strain and forged microstructure, and it is further lowered in the composites because of cracking of Mg₂Si particles. The ratio of the tearing modulus to the elastic modulus in cast composites shows a lower ratio, which decreases with increasing Mg₂Si content. The ratio decreases comparatively more on forging of cast MA alloy than those observed in forged composites.     

Microstructural Aspects of Second Phases in As-cast and Homogenized 7055 Aluminum Alloy with Different Impurity Contents

The microstructural factors such as type, area fraction, morphology, distribution, and size of second phases in as-cast and homogenized 7055 aluminum alloy and the influence of impurity content variations have been investigated by using optical microscope (OM), scanning electron microscope (SEM), energy dispersive X-ray analysis (EDS), and X-ray diffraction (XRD). In as-cast microstructures, the dominant second phases of η [Mg(Al, Cu, Zn)₂] with extended solubility of Cu and Al, a small amount of impurity phases of Al₇Cu₂Fe and Al₃Fe with a little solubility of Cu and Si, and trace Mg₂Si are identified. The variations of Fe and Si contents have no significant influence on the area fraction of η phases, but the area fraction of Fe-rich phase decreases from 0.231 to 0.102 pct with Fe content decreasing from 0.080 to 0.038 wt pct. Decreasing Fe contents reduces the size parameters of Fe-rich phases and refines their morphology correspondingly. After being homogenized at 753 K (480 °C) for 24 hours, η phases are largely dissolved, but the coarse impurity phases are insoluble. Compared with as-cast microstructures, the area fraction and composition of Fe-rich phases change a little but their morphologies are slightly coarsened.     

Microstructural analysis of multilayered titanium aluminide sheets fabricated by hot rolling and heat treatment

This study is concerned with the microstructural analysis of multilayered or bulk Ti aluminide sheets fabricated by the self-propagating high-temperature synthesis (SHS) reaction using hot rolling and heat treatment. Multilayered Ti/Al sheets were prepared by stacking thin Ti and Al sheets alternately, and a good Ti/Al interfacial bonding was achieved after rolling at 500 °C. When these sheets were held at 1000 °C, spheroidal TiAl₃ phases were formed by the SHS reaction at Ti/Al interfaces and inside Al layers. Microstructural analysis on the hot-rolled, multilayered Ti/TiAl₃ sheets revealed that intermetallic phases such as TiAl₂, TiAl, and Ti₃Al were formed at Ti/TiAl₃ interfaces due to interaction between Ti and TiAl₃ and that pores formed in the TiAl₃ layer were significantly reduced during hot rolling. When multilayered Ti/Ti aluminide sheets were heat treated at 1000 °C, Ti₃Al, TiAl, and TiAl₂ were grown as Ti and TiAl₃ were consumed. As the heat treatment proceeded, TiAl grew further, eventually leading to the fabrication of multilayered sheets composed of Ti₃Al and TiAl. Bulk Ti aluminide sheets, having a lamellar structure of Ti₃Al and TiAl, instead of multilayered sheets, were also fabricated successfully by heat treatment at 1400 °C. This fabrication method of the bulk sheets had several advantages over the method by hot forging or rolling of conventional cast Ti aluminides. From these findings, an idea to fabricate multilayered or bulk Ti aluminide sheets by hot rolling and heat treatment is suggested as an economical and continuous fabrication method, and the formation and growth mechanisms of interfacial phases are elucidated in this study.