Andrii Kostryzhev

University of Queensland | UQ · Centre for Microscopy and Microanalysis

The present study investigates the relative effect of B and N concentrations and the aus-tenitization temperature on the microstructure and mechanical properties (tensile and Charpy impact) of modified 9Cr-1Mo (P91) steels. Initially, a B-free P91 steel (with 500 ppm N) and four different B-containing steels (25-100 ppm) with varying N concentratio...

Monel alloys containing 63Ni–30Cu (wt%) are often used in applications requiring simultaneously high strength and corrosion resistance. Additions of Ti, Al and C to Monel K500 lead to formation of TiC, Ni3Al and Ni3Ti particles, which provide precipitation strengthening effect following heat treatment. The traditional heat treatment schedule includ...

Currently, ceramics are widely used in various industry branches, especially in energy, chemistry, and aerospace, as well as in medicine. Yttria-stabilized zirconia (YSZ) having unique electrical, thermal, and mechanical properties is one of the most popular ceramics for such applications. In this study, the influence of sintering temperature and y...

Yttria-stabilized zirconia (YSZ) is well-known as a material with perfect mechanical, thermal, and electrical properties. It is used for manufacturing various high-temperature components for aerospace and energy generation, as well as wear- and corrosion-resistant devices in medicine. This work investigated the effect of a Y2O3 addition to ZrO2 on...

High yield strength (710–862 MPa) ferritic microalloyed steels are developed through the combined contribution of Nb, Mo, V, and Cr microalloying and controlled thermomechanical treatment. Microstructures and mechanical properties are characterized using advanced microscopy techniques and uniaxial tensile testing. NbV carbonitrides with/without Mo...

Monel alloys containing 63Ni-30Cu-2.0Mn-2.0Fe-AlTiC (wt. %) are often used for manufacturing of machine parts in marine, chemical, and oil extraction industries. Despite excellent corrosion resistance and mechanical properties, Monel components may fail via wear, which is enhanced in corrosive environment. Heavy components working under high loads...

Recently developed Ti-alloyed martensitic steels are believed to exhibit higher wear resistance than traditionally quenched and tempered medium carbon steels. However, their properties may deteriorate during thermal cutting and welding as a result of microstructure tempering. This would present significant challenges for the metal fabrication indus...

The mechanical properties of contemporary engineering alloys are approaching their natural limits [...]

Laser alloying is an effective method to form functional surface layers (coatings) on metallic materials, particularly on stainless steels. Unique phase balance, dislocation substructure, and a possibility to obtain gradient microstructures after laser alloying slow down the surface degradation and increase the wear resistance. In this work, the op...

Novel steel microalloyed with 0.73 (Cr + V + Nb) has been subjected to thermomechanical processing (TMP) with varying parameters to simultaneously maximise the steel strength and ductility. Optical and electron microscopy studies coupled with uniaxial tensile testing were carried out to analyse the processing-microstructure-properties relationship....

Nickel-Copper (Ni-Cu) alloys exhibit simultaneously high strength and toughness, excellent corrosion resistance, and may show good wear resistance. Therefore, they are widely used in the chemical, oil, and marine industries for manufacturing of various components of equipment, such as: drill collars, pumps, valves, impellers, fixtures, pipes, and,...

The traditional approach to improving the abrasion wear resistance of martensitic steels is to increase their hardness via high carbon levels. However: (i) a higher hardness is usually accompanied by a lower toughness, negatively affecting the impact wear resistance, and (ii) increased carbon concentrations reduce weldability and complicate thermal...

Instead of conventional steel making and continuous casting followed by hot and cold rolling, strip casting technology modified with the addition of a continuous annealing stage (namely, modified strip casting) is a promising short-route for producing ferrite-martensite dual-phase (DP) and multi-phase transformation-induced plasticity (TRIP) steels...

Two Ni–Cu alloys with various contents of Mn, Ti, Al and C were deposited in a shape of single-bead multi layered walls using wire arc additive manufacturing technology. To modify solute atom concentrations and particle number density values, the as-welded alloys were subjected to annealing at 1100 °C and age-hardening heat treatment in the 610-480...

The acoustic emission (AE) monitoring technique is widely used in mechanical and materials research for detection of plastic deformation, fracture initiation and crack growth. However, the quantitative dependences of the AE signal parameters on material fracture parametersare not completely understood. This paper presents recent research results on...

Two Ni–Cu alloys, Monel K500 and FM60, with various contents of Ti, Mn, Al, Fe and C were deposited in the form of plates on a metal base plate using wire arc additive manufacturing technology. Three deposition speeds have been applied: 300, 400 and 500 mm/min. To modify the as-welded microstructure and properties, the deposited walls/plates have b...

Three novel low carbon microalloyed steels with various additions of Mo, Nb and V were investigated after thermomechanical processing simulations designed to obtain ferrite-bainite microstructure. With the increase in microalloying element additions from the High V- to NbV- to MoNbV-microalloyed steel, the high temperature flow stresses increased....

Two Ni-Cu alloys (Monel K500 and FM 60) having various Mn, Fe, Al, Ti and C contents were deposited on a Monel K500 plate at three different speeds using wire arc additive manufacturing technique. Microstructure characterisation, in particular a detailed study of precipitates, was carried out using optical and scanning electron microscopy. Mechanic...

Global economy requires steel with further increasing mechanical properties and simultaneously decreasing price. In mass manufacturing three major methods can be used to increase strength: (i) increase microalloying element additions (increases cost), (ii) decrease deformation temperature and (iii) increase cooling rate after high temperature proce...

Steel product markets require the rolled stock with further increasing mechanical properties and simultaneously decreasing price. The steel cost can be reduced via decreasing the microalloying elements contents, although this decrease may undermine the mechanical properties. Multi-element microalloying with minor additions is the route to optimise...

High temperature confocal microscopy (using cooling rates of 1 and 20 °C s⁻¹) has been used in conjunction with segregation modeling (for cooling rates of 0.1–100 °C s⁻¹) to understand the implications that high cooling rates, representative of that seen for belt casting, has on compositional inhomogeneity and precipitation in high strength low all...

Knowledge of carbon content in retained austenite (RA) with different neighbouring phases is essential to understand the chemical stability of RA, which is useful for microstructure tuning of transformation-induced plasticity (TRIP) steels. The present study investigates different morphologies and chemical compositions of RA by correlating electron...

Thermo-mechanical processing of a strip cast dual phase (DP) steel was carried out using a Gleeble thermo-mechanical simulator. The effect of deformation temperatures in the range from 1050 to 700 °C on the microstructure evolution was investigated using optical, scanning and transmission electron microscopy along with electron backscattering diffr...

In this paper we introduce the AC²WD-technology, which stands for Austenite Conditioning – Accelerated Cooling – Warm Deformation. This technology was tested in laboratory conditions using a Gleeble thermomechanical simulator. Two microalloyed steels processed via this technology have shown a superior combination of mechanical properties, compared...

In steels the dependence of ambient temperature microstructure and mechanical properties on solidification rate is not well reported. In this work we investigate the microstructure and hardness evolution for a low C low Mn NbTi-microalloyed steel solidified in the cooling rate range of 1–50 Cs⁻¹. The maximum strength was obtained at the intermediat...

Instead of hot rolling and cold rolling followed by annealing, strip casting is a more economic and environmentally friendly way to produce transformation-induced plasticity (TRIP) steels. According to industrial practice of strip casting, rapid cooling in this work was achieved using a dip tester, and a Gleeble 3500 thermo-mechanical simulator was...

Application of cast steels instead of hot forged or rolled ones will significantly decrease manufacturing costs and the final product price. However, low levels of mechanical properties in cast steels, especially ductility, can slow down the substitution of forged and rolled steels with the cast. In the present work, the authors study the effect of...

Conventional transformation induced plasticity (TRIP) steel (0.17C-1.52Si-1.61Mn-0.03Al, wt%) was produced via strip casting technology simulated in the laboratory. Effects of holding temperature, holding time and cooling rate on ferrite formation were studied via analysis of the continuous cooling transformation diagram obtained here. A typical mi...

Transmission Kikuchi Diffraction orientation mapping correlated with transmission microscopy observations was applied to a multi-phase TRIP-TWIP steel subjected to 66% cold-rolling and 625°C annealing. The cold-rolled microstructure and micro-texture suggests the possibility of variant selection in the ɛ and α′ phases at the local map scale. Upon a...

In this original work, the dislocation structure and NbC precipitation were investigated in three Ni-based alloys (70Ni–Fe–0.331Nb–0.040C, 70Ni–Fe–0.851Nb–0.114C and 70Ni–Fe–1.420Nb–0.157C, wt%) thermomechanically processed in the temperature range of 1250–1075 °C. The dislocation structure inhomogeneity (dislocation networks and cell walls), which...

Conventional dual phase (DP) steel (0.08C–0.81Si–1.47Mn–0.03Al wt.%) was manufactured using simulated strip casting schedule in laboratory. The average grain size of prior austenite was 117±44 μm. The continuous cooling transformation diagram was obtained. The microstructures having polygonal ferrite in the range of 40–90%, martensite with small am...

This research investigates the effect of thermomechanical processing (TMP) parameters (temperature and strain rate) and the addition of Nb and C on the dynamic recrystallisation (DRX) of austenite and on deformation activation energy using Ni–30Fe–Nb–C and Ni–30Fe–C model alloys. Plane strain compression tests were carried out in a Gleeble TMP simu...

This paper presents an investigation of the fracture behavior of X70 pipeline steel using the acoustic emission (AE) monitoring technique. The AE monitoring technique is widely used in mechanical and materials research for detection of plastic deformation, fracture initiation and crack growth. However, quantitative dependences of the AE parameters...

The effect of deformation temperature on microstructure and mechanical properties was investigated for thermomechanically processed NbTi-microalloyed steel with ferrite-pearlite microstructure. With a decrease in the finish deformation temperature at 1348 K to 1098 K (1075 °C to 825 °C) temperature range, the ambient temperature yield stress did no...

The Acoustic Emission (AE) monitoring technique is widely used in mechanical and material research for detection of plastic deformation, fracture initiation and crack growth. However, the influence of AE features (such as signal amplitude, frequency, rise time and duration) on the fracture parameters (such as brittle or ductile mode of propagation...

The laboratory simulation of strip casting of dual phase (DP) and transformation-induced plasticity (TRIP) steels was carried out using heat treatments of dip-cast samples in a dilatometer. The microstructure of DP steel (0.08C-0.81Si-1.47Mn-0.03Al wt. %) consisted of ~80 % ferrite and remaining martensite with little of bainite, whereas the micros...

The unavoidable phase transformation upon cooling makes a direct observation of austenite microstructure impossible. One of the methods to investigate the high temperature condition of austenite is to use a model alloy, which would not transform to martensite on quenching. In the present work the recrystallisation and grain growth of austenite duri...

A base low Si, high-Al transformation-induced plasticity (TRIP) steel and one with 0.03Nb and 0.02Ti (wt%) additions were subjected to thermo-mechanical processing (TMP) and galvanising simulations. The microstructure and mechanical properties were analysed using a combination of optical and electron microscopy, X-ray diffraction and tensile testin...

The effect of thermomechanical processing conditions on Nb clustering and precipitation in both austenite and ferrite in a Nb-Ti microalloyed steel was studied using electron microscopy and atom probe tomography. A decrease in the deformation temperature increased the Nb-rich precipitation in austenite and decreased the extent of precipitation in f...

Conventional dual phase (DP) steel (0.08C-0.81Si-1.47Mn-0.03Al, wt. %) was manufactured by the laboratory simulation of strip casting. The effect of holding temperature and time on microstructure evolution was studied using a quench-deformation dilatometer. Microstructures were observed using optical and scanning electron microscopy. The results sh...

The effect of deformation temperature on Nb solute clustering, precipitation and the kinetics of austenite recrystallisation were studied in a steel containing 0.081C–0.021Ti–0.064 Nb (wt%). Thermo-mechanical processing was carried out using a Gleeble 3500 simulator. The austenite microstructure was studied using a combination of optical microscopy...

An investigation into influence of the austenitising temperature and the austenite deformation temperature on Nb precipitation and recrystallisation kinetics was carried out for a steel containing 0.081C–0.021Ti–0.064Nb (wt. %). The austenite grain structure was correlated to the dispersive properties of Nb atom clustering and precipitation. Irresp...

Increased traffic speeds and axle loads on modern railways enhance rail track degradation. To eliminate track failure due to rail defects, a condition monitoring system requires methods for the early detection of defects which grow in service. Acoustic emission (AE) monitoring is the only nondestructive technique which might be applied online to st...

Acoustic emission (AE) monitoring has been used to detect split formation during room temperature low blow Charpy impact testing of high strength thick strip steels. The AE signal analysis identified separate signals originating from hammer impact, plastic deformation (verified using Charpy impact testing on mild steel with no splits) and split ini...

The Bauschinger effect (a reduced yield stress at the start of reverse deformation following forward prestrain) is an important factor of strength development for cold metal forming technology. In steels, the magnitude of the Bauschinger effect depends on composition, through the presence of microalloy precipitates, and prior processing, through th...

Alternating current field measurement (ACFM) sensors can be used to detect surface breaking defects in metal components. In rails rolling contact fatigue (RCF) cracks form due to the wheel–rail contact stresses. These cracks are surface breaking and can have complex shapes. A COMSOL model has been developed for a commercial ACFM system and RCF crac...

High strength low alloy strip steels (HSLA), with a yield strength of ~700 MPa, have shown broad transition regions in Charpy testing, with splits being seen on the fracture surface in the upper transition region. Strip steel, with a polygonal ferrite microstructure and having been processed to two strip thicknesses (10.0 mm and 16.8 mm) have been...

Rolling contact fatigue (RCF) cracks in the rail head progressively grow due to in-service loading. Early detection and sizing of RCF cracks allows more efficient mediation treatment such as grinding. In this paper the capability of an Alternating Current Field Measurement (ACFM) technique to detect and size light to moderate RCF cracks, both at hi...

The Bauschinger effect (yield stress decreasing at the start of reverse deformation after forward prestrain) is an important factor in strength development for cold metal forming technology. In steels, the magnitude of the Bauschinger effect depends on composition, through the presence of microalloy precipitates, and prior processing, through the s...

Mechanical properties of large diameter welded steel pipes depend on the thermomechanically controlled rolled (TMCR) plate microstructure and UOE pipe-forming cold deformation sequence. Strength from plate to pipe may increase (work-hardening) or decrease (the Bauschinger effect). Bauschinger effect parameters depend on steel composition and plate...

The UOE process is used for cold forming of large diameter steel line-pipes. Pipe strength has been found to increase (work hardening) or decrease (Bauschinger effect) after the UOE process compared to the plate depending on the steel grade, plate and pipe processing history. The steel chemistry, through the presence of microalloy precipitates, and...

Mechanical properties of large diameter welded steel pipes depend on the TMCR-plate microstructure and UOE pipe-forming cold deformation sequence. Strength from plate to pipe may increase (work-hardening) or decrease (the Bauschinger effect). Bauschinger effect parameters depend on steel composition and plate processing history. The present study i...

Large diameter steel line pipes are generally produced by cold deforming hot rolled or thermomechanically controlled rolled (TMCR) plate by the three-stage 'UOE' process. Pipe strength has been found to increase or decrease relative to the plate, depending on the steel grade and plate processing history. The strength increase is due to work hardeni...

See abstract in the attached file

At present the bearing thick-walled tubes of < 90 mm in diameter are produced by rolling in the mills of cold periodical rolling (pilger mills) or by drawing. These tubes are characterised by a narrow gradation in geometry, especially in the small diameter range. In particular, the nearest tube sizes in outside diameter may vary within 1-2 mm. Such...