Brittle Layer Research Articles

An investigation on the effect of thermal maturity and rock composition on the mechanical behavior of carbonaceous shale formations

Abstract An accurate assessment of the geomechanical behavior of shale reservoirs is extremely significant in screening the potential intervals for hydraulic stimulation and sweet spot mapping. While most of the studies were carried out on siliciclastic shales, we here examine the mechanical behavior of a carbonaceous organic-rich shale in the Lurestan Basin, Iran, and the factors controlling them. Direct laboratory measurements at reservoir stress conditions (static method) and well-logging interpretations (dynamic approach) were employed to assess the main geomechanical properties. Besides, various experimental techniques have been employed to evaluate the dominant shale mineralogy, geochemical properties and rock fabric. It is observed that Young's modulus and Poisson's ratio, obtained from either static or dynamic approaches, are capable of reflecting rock brittleness. Conducted sensitivity analyses also reveal that abundances of organic matter, clay and carbonate minerals are the most significant factors controlling rock brittleness. An increase in the brittleness is envisioned by increasing the carbonate content and inversely by decreasing the concentrations of clay minerals and organic matter. Moreover, week or no clear relationship regarding the possible effects of thermal maturity and quartz content could be distinguished. Incorporating the distinguished controlling factors into a compositional index, a similar relative brittleness sequence with the elasticity-based approach was detected. This indicates that both independent methods are suitable for the identification of brittle layers. Inspected shale samples illustrate notably higher strengths in comparison with well-characterized organic-rich shales in the world, translated as a direct contribution of firm carbonate textures to the rock framework. Taking these textures together with the main mineral contents into account, the reservoir can be subdivided into three lithofacies including limestone, argillaceous limestone and micritic limestone. Micritic limestones show relatively higher strength and brittleness, whereas limestone and argillaceous limestone facies, in spite of high variability, reflect in average lower strength and brittle characteristics.

Ridged plains on Europa reveal a compressive past

Europa's young surface implies relatively recent resurfacing. Ridged plains, which make up >50% of Europa's surface, have not yet been fully analyzed for a potential formation mechanism. Because ridged plains dominate Europa's surface, this terrain is key to understanding how Europa has resurfaced and how the resurfacing mechanisms may have evolved through time. In this work, we create a new high-resolution topographic model and a two-layer physical analog model to investigate the formation of ridged plains. We find that the ridged plains most closely resemble the compressional physical analog experiments which generate folds. Specifically, the analog experiments with a brittle layer <1/16th the thickness of the underlying ductile-layer best explain the morphological observations of the ridged plains on Europa. Based on the scaling relationships, we find that at the time of the ridged plains formation, the brittle part of the ice shell of Europa's ice shell was ~200 m thick and the total ice-shell thickness, including both the ductile and brittle parts, was >~3000 m. Compared to the predicted current ice shell thickness, this would imply that Europa's ice-shell has thickened through the visible surface history.

Interfacial structure and formation mechanism of tungsten/steel HIP diffusion bonding joints using Ni interlayer

Tungsten and steel were successfully bonded using hot isostatic pressing (HIP) diffusion bonding with Ni interlayer. The influences of surface roughness, post-weld heat treatment (PWHT) and interlayer thickness on the properties of W/steel joint were researched, and the interfacial structure as well as the formation mechanism was investigated systematically. The results indicated that, the interfacial structure of the joint is steel/diffusion layer/reaction layer/W. The number of voids at the interface will be decreased greatly by reducing the roughness of the surfaces to be joined, which leads to the compactness of joints improving obviously. For the joints with thin (5-20μm) interlayers, after PWHT, the brittle reaction layer will further grow into W substrate and reduce the joint strength. While for those joints with thick (30-80μm) interlayers, PWHT is beneficial to increase the thickness of the helpful diffusion layer which shows the positive effect on the joint strength. A surprising result in this work is that, due to the different element concentration gradients, the structure of reaction layers is various with different interlayer thickness. With the very thin (≤20μm) interlayer, the reaction layer is a double-layer structure including W2Ni(Fe) layer and sublayer. When the thickness of the interlayer is 30μm, it is a W2Ni(Fe) single-layer structure. As the interlayer thickness increases to 50μm, the reaction layer shows a WNi and W2Ni double-layer structure. While when the interlayer thickness further increases to and above 80μm, it is a W2Ni and sublayer structure. Among the layers mentioned above, the sublayer close to W substrate is the decisive area to influence joint strength.

The Interface Microstructure and Mechanical Properties of Niobium-316L Stainless Steel Explosively Welded Composite Plate

In order to manufacture stainless steel helium vessels for the superconducting radio frequency (SRF) cavities, niobium-316L stainless steel composite plates were fabricated by explosive welding technique. The microstructure and mechanical properties of the composite plates were investigated both right after explosive welding and after annealing. The microstructure measurement results demonstrated that there was not any brittle intermetallic layer formed nor any diffusion phenomenon observed after heat treatment processes. Due to the plastic deformation and work hardening near the interface, the hardness of the composite plates was higher near the bonding interface than inside the bulk metal regions. Meanwhile, ultimate tensile strength and shear strength of the composite plate reached their maximum values when the sample was annealed at 873 K for 10 h at room temperature. Charpy impact test results at liquid helium results showed that the toughness of composite plate meets the requirements from the SRF cavities’ helium vessels fabrication.

Microstructure refinement and properties of 1.0C-1.5Cr steel in a duplex treatment combining double quenching and laser surface quenching

The 1.0C-1.5Cr steel was subjected to conventional quenching and laser surface quenching treatment. A process combing double quenching and laser surface quenching was proposed for enhancing surface hardness and obtaining finer microstructure. The cementite dissolution and grain growth behavior in the austenitizing process of single quenching, double quenching, and laser surface quenching were studied. The results indicated that compared with single quenching, mean diameter of undissolved cementite particles (UCP) was much finer in double quenching, and the final prior austenite grain size (PAGS) could be decreased by nearly 40% to about 4.5 μm. Both grain and cementite particles near the surface will coarsen after laser surface treatment. Compared with single quenching, the PAGS within hardened layer can be decreased by at least 11% through double quenching, and the mean diameter of UCP at the bottom of hardened layer can be decreased by about 20%. Compared with conventional quenching, surface hardness was enhanced by about 20% through laser surface quenching, contributing to the wear resistance. However, the hard and brittle surface layer tends to be crack source during the impact process, leading to the deterioration of final impact toughness. Under the identical laser parameters, the impact absorbed energy is similar in both single and double quenching, which is about 25% of that before laser surface quenching. The impact absorbed energy can be increased from 22J to 28J by preheating at 160 °C during the laser surface quenching.

Microstructure, mechanical properties and transformation behavior of friction stir welded Ni50.7Ti49.3 alloy

To confirm the factors of deteriorating the mechanical properties of joints and the law of transformation behavior along welds thickness, different rotation speeds were conducted for friction stir welding Ni50.7Ti49.3 alloy. Results showed that intermetallic compounds were deteriorated the mechanical properties of joints, and the joint failed before the martensitic platform appeared. W13Re7 and Ti2Ni granular shaped were distributed at the shoulder affected zone (SAZ), and this region was embrittled. Removing the brittle layer of welds surface via post-welded pickling (PWP), the tensile strength of joint at a rotation speed of 600 rpm reached 751 MPa, which reached 79.1% compared with that of the base metal (BM). After the friction stir welding (FSW), the DSC was exhibited the martensite–austenite phase transformation (B19′–B2) in the pin affected zone (PAZ) and SAZ, shown shape memory effect. Phase transformation temperatures (TTs) drifted forward to positive direction about 20 K after welding. Transformation hysteresis in SAZ decreased from 19.46 °C to 12.36 °C with increasing rotation speed from 475 rpm to 950 rpm under heat and deformation of FSW process.

Enhanced TiAl/Ti3SiC2 diffusion bonding by introducing amorphous intergranular films in Ti3SiC2 through Al doping

The Al-enriched amorphous intergranular films were firstly found and introduced in Ti3SiC2 substrates through Al doping, for enhancing the TiAl/Ti3SiC2 diffusion bonding. The existence of the Al-enriched amorphous intergranular films changed the main diffusion element from Si in the undoped TiAl/Ti3SiC2 joint to Al in the Al-doped joints. The build-ups of the interfacial compounds were γ+α2/γ/Ti5Si3/Ti3SiC2 in the undoped TiAl/Ti3SiC2 joint and were γ+α2/γ/TiAl2/TiAl3+Ti5Si3+Ti5Si4/Ti3SiC2 in the Al-doped joints. The formation of the brittle Ti5Si3 layer was inhibited through Al doping, which enhanced the shear strength of the joint.

Rheological behaviour in continental and oceanic subduction: inferences for the seismotectonics of the Aegean Region

We reconstructed several rheological transects across the Aegean Region, comparing the behaviour in collisional versus subducting settings. We interpolated closely spaced 1D strength envelopes, realized through a dedicated MATLAB script, for determining the shallow lithospheric distribution of brittle and ductile layers. We mainly used literature data and geodynamic considerations to fix the parameters for the rheological modelling and took particular care in reproducing reliable thermal models. The results of the mechanical-rheological model highlighted the following features and differences between the northern continental collision and the southern oceanic subduction settings: i) a slightly shallower brittle-ductile transition (BDT) in the western sectors of the northern transects (~30-33 km) with respect to the southern ones (~40 km); ii) on the contrary, in the central-eastern sectors of the investigated area, corresponding to an extensional tectonic regime, the northern transects have a relatively deeper BDT (about 20-25 km) compared with the southern ones (about 15 km); iii) the occurrence of a thick, deeper brittle layer below the shallowest BDT, in the centraleastern sectors of the northern transects. We suggest that such regional differences are mainly related and attributable to the surface heat flow distribution (which directly affects the geothermal gradient) and to the tectonic and geodynamic context. The results of the rheological modelling in terms of depth extent of the brittle layer(s) have been compared with the depth distribution of available relocated seismicity, showing good agreement with the rheological layering proposed here. Finally, the depth of the shallowest BDT along the transects has been adopted as a constraint for the seismogenic layer thickness. Such information has been used to improve the seismotectonic characterization of selected crustal seismogenic sources crossing the transects, by estimating their maximum potential magnitudes on the basis of their geometrical features and consistency with the rheological layering.

Surface Fracture Prevention in Paperboard Press Forming with Advanced Force Control

Press forming is a three-dimensional forming process used for industrial converting of large quantities of fibre-based composite materials such as barrier coated paperboard. The technology enables the production of plate and tray packages of such high quality that it is possible to lid seal them to create a gas-tight package. The method is primarily based on the controlled folding and compression of materials using high forming forces and elevated tool temperatures.The corner of the container is folded utilizing creases and a certain amount of force is needed to achieve the desired result. Sliding of the package blank is restrained with blank holding force which defines the overall forming force. The magnitude of blank holding force is determined by the shape and dimensions of the package and the properties of the material to be moulded.In some cases, the force optimized to produce high-quality packages will cause fractures, which are only on the surface layer of the paperboard, at corners of the tray. The packaging is still fully functional, but the visual disadvantage makes it look defective. The phenomenon is accentuated in converting of printed paperboard, where the potentially brittle surface layer breaks more easily and the colour difference makes the fractures eye-catching.This study investigated how by adjusting the blank holding force, paperboard surface layer breakage can be prevented during processing. Various ramps were programmed to control the forming cycle, which changed the magnitude of the force during the pressing stroke. The results show that there is no need to compromise the quality of the package as long as the average magnitude of the blank holding force is maintained. If the strength properties of the material to be formed are not sufficient to apply a constant blank holding force, by reducing the force slightly at certain points in the process cycle, material damage can be reduced or prevented completely.

Investigation on microstructure and mechanical properties of Al/Cu butt joints by CMT method in asymmetrical V-groove configuration

It is a challenge work for joining of Al to Cu by conventional fusion welding method. This study investigates butt joining of 6061 Al alloy to pure copper using cold metal transfer (CMT) process in asymmetrical V-groove configuration. The microstructure and mechanical properties of Al/Cu butt joints are revealed. The microstructure in the fusion zone mainly consists of α (Al) and Al2Cu phase accompanied with Si phase. The two-layer intermetallic compound (IMC) layers are exhibited at the Al/Cu interface. The first IMC layer near the copper is a thin layer in thickness of less than 5 μm. The second IMC layer is in the irregular non-linear and zigzag shape with some particles dispersed at the boundaries. XRD analysis shows that the IMCs in the joints mainly contain Al2Cu, AlCu, Al3Cu4 and Al4Cu9 phase. The ultimate tensile strength (UTS) of the joints could reach 108 MPa. The fracture paths of the joints are along the Al/Cu interface. The pores and IMCs are main factors to determine the strength of the joints. Since the pores are at the Al/Cu interface, the UTS of the joint is lowered at low wire feed rate. The joints break along the Al/Cu interface due to the brittle IMC layer at high wire feed rate. It can be achieved Al/Cu butt joints with sufficient strength in asymmetrical V-groove configuration.

Effects of ERNiCr-3 butter layer on the microstructure and mechanical properties of API 5L X65/AISI304 dissimilar joint

This paper investigates the effects of ERNiCr-3 butter layer on the microstructure and mechanical properties of API 5 L X65/AISI 304 dissimilar joint, welded by gas tungsten arc welding (GTAW). The butter layer is applied to minimize carbon diffusion from the base metal to the welding pool and to eliminate the risk of the formation of a hard martensitic layer at the fusion line. The microstructures of buttered and non-buttered specimens were studied using the optical microscope, scanning electron microscope (SEM), electron backscattering diffraction (EBSD), X-Ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). Mechanical properties of the joints were also evaluated using standard and sub-sized tensile and impact tests. Hardness profilometry was also conducted across the weldments. Results showed that the application of the butter layer results in the elimination of a rather large brittle martensitic layer from the base metal at the API side. Also, it appears that the weld zone in the buttered sample hardly has any δ-ferrite, which has to do with a high nickel content of the butter layer. Butter layer overall decreases the tensile strength and increases the elongation/ductility of the joints. More importantly, the butter layer essentially acts as a barrier layer between the ferritic side of the weldment and the weld pool, and this, in turn, eliminates two hardness peaks at both sides of the welding pool. The correlations between microstructure and mechanical properties are comprehensively investigated and discussed.

Understanding and treatment of squat defects in a railway network

A comprehensive investigation of the Sydney Trains railway network has been carried out to control and minimize rail degradation, especially squat defects. Squat occurrence was analysed with respect to the parameters of traffic operation and track geometry. Detailed metallurgical examination of the ex-service rails revealed a possible connection between brittle White Etching Layers (WELs) and the occurrence of squats in the running band of the rail. Initiation of squats was found to be associated with the progression of surface cracks in the WELs. Furthermore, two distinguishable types of WELs were found, based on different track operational conditions. These are described as Thermally Produced WEL (TP-WEL) which was found in heavy braking regions, and Severe Deformation WEL (SD-WEL) which was found in track regions under steady traffic speeds. In addition to the explanations based on thermal phase transformation and severe plastic deformation, the arcing phenomenon associated with electrical leakage at the wheel/rail interface was considered an alternative formation mechanism of WELs observed on rails. A revised rail grinding strategy was proposed by considering the formation of WELs and addressing it through more regular, relatively shallow grinding to effectively control squat defects.

Oxide scale on stainless steels and its effect on sticking during hot-rolling

The failure of oxide scales on ferritic stainless steels (STSs) has been known to cause an unexpected and severe sticking problem during the hot-rolling process. The oxide scale fragments formed during hot-rolling are stuck on the surfaces of the working roll, deteriorating the surfaces of both the roller and the rolled materials. In this study, we investigate the effects of the compositions and microstructures of thermally grown oxide scales on the degree of sticking during hot-rolling in three different kinds of commercial ferritic STSs and one austenitic STS. The STS samples are oxidized at around 1280 °C for 2 h, and the oxide scales formed on the STSs are identified by X-ray diffraction (XRD). Additionally, the cross-sectional microstructure and chemical compositions of the oxide scales on the STSs are examined by electron probe microanalysis (EPMA) and scanning electron microscopy (SEM), respectively. The oxide scales adjacent to the interfaces with the bulk STS are analyzed by high-resolution transmission electron microscopy (HR-TEM). The Gleeble test, which is a high-temperature (1250 °C) tensile test, is conducted to analyze the effects of the stress induced in the oxide scales during hot-rolling on the fracture of the scales. According to the microstructural analysis and mechanical test results, a brittle Cr2O3 layer, where cracks are easily formed and propagate through the scale thickness under the stress induced by hot-rolling, is formed along the interfaces of STSs with high Cr contents. This effect increases the probability of sticking failure in high-Cr STSs. In contrast, scales with a composite-like structure of Fe- and Cr-oxides are formed on the surface of STSs containing low and medium levels of Cr. According to the Gleeble test results, the composite-like oxide scales show higher mechanical resistance to tensile stress than the Cr2O3 layers in the high-Cr STSs. In addition, our microstructural analysis results reveal that FexNiy intermetallic compounds are observed as a form of a composite-like structure inside the oxide scales in the austenitic STS and that this structure also delays crack propagation through the oxide scales and reduces the degree of sticking.

Comparative study on crack resistance of TiAlN monolithic and Ti/TiAlN multilayer coatings

TiAlN monolithic and Ti/TiAlN multilayer coatings were fabricated on Ti–6Al–4V substrates by a self-designed multisource cathodic arc ion deposition system. The mechanical properties and crack evolution of the coatings were focused under scratch tests with different constant loads. Results showed that the multilayer coating exhibited a higher combination of plasticity, crack resistance and load capacity comparing to those of the monolithic coating. Namely, radical cracks, chippings, and lateral cracks were observed in the monolithic coating after scratch test, whereas only radical cracks occurred in the multilayer coating. The surface and cross-sectional morphology of the scratch tracks revealed that bending and shear stress were responsible for the failure of the two coatings. In particular, the ductile Ti layers within the multilayer coatings could coordinate the deformation and enhance the adhesion between the substrate and the brittle TiAlN layers, which further hindered the propagation of cracks, resulting in a higher crack resistance.

A novel titanium enhanced plasma nitriding for 42CrMo steel

Titanium enhanced plasma nitriding was primarily developed for 42CrMo steel, excellent characteristics of nitriding layer with thinner brittle compound layer, thicker effective hardening layer and higher hardness was obtained by the novel titanium enhanced plasma nitriding. Under the same nitriding parameters of 540 °C × 4 h, the thickness of effective hardening layer was increased from 225 μm to 380 μm; the thickness of brittle compound layer was decreased from 19 μm to 10 μm. More importantly, the surface hardness was significantly increased from 703HV0.05 to 895HV0.05 due to the formation of TiN nitrides. The research can provide new insights into plasma nitriding technology.

The use of low cost, abundant, homopolymers for engineering degradable polymer blends: Compatibilization of poly(lactic acid)/styrenics using poly(methyl methacrylate)

Using known parameters for the surface and interfacial tension, the work of adhesion of PMMA with PLA and styrenic polymers has been calculated. The results indicated that PMMA, an abundant and economical homopolymer, could serve as an effective compatibilizer, rivaling complex and costly block copolymers for PLA/styrenic blends. Blends of PLA with either SAN or ABS were produced with added 1%–10% PMMA. Tensile and impact toughness data show that the blends display properties comparable to those of PP with only 4% added PMMA. Deuterated-secondary ion mass spectrometry (DSIMS) performed with deuterated PMMA indicated that this corresponded to the formation of an interfacial layer approximately 2Rg thick, as the optimal thickness for integrating two polymers, without the formation of a third brittle layer. Blends with ABS showed an increase of nearly 300% in impact toughness compared to that for polymer containing no PMMA, while blends with SAN formed ideal extruded filaments, which produced 3-D printed structures at least 58% stronger and more ductile than molded PS.

Formation of Alpha-Case Layer During Investment Casting of Pure Ti and Ti-6Al-4V Using Comparative XRD and EXAFS Investigation

In titanium casting, a reaction byproduct known as alpha-case is a hard and brittle phase layer that exists on the surface of cast objects. This reaction layer may be detrimental to the mechanical properties of cast objects and may complicate the finishing processes. To investigate the formation of the alpha-case layer during the casting of commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy, both metal ingots were cast in spinel-based investments in a controlled environment. The cast samples were metallographically prepared and analyzed for the thicknesses of alpha-case layer depth and the metal matrix. The samples were characterized using light microscopy, Vickers microhardness testing, X-ray diffractometry, and extended X-ray absorption fine structure spectrometry. The alpha-case layer on the CP-Ti cast sample was thicker than that of the Ti-6Al-4V cast sample due to the ability of the α-titanium matrix to uptake oxygen faster, which in turn is attributed to the higher diffusion coefficient of the α-titanium phase. A metastable Ti3O phase was observed as an intermediate reaction product which could be transformed into the alpha-case layer and the α-titanium phase.

The influence of flame and furnace soldering method on the stress corrosion, fatigue resistance and fracture toughness of soldered bar attachment systems for implant overdentures

ABSTRACTThe purpose of the study was to investigate the influence of flame and furnace soldering methods on the stress corrosion, fatigue resistance and fracture toughness of a ‘Dolder’ bar soldered to a non-oxidising gold cylinder using a gold solder. Two bars were soldered to opposite sides of a cylinder using the two techniques. Fatigue cycling one side of the bars was undertaken, with one group in a wet corrosive environment and the other in air. Force displacement load-unload curves was established to 100 N as a base line, thereafter, every 1000 cycles to 100 N load for 10,000 cycles. The system compliance and energy loss (mJ), was calculated. The critical stress intensity factor, K1c, of the solder/cylinder interface was established using a single-edge-notched-beam test. Mode of failure was evaluated using SEM. No corrosion was observed in the wet environment. Both soldering methods produced a thin brittle diffusion layer within the surface of the cylinder. The K1c of this layer was similar to that of a brittle ceramic. No embrittling reaction occurred at the solder/bar junction. This interfacial reaction has clinical relevance for soldered bar attachment systems using non-oxidising cylinders.

Fault spacing in continental strike-slip shear zones

Strike-slip shear zones with sub-parallel arrays of evenly-spaced faults are widely observed in nature, but the controls on the spacing between major faults are unclear. We analyze a 2-D model and develop a scaling law relating the fault spacing to structural and rheological parameters in the continental crust. We find that fault spacing positively correlates with brittle-layer thickness, viscous lower crust thickness, and strength contrast between active faults and surrounding intact blocks; and is inversely correlative with lower crust viscosity. This is corroborated for either a zero-shear traction (decoupled) or a prescribed velocity (coupled) basal boundary condition in the 2-D analytical solution. The zero-shear traction boundary condition represents low viscosities in the lowermost crust or the topmost mantle that may decouple deformations from mantle flow. The prescribed velocity boundary condition emphasizes basal drag tractional forces imparted on the lower crust by a strong mantle. For a viscous layer that is thicker than half of its average fault spacing, models with either of the boundary conditions produce the same results. Otherwise, a thinner, viscous layer with a linear-velocity condition tends to produce smaller fault spacings than a no-shear model, all else being equal. These theoretical models are comparted to data from shear zones in California, the Marlborough Fault Zone in New Zealand and central Tibet. Modeling indicates that the effective viscosity of the viscous layer underlying the brittle layer in all of the selected areas is 2×1020 to 4×1021 Pa⋅s. The subducted oceanic plate attached to the lower crust of the eastern Marlborough Fault Zone also appears to influence fault spacing in the overriding plate.

Synthesis and Fracture Characteristics of TiB2-TiAl Composites with a Unique Microlaminated Architecture

Microstructural evolution of as-rolled (TiB2/Al)-Ti laminates in the process of multistep heat treatments and microstructural characteristics of the resulting TiB2-TiAl composites were investigated in detail by scanning electron microscope (SEM) and transmission electron microscope. The desired TiB2-TiAl composites exhibited a unique microlaminated structure consisting of alternating fully lamellar α2-Ti3Al/γ-TiAl layers and TiB2-rich layers. Moreover, the formation mechanism of the microlaminated structure was elucidated. It is noteworthy that the TiB2-TiAl composites showed improved high-temperature tensile properties and room-temperature fracture toughness due to the strengthening effect of TiB2 particles and the structure effect of the unique microlaminated microstructure. In addition, the fracture behavior of the microlaminated TiB2-TiAl composites during the dynamic tensile was characterized by combining use of the three-dimensional X-ray microscope (3D-XRM) and SEM. The results indicated that pores and cracks preferred to initiate in the brittle TiB2-rich layer and showed a typical layered distribution, and then expanded into a nearby fully lamellar α2/γ layer and kept propagating through the entire α2/γ layer into another TiB2-rich layer, repeatedly, and finally the main crack propagated through all the fully lamellar α2/γ layers and TiB2-rich layers, eventually resulting in failure. Thus, the fracture mechanism of the innovative microlaminated TiB2-TiAl composites was proposed.