Mechanical Thermal Treatment Research Articles

Effect of Mo addition on the microstructural evolution and mechanical properties of Fe–Ni–Cr–Mn–Al–Ti high entropy alloys

High-strength alloys are in urgent demand for engineering applications. Inducing multiple strengthening phases in a ductile matrix by microalloying is an effective alloy-strengthening strategy, especially the simultaneous formation of geometrically close-packed (GCP) phases and topologically close-packed (TCP) precipitation in high entropy alloys (HEAs). In this study, the microstructural evolution and mechanical properties of a series of (FeNi)67Cr15Mn10-xAl4Ti4Mox HEAs with x values of 1, 2, 3, 4, and 5 were analyzed in detail, with the substitution of Mn by Mo. This substitution does not change the L12 phase forming elements (Ni, Al and Ti) in the alloy, and enhance the σ phase precipitation, which meantime does not modify the oxidation resistance in thermal mechanical treatment. After aging at a temperature of 1023 K for 5 h, the matrix of the HEAs still maintains a face-cubic-centered structure. However, as Mn is replaced by Mo, hard σ precipitates are introduced into the matrix and the grains are significantly refined when x < 5. Therefore, the yield strength monotonically increases with increasing x. However, the formation of the hard σ precipitates also hinders the sustainability of the work hardening process, and thereby decreases the plasticity of the HEAs. Hence, the elongation at break monotonically decreases with increasing x. However, the high density of σ phase precipitates obtained at x = 5 prematurely terminates the work hardening process. Therefore, the highest ultimate tensile stress is obtained at x = 4, rather than x = 5. This also changes the fracture morphology from a coarse grain morphology for x < 5 to a typical brittle fracture at x = 5. Accordingly, (FeNi)67Cr15Mn6Al4Ti4Mo4 obtains the optimal mechanical properties overall.

Quantitative analysis of hetero-deformation induced strengthening in heterogeneous grain structure

A single-phase bimodal grain structure is considered to develop a physical model to quantify hetero-deformation induced (HDI) strengthening at the yield point, which cannot be simply predicted by the conventional rule-of-mixtures using the Hall-Petch equation. Based on the classic theory of single-ended continuum dislocation pileup, the modified model parameterizes the effective width of hetero-boundary affected region (Hbar) as well as the contribution of HDI stress to 0.2% proof stress. To further verify the model equations, the equimolar CoCrNi medium entropy alloy was selected as a model material. The heterogeneous grain structure (HGS) was introduced via thermal-mechanical treatment, and statistical analysis of microstructure was performed by means of electron backscattered diffraction. By substituting derived parameters, our model can predict theoretical values of the yield stress and the width of Hbar, both comparable to the experimental value from tensile testing, as well as previous experimental observations. The reasonable agreements can not only prove the validity of the current modified model, but also bring out physical explanations for the extra strengthening in heterostructured materials.

Investigation on recrystallization behavior of Ti-47Al-1.5Re-X (Cr, Mn, V, Nb) alloy during hot deformation

The recrystallization behaviors of TiAl alloy play major roles in the microstructure control during the thermal–mechanical treatment, affected intensively by alloy composition. Hence, the effect of alloy elements (Cr, Mn, V, Nb) on the recrystallization of Ti-47Al-1.5Re-X alloy was investigated by thermal simulation compression. Cr and V could increase the DRX critical strain. Mn and Nb could broaden the lamellar spacing, and promote the onset of dynamic recrystallization (DRX). Meanwhile, the DRX kinetics was dramatically slowed by adding alloy elements, while Mn caused the least negative effect. Additionally, Cr, Mn, and V were demonstrated to expedite the SRX/MDRX kinetics by a qualitative analysis method, while Nb resulted in the opposite effect. Eventually, the comprehensive deformation performance was discussed, summarizing that Ti-47Al-1.5Re-2Mn alloy is the optimal deformed TiAl alloy.

Chemical-element-distribution-mediated deformation partitioning and its control mechanical behavior in high-entropy alloys

• Effect of chemical heterogeneities on plasticity and strength is studied using atomic simulations in high-entropy alloys. • Elemental anisotropy/difference factor is proposed, and then used to evaluate the short range order and predict the HEA properties. • Elemental anisotropy factor for optimal high performance is accurately estimated by machine learning. • By a machine learning approach coupled with MD simulations, elemental anisotropy ranges from 2.9 to 3. The chemical element distributions always strongly affect the deformation mechanisms and mechanical properties of alloying materials. However, the detailed atomic origin still remains unknown in high-entropy alloys (HEAs) with a stable random solid solution. Here, considering the effect of elemental fluctuation distribution, the deformation behavior and mechanical response of the widely-studied equimolar random CoCrFeMnNi HEA are investigated by atomic simulations combined with machine learning and micro-pillar compression experiments. The elemental anisotropy factor is proposed, and then used to evaluate the chemical element distribution. The experimental and simulation results show that the local variations of chemical compositions exist and play a critical role in the deformation partitioning and mechanical properties. The high strength and good plasticity of HEAs are obtained via tuning the chemical element distributions, and the optimal elemental anisotropy factor ranges from 2.9 to 3 using machine learning. This trend can be attributed to the cooperative mechanisms depending on the local variational composition: massive partial dislocation multiplication at an initial stage of plastic deformation, and the inhibition of localized shear banding via the nucleation of deformation twinning at a later stage. Using the new insights gained here, it would be possible to create new metallic alloys with superior properties through thermal-mechanical treatment to tailoring the chemical element distribution.

Effect of physical aging and cyclic loading on power-law creep of high-entropy metallic glass

The power-law relationship between creep rate decay and time is one of the intrinsic characteristics of metallic glasses. In the current work, a La30Ce30Ni10Al20Co10 high-entropy metallic glass was selected as the model alloy to test the influences of physical aging and cyclic loading on the power-law creep mechanism, which was probed by the dynamic mechanical analysis in terms of the stochastic activation, and contiguous interplay and permeation of shear transformation zones. It is demonstrated that a notable discrepancy appears between thermal treatment and mechanical treatment on the power-law creep mechanism of this high-entropy metallic glass. On the one hand, physical aging below the glass transition temperature introduces the annihilation of potential shear transformation zones which contribute to creep. On the other hand, cyclic loading can tailor the “forward” jump operations competing with the “backward” ones of shear transformation zones by controlling the interval time (recovery time). The current research offers a new pathway towards understanding the creep mechanism of high-entropy metallic glasses.

PROPERTIES OF Al-Zn-Mg-Cu ALLOY WHEN MODIFIED BY La, Ce, AND THERMAL-MECHANICAL

The influence of La, Ce elements and thermal-mechanical treatment on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy are presented in this study. According to the results, when the alloy was added to the La, Ce elements, after casting, the grain size of samples was around 40-50µm compared to that of without about 65µm; and then these impurity samples attained 30µm after homogeneous mixture the grain sizes. After the cold deformation process, the distance between plates is 10µm. This homogenization process contributes to increasing the ductility of the studied alloy. In addition, the EDS lines study shows that after the combination of the deformation and heat treatment, the uniformation of elements mainly focuses on the boundary and in the grain. After recrystallization annealing, the grain size is around 10 µm with the modification sample. Further, as a result of ability deformation from the tensile test, these results demonstrate that the tensile test obtained 140 % when adding La, Ce contents into the alloy combined with thermal-mechanical treatment. The combined use of La; Ce and thermal-mechanical treatment have increased the ductility of Al-Zn-Mg-Cu alloy. The combination of modification and thermal-mechanical treatment has created a small grain size for the studied alloy.

Research on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy when modified by La, Ce and thermo-mechanical treatment

Influence of rare-earth (La, Ce) and thermo-mechanical treatment on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy are presented in this article. After casting, the alloy which was modified by La, Ce, the grain size of samples obtained around 40–50 µm compared to that of without about 65 µm; and after homogeneous, the grain sizes is about 30 µm. After the cold deformation process, the distance between plates is 10 µm. By EDS after casting, the samples have tended to more La, Ce elements at the grain boundary, after homogeneous, the uniformation distribution of rare-earths was presented by mapping of EDS’s results. In addition, after rolling and heat treatment, the elements were found on the grain boundary and matrix. After recrystallization annealing, the grain size is around 10 µm with the modification sample. The grain size was reduced by two processes of modification as well as thermal-mechanical treatment is a condition for increasing the ductility of the studied alloy. Further, as a result of ability deformation from the tensile test, these results demonstrate that the tensile test obtained 140 % when adding La, Ce contents into the alloy combine with thermal-mechanical treatment. The combined used of La, Ce and thermal-mechanical treatment have increased the ductility of Al-Zn-Mg-Cu alloy

Comprehensive insights into the thermal and mechanical effects of metallic glasses via creep

• Evolution of deformation and relaxation behavior of a Zr-based MG was explored by extensive creep tests under physical aging and cyclic loading. • Relaxation-time spectra were further utilized to quantitatively describe the time scales involve in the creep of MGs. • An annihilation of local deformation units during physical aging and cyclic loading was detected through the diminution of amplitude in both activation energy and relaxation-time spectra. Evolution of deformation and relaxation behaviors of a prototypical Cu 46 Zr 46 Al 8 metallic glass was explored by extensive creep tests under both physical aging and cyclic loading. Deep insights into the microstructure-induced dynamic heterogeneity which accommodates creep deformation were successively revealed via experimental measurements and spectral analyses. An annihilation of local defects within metallic glass with increasing annealing time and cyclic numbers was observed through the reduction of amplitude in both activation energy spectra and relaxation-time spectra, which were also accompanied by an ascending value of β K W W . It is further found that the corresponding deformation units within the metallic glass do not disappear permanently, but are recoverable over the course of cyclic loading. The apparent suppressed relaxation process can be gradually alleviated with increasing resuming time between two consecutive cycles, behaving differently from physical aging, which indicates a notable discrepancy between thermal treatment and mechanical treatment.

Эволюция дефектной структуры в процессе длительного нагружения ультрамелкозернистого титана ВТ1-0, полученного при воздействии интенсивной пластической деформации

For high-strength titanium VT1-0, the ultrafine-grained structure of which was obtained by mechanical-thermal treatment using the methods of helical and longitudinal rolling followed by annealing to relieve stress of the first kind. The effect of long - term loading in the creep mode at elevated temperature on the size and shape of grains has been studied. A similar study was previously carried out for recrystallized coarse-grained titanium transferred from the ultrafine-grained state by isothermal annealing. Based on the data obtained in the work and the previous results of the authors, the factors affecting the mechanical stability (durability) of ultrafine-grained metals obtained under severe plastic deformation were analyzed.

Evolution of the defective structure during long-term loading of ultrafine-grained titanium VT1-0 obtained by intensive plastic deformation

For high-strength titanium VT1-0, the ultrafine-grained structure of which was obtained by mechanical-thermal treatment using the methods of helical and longitudinal rolling followed by annealing to relieve stress of the first kind. The effect of long-term loading in the creep mode at elevated temperature on the size and shape of grains has been studied. A similar study was previously carried out for recrystallized coarse-grained titanium transferred from the ultrafine-grained state by isothermal annealing. Based on the data obtained in the work and the previous results of the authors, the factors affecting the mechanical stability (durability) of ultrafine-grained metals obtained under severe plastic deformation were analyzed. Keywords: creep, durability, nanopores, ultrafine-grained metals, titanium, recrystallization.

A multiphase strengthened Cu-Nb-Si alloy with high strength and high conductivity

There is a challenging trade-off between the high strength and high electrical conductivity in copper-based alloys. Designed Cu-3.65 wt%Nb (CN) and Cu-3.48 wt%Nb-0.11 wt%Si (CNS) alloys were fabricated by vacuum melting and followed by thermal-mechanical treatment. Microstructure evolutions and properties measurements were studied. Results indicate that morphologies of the Nb 3 Si phase in the CNS alloy are solid or hollow regular polygons whose boundaries are parallel to one of Nb 3 Si's crystal faces. The Nb 3 Si's precipitation can effectively improve the strength, while the Nb 3 Si tip is easy to form stress concentration, which leads to crack and failure. The high electrical conductivity of the CNS alloy was because of the decomposition precipitation of Nb and Nb 3 Si during aging treatment. After hot-rolled by 80% at 900 °C, cold-rolled with a strain of 2.30, the ultimate tensile strength of CN and CNS alloys were 488 MPa and 510 MPa, electrical conductivities were 88.06%IACS (International Annealed Copper Standard) and 93.20%IACS, and elongation rates were 9.3% and 7.1%, respectively. These findings reported a new method to fabricate high-strength and high-conductivity copper alloy. • A multiphase strengthened Cu-Nb-Si alloy with high strength and conductivity was fabricated. • Nb 3 Si particles' morphologies are mainly solid or hollow regular polygon and controlled by crystal surface energy. • The Nb 3 Si particles have a stress concentration at the boundary, which caused transverse cracks.

Preparation and application of expanded and exfoliated vermiculite: A critical review

Vermiculite (VMT) has a unique characteristic of volume expansion after heating, forming highly porous material called expanded VMT, which can be further exfoliated into two-dimensional nanosheets. In this review, we summarized the preparation methods of expanded and exfoliated VMT, as well as the preparation mechanism. The methods to prepare the expanded VMT and exfoliated VMT are partly similar, which include thermal treatment, chemical treatment, and mechanical treatment. Among them, thermal treatment is generally used for expanding VMT. The intercalation treatment is used both for expanding and exfoliating VMT, and mechanical treatment is only used for exfoliating VMT. Meanwhile, we also reviewed the major applications of expanded and exfoliated VMT respectively. The applications of the expanded VMT mainly include environment adsorption, energy storage, flame retardant. Compared with the expanded VMT, the VMT nanosheets with larger specific surface area and more reactive sites provides the opportunities for the exfoliated VMT to serve as nanocomposite materials for nanofluidic channels and intelligent responses besides the above-mentioned applications. However, it is noting that the application of VMT nanosheets is still in its infancy and the exfoliated VMT nanomaterials still have a lot of potentials. The major goal of this review is to reveal the recent progress of expanded and exfoliated VMT in various practical and potential applications and help the researchers to develop more multifunctional materials from VMT.

A Review of Key Technologies and Properties for Graphene Cu-Based Composites

Cu-based composites are widely used in mechanical, electrical, communication, transportation and microelectronics industries due to their excellent properties. However, the difficult match between strength and conductivity is the main problem for Cu-based composites. And thermal-mechanical treatment technologies reached the limit to improve and control their comprehensive performance. Graphene is a two-dimensional layered material with carbon atoms hybridized by SP2 orbital, and has high strength, good electrical conductivity and thermal conductivity. It is expected to solve the contradiction between the strength and conductivity of the composites by introducing graphene into Cu-based composites. In this paper, the commonly used methods for effective dispersion of graphene and interface bonding were introduced, the researches on the strength, toughness, electrical conductivity and thermal conductivity were outlined, lastly the future development of graphene Cu-based composites was prospected.

Macromolecular networks interactions in wheat flour dough matrices during sequential thermal-mechanical treatment

Differences in Mixolab measurements of dough processing were examined using, as a base, flour from pure breeding, isogenic, wheat lines carrying either the high molecular weight glutenin subunits 5 + 10 or 2 + 12. Before dough pasting, subunits 5 + 10 tend to form a stable gluten network relying mainly on disulfide bonds and hydrogen bonds, but 2 + 12 flour was prone to generating fragile protein aggregates dominated by disulfide bonds and hydrophobicity. During dough pasting, a broader protein network rich in un-extractable polymeric proteins, disulfide bonds and β-sheets was formed in the dough with subunits 5 + 10, thus resulting in an extensive and compact protein-starch complex which was characterized by high thermal stability and low starch gelatinization, while in the dough of the 2 + 12 line, a porous protein-starch gel with fragmented protein aggregates was controlled by the combination of disulfide bonds, hydrophobicity and hydrogen bonds that facilitated the formation of antiparallel β-sheets.

Strength-conductivity synergy in cold-drawn reduced graphene oxide (RGO)-aluminum composite wires for electrical applications

We present a breakthrough of the strength-conductivity trade-off in cold wire drawn reduced graphene oxide (RGO)-aluminum (Al) composite. The composite was fabricated by a full glovebox powder metallurgy process, followed by hot rolling and wire drawing down to 0.5 mm wire diameter. Compared to the unreinforced Al fabricated by the same methodology, the incorporation of RGO in the 0.5 mm wire sample gave rise to approximately 20.7% improvement in mechanical strength, with only ~3.6% sacrifice in electrical conductivity. Furthermore, the 331.6 ± 6.8 MPa compressive strength and ~54.1%International Annealed Copper Standard (IACS) of the 0.5 mm wire RGO-Al composite exhibited a strength-conductivity combination comparable or even superior to conventional Al alloy conductors that go through complex thermal-mechanical treatments. Such a property synergy was interpreted by the ultra-fine Al grain structure and the elongated grain morphology rendered by the deformation processing steps, and an Orowan-typed strengthening mechanism owing to the homogenously dispersed natural amorphous alumina and RGO nanosheets in the composite.

Designing damping capacity in high strength Fe–Mn based alloys by controlling crystal defect configurations

ABSTRACT The effects of different thermal–mechanical treatments on defect configurations and damping capacity were investigated in a cold-drawn Fe–17.5Mn–0.022C alloy to further clarify the main damping sources and thus to enhance the damping capacity in high strength Fe–Mn based alloys, especially at low strain amplitudes. The results showed that the damping capacity at the low strain amplitude of 4 × 10−4 in the quenched alloy increased by 176% after ageing and deformation. The amount of the stacking faults and the mobility of associated Shockley partial dislocations control the damping capacity in high strength Fe–Mn based alloys. Atoms segregation to the stacking faults pins the movement of partial dislocations more strongly than vacancies did. Both increasing the amount of the stacking faults and reducing the pinning of Shockley partial dislocations are direction for designing the high strength Fe–Mn alloys with high damping capacity.

High-entropy alloys: Structure, mechanical properties, deformation mechanisms and application

The article considers a brief review of the foreign publications on the study of the structure, phase composition and properties of five-component high-entropy alloys (HEAs) in different structural states in a wide temperature range over the past two decades. HEAs attract the attention of scientists with their unique and unusual properties. The difficulties of comparative analysis and generalization of data are noted due to different methods of obtaining HEAs, modes of mechanical tests for uniaxial compression and tension, sizes and shapes of the samples, types of thermal treatments, and phase composition (bcc and fcc crystal lattices). It is noted that the HEA with a bcc lattice has mainly high strength and low plasticity, and the HEA with a fcc lattice has low strength and increased plasticity. A significant increase in the properties of the FeMnCoCrNi HEA with a fcc lattice can be achieved by alloying with boron and optimizing the parameters of thermal mechanical treatment at alloying with carbon in the amount of 1 % (at.). The deformation curves analyzed in the temperature range –196 ÷ 800 °C indicate an increase in the yield strength with a decrease in the grain size from 150 to 5 microns. As the temperature decreases, the yield strength and elongation increase. The effect of deformation rate on the mechanical properties is an increase in the ultimate strength and yield strength, which is most noticeable at high rates of 10–2 ÷ 103 s–1. The features of HEAs deformation behavior in the mono- and poly-crystalline states are noted. The complex of high operational properties of HEAs makes it possible to use them in various industries. There are good prospects of using energy treatment to modify the surface layers and further improve HEAs properties.

Strain Hardening of Low-Carbon Steel in the Area of Jerky Flow

Purpose. The aim of this work is to assess the effect of ferrite grain size of low-carbon steel on the development of strain hardening processes in the area of nucleation and propagation of deformation bands. Methodology. Low-carbon steels with a carbon content of 0.06–0.1% C in various structural states were used as the material for study. The sample for the study was a wire with a diameter of 1mm. The structural studies of the metal were carried out using an Epiquant light microscope. Ferrite grain size was determined using quantitative metallographic techniques. Different ferrite grain size was obtained as a result of combination of thermal and termo mechanical treatment. Vary by heating temperature and the cooling rate, using cold plastic deformation and subsequent annealing, made it possible to change the ferrite grain size at the level of two orders of magnitude. Deformation curves were obtained during stretching the samples on the Instron testing machine. Findings. Based on the analysis of stretching curves of low-carbon steels with different ferrite grain sizes, it has been established that the initiation and propagation of plastic deformation in the jerky flow area is accompanied by the development of strain hardening processes. The study of the nature of increase at dislocation density depending on ferrite grain size of low-carbon steel, starting from the moment of initiation of plastic deformation, confirmed the existence of relationship between the development of strain hardening at the area of jerky flow and the area of parabolic hardening curve. Originality. One of the reasons for decrease in Luders deformation with an increase of ferrite grain size of low-carbon steel is an increase in strain hardening indicator, which accelerates decomposition of uniform dislocations distribution in the front of deformation band. The flow stress during initiation of plastic deformation is determined by the additive contribution from the frictional stress of the crystal lattices, the state of ferrite grain boundaries, and the density of mobile dislocations. It was found that the size of dislocation cell increases in proportion to the diameter of ferrite grain, which facilitates the development of dislocation annihilation during plastic deformation. Practical value. Explanation of qualitative dependence of the influence of ferrite grain size of a low-carbon steel on the strain hardening degree and the magnitude of Luders deformation will make it possible to determine the optimal structural state of steels subjected to cold plastic deformation.

Influence of degree of deformation on welding pore reduction in high-carbon steels

Locally adapted properties within a machine component offer opportunities to increase the performance of a component by using high strenght materials where they are needed. The economic production of such hybrid components on the other hand represents a major challenge. The new tailored forming process chain, which is developed within the collaborative research center (CRC 1153) represents a possible solution to produce hybrid components. This is made possible by the use of pre-joined hybrid semi-finished products made from two different steel alloys, which are subsequently formed. The semi-finished products can be manufactured for example by means of deposition welding. Due to a thermal mechanical treatment, an overall higher component strength of the joining zone can be achieved. The deposition welding processes can be used to generate a cladding on a base material. During the welding, one of the most difficult tasks is to reduce the amount and size of pores in the joining zone. These pores can reduce the strength in the joining zone of the welded parts. However, additional pores can occur in the intermediate zone between the substrate and the cladding. In the presented study, the influence of the forming process on the closing of pores in the cladding and in the intermediate zone was investigated. Therefore, cylindrical specimen were extracted in longitudinal direction of the welding track by wire-cut eroding. These welding tracks are manufactured by plasma-transferred arc welding of AISI 52100 on a base plate made of AISI 1015. Further, specimens were prepared transversely, so that the base material, the intermediate layer, and the welded material are axially arranged in the specimen. The prepared specimen were checked for pores by means of scanning acoustic microscopy. Subsequently, an uniaxial compression test was carried out with various degrees of deformation and the two specimen designs were examined again for pores. A microstructure analysis was carried out after each step. The investigations show that there is a need for a minimum degree of deformation to reduce pores in the welded material. However, this required plastic strain cannot be achieved in the welded material of the hybrid specimen, which is a result of the homogeneous temperature distribution in the specimen. The homogeneous temperature distribution leads to different flow properties in the specimen, which means that the main plastic deformation is taking place in the base material.

Microstructure and Hardening Behavior of Argon-Ion Irradiated Steels 18Cr10NiTi and 18Cr10NiTi-ODS

Microstructure and nanohardness evolution in 18Cr10NiTi and 18Cr10NiTi-ODS steels after exposure to argon ion irradiation has been studied by combination of nanoindentation tests, XRD analysis, TEM and SEM observation. ODS-modified alloy was produced on the basis of conventional 18Cr10NiTi austenitic steel by mechanical alloying of steel powder with Y(Zr)-nanooxides followed by mechanical-thermal treatment. XRD analysis has showed no significant changes in the structure of 18Cr10NiTi steel after irradiation at room and elevated temperatures (873 K) and in ODS-steel after irradiation at 873 K, whereas the evidences of domains refinement and microstrain appearance were revealed after irradiation of 18Cr10NiTi-ODS steel at room temperature (RT). Layer-by-layer TEM analysis was performed to investigate the microstructure of alloys along the damage profile. The higher displacement per atom (dpa) and Ar concentration clearly lead to increased cavities size and their number density in both steels. The swelling was estimated to be almost half for 18Cr10NiT-ODS (4.8%) compared to 18Cr10NiTi (9.4%) indicating improved swelling resistance of ODS-steel. The role of oxide/matrix interface as a sink for radiation-induced point defects and inert gas atoms is discussed. The fine dispersed oxide particles are considered as effective factor in suppressing of cavity coarsening and limiting defect clusters to small size. The hardness behavior was investigated in both non-irradiated and irradiated specimens and compared to those at RT and elevated temperature of irradiation. The hardness increase of unirradiated ODS-steel is associated mainly with grain refinement and yttrium oxides particles addition. The hardening of 18Cr10NiTi-ODS after Ar ion irradiation at RT was found to be much lower than 18Cr10NiTi. Black dots and dislocation loops are observed for both steels in the near-surface area; however, the main hardening effect is caused by the cavities. Oxide dispersion strengthened steel was found to be less susceptible to radiation hardening/embrittlement compared with a conventional austenitic steel.