Microstructure Of Specimens Research Articles

EXPERIMENTAL INVESTIGATION ON ENERGY CONSUMPTION AND SURFACE FINISH IN TURNING OF Al-4032/6% SiC COMPOSITE FABRICATED THROUGH STIR CASTING

The aluminum-based composites (AMCs) are known for a variety of functions like building, aerospace, automotive, marine, and aeronautical applications. In this research, Al-4032 alloy-based 6% SiC (by weight) composite has been fabricated using stir casting and the effects of prominent machining parameters on energy consumption and surface finish have been examined using carbide inserts in turning. Microstructures of as-cast specimens has been analyzed using the optical microscope, scanning electron microscopy, and energy-dispersive spectroscopy. The CNC turning has been performed at varying machining parameters like cutting speed, feed rate, and depth of cut, following an RSM-based design matrix. The desirability function approach has been employed to obtain the best combination of parameters for achieving the desired objectives. The experimental outcome demonstrates that the machined composite is considerably influenced by built-up edge (BUE) formation and interfacial bonding of particles. The result establishes that the inclusion of SiC in the Al-4032 matrix demonstrates improved mechanical properties and superior machined surface with the optimized turning operation.

Agricultural waste and natural dolomite for green production of aluminum composites

Metal matrix composites (MMCs), and particularly aluminum matrix composites (AMCs), are beginning to make a substantial contribution to aerospace, automotive, and electronic industry application after more than a quarter-century of intensive study. To fabricate a cost-effective AMC with outstanding mechanical and physical properties the present work utilized two types of natural base reinforcement materials for elaborating AMCs by powder metallurgy technology (PM). The reinforcement materials were an agricultural waste (date palm seeds) and dolomite rocks at 2.5, 5, 7.5, and 10% weight in addition to the aluminum matrix. The morphological and solid-phase characteristics were examined for the fabricated AMC specimens. These tests include X-ray diffraction, and optical and scanning microscopy. The microstructure of the fabricated specimens for both reinforcement materials showed uniform particle size distribution of the waste enforcement material as the PM technology was satisfactory in embedding the waste particles within the aluminum. The AMCs prepared were subjected to different mechanical loads and it was found that the composite reinforced with date palm seeds possess a high hardness property. A higher hardness of 50 HRV at 7.5% enforcement of date palm seeds was obtained compared to dolomite reinforced composite which showed 48.3 HRV at 7.5% enforcement. For the compressive strength, the date palm seeds composite resisted 23.8 MPa at 7.5% and only 16.68 MPa was obtained as a maximum compression resistance for the dolomite reinforced aluminum composite.

Effect of TiC on the microstructure of GTD-111 superalloy processed by laser powder bed fusion

• TiC particles cause heterogeneous nucleation by altering the diffusion field in LPBF. • GBs liquation and GBs cracking is the most important LPBF problem in GTD-111. • The addition of TiC to GTD-111 causes the formation of equiaxed grains and zigzag of GB. • The favorable thermal conductivity of TiC prevents crystal formation in the GTD-111 matrix. • GTD-111 composite with TiC reduces the tendency of GB cracking by increasing C-GBLD. In this study, the microstructure of specimens made of GTD-111 superalloy was modified by laser powder bed fusion with TiC nanoparticles. The results showed that TiC particles acted as heterogeneous nucleation for solidification and caused grain refinement, equiaxed grain formation, grain boundary length reduction, increase of large angle grain boundaries, zigzagging of grain boundary, reduction of cracks and porosity and also reduces the segregation of elements sensitive to melting cracks. The combination of the above factors reduced the grain size by adding TiC by 40%.

Analisa Pengaruh Variasi Waktu Penahanan Panas Dengan Proses Normalizing Pada Baja ST 41 Terhadap Kekerasan Dan Struktur Mikro

The normalizing heat treatment process was carried out on ST 41 steel, a medium carbon type steel at 850°C heating with variations in holding time of 15 minutes, 20 minutes and 25 minutes with air cooling media. This study determines the hardness and microstructure variations in holding time using air cooling media. The result of this study indicates that the (holding time) factor effect the hardness value, the indentation trace's depth value, and the research specimen's microstructure. The first specimen using a holding time of 15 minutes has a hardness value of 68, 25 HRB with an indentation depth of 0,063 mm. The specimen with a holding time of 20 minutes has a hardness value of 70 HRB with an indentation depth 0,058 mm, and a specimen with a holding time 25 minutes has a hardness value of 68 HRB with an indentation depth of 0,063 mm. The hardness test result found that the specimens with variations in holding time 25 minutes had a smaller hardness value and a deeper depth than variations in holding time of 15 minutes and 20 minutes. Furthermore in the microstructure of specimens with a holding time of 25 minutes, the ferrite phase was more dominant than specimens with holding time of 15 minutes and 20 minutes. The phase that appeared at the holding time of 25 minutes was 80,367 % ferrite phase and 19,633 % pearlite phase. So at a holding time of 25 minutes, the ferrite phase is more dominant, so the hardness value of ST 41 steel decreases.

Modelling and Experimental Study of Dissimilar Arc Stud Welding of AISI 304L to AISI 316L Stainless Steel

This paper has aimed to try and establish a successful weld joint between AISI 304L stainless steel as a stud and AISI 316L stainless steel as a plate by using an arc stud welding process. The effect of different current and time welding on the torque results was experimentally studied, by using three-level of each process parameters. The post-weld heat treatment (PWHT) was carried out on the optimum sample of torque, to study the effect of PWHT on mechanical properties (torque and hardness) and microstructure of the welding zone. In the present work, a3-D finite element model was developed by using ANSYS software version 18 to analyze the influence of time and current welding on the temperature distribution and residual stresses of the resultant welded joints. A transient thermal model was built to predict the temperature distribution whereas the residual stresses were determined by using a static structural model. The PWHT has been used to reduce the amount of residual stresses and enhance the mechanical properties of the welded joint. The micro-hardness based on the Vickers test and the microstructure of welded specimens of with and withoutPWHT have been investigated. The simulation results reveal that the generated temperature and the residual stress is strongly affected by the time and current welding. The mechanical test results indicated that the PWHT prompted an improvement in the hardness values.

Enhancing the tensile properties of PA6/CNT nanocomposite in selective laser sintering process

AbstractThe aim of present study is to enhance the tensile strength, elongation at break and tensile modulus of polyamide 6/carbon nanotube (PA6/CNT) nanocomposite prepared by selective laser sintering. For this purpose, the optimal values of laser power, scanning speed and CNT content were estimated to enhance the tensile properties of PA6/CNT nanocomposite by using the response surface methodology and desirability function. The microstructure of specimens was observed using the scanning and transmission electron microscopy. It was observed that an increase in laser power from 5 to 10 W improved the tensile strength (21%) and elongation at break (11.4%) of the nanocomposite due to uniform dispersion of CNTs, while the further increase of laser power reduced the tensile strength (5.2%), elongation at break (5.8%) and tensile modulus (5.3%) due to thermal degradation of PA6 polymer. A rise of the scanning speed from 1000 to 2000 mm/s was associated with a reduction in the tensile strength, elongation at break and tensile modulus by about 8.3%, 13% and 3.3% respectively, which was due to lower heat input and consequently incomplete densification of the nanocomposite. The addition of CNTs up to 5 wt% can enhance the tensile properties of PA6/CNT nanocomposite, but needs increasing the laser power. The best combination of tensile properties was achieved at laser power of 7.3 W, scanning speed of 1000 mm/s and CNT content of 1.8 wt%. Moreover, the addition of CNTs up to 5 wt% showed a slight influence on thermal stability and crystallinity of the sintered nanocomposite.

Investigation the effect of freeze–thaw cycle on fracture mode classification in concrete based on acoustic emission parameter analysis

This study experimentally investigates the influence of freeze–thaw (F-T) cycles on the mechanical properties and cracking features of concrete. The specimens, which are previously subjected to various numbers of freezing (-20 °C) and thawing (20 °C) cycles, are tested under unixial compression condition. Integrated acoustic emission (AE) and digital image correlation (DIC) techniques are adopted to study the mechanical characteristics of the concrete specimen subject to different F-T cycles under different immersion condition. The micro-structure of the concrete specimen after F-T cycle treatment is observed with T2 distribution by the nuclear magnetic resonance (NMR) technology. The changes in the amount of uniaxial compressive strength (UCS), elastic modulus, and peak strain of the specimens before and after various F-T cycles are comprehensively analyzed. The results show that the brittleness of the specimen decreases and the ductility increases as the number of F-T cycle increases. The peak load and elastic modulus decreased gradually with the increase of F-T cycle times, and the peak strain presented an upward trend. The concrete specimens without F-T cycle action or subjected to less F-T cycles action suddenly lose their bearing capacity and the failure mode is shear slipping. For the specimens undergoing more F-T cycles action, the stress–strain curve exhibits lower slopes during the strain softening stage. Kernel density estimation (KDE) results show that under the lower F-T cycle, the tensile crack has a higher AF (acoustic emission count/duration) value and a lower RA (rise time/amplitude) value, and the obvious shear/mixed cracking phenomenon occurs after the higher F-T treatment. The K-means clustering method has its advantages in the classification of AE cracking events. The b value increased with the increase of F-T cycles, indicating that F-T cycles can caused internal damage of the specimens, and the degree and scale of internal damage increased with the increase of F-T treatment times. Furthermore, the damage degree of the specimens under semi-immersion in water solution is greater than that under complete immersion in water solution.

Effect of electroshocking treatment on the microstructure and mechanical properties of laser melting deposited near-β Ti-55531 thin-wall

The near-β Ti-55531 (Ti-5Al-5Mo-5V-3Cr-1Zr, wt%) alloy with thin-wall structures were manufactured by laser melting deposition (LMD), and followed by the post-processing of electroshocking treatment (EST). The microstructure evolution before and after EST were characterized via using the scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The results showed that the microstructure of as-deposited specimen was mainly composed of short columnar grains and equiaxed grains, showing a unique structure of alternating short columnar grains-equiaxed grains-short columnar grains. The results of EBSD showed that EST could reduce the orientation concentration and weaken the texture of β phase. XRD results indicated that the α phase content slightly increased after EST. The micro-strain and lattice constant of β phase were changed after EST, which were probably ascribed to the precipitation of α, the generation of crystal defects on α/β interface, and the decrease of texture intensity. The results of mechanical properties indicated that EST could increase the microhardness, the yield strength and the tensile strength, which were due to the variation of microstructure. All results show that EST is an effective approach for optimizing the microstructure and improving the mechanical properties of LMD near-β titanium alloy.

Aquatic Weed for Concrete Sustainability

Ordinary Portland cement (OPC) is the primary binder of concrete, accounting for approximately 5% to 7% of greenhouse gas (GHG) and carbon dioxide (CO2) emissions with an annual production rate of more than 4 billion tons. It is critical to reduce the carbon footprint of concrete without sacrificing its performance. To this end, this study focuses on the use of water hyacinth ash (WHA) as a pozzolanic binder in the production of concrete as a partial replacement for cement. Four mixes are designed to achieve C-25-grade concrete with varying proportions of cement replacement with WHA of 0%, 5%, 10%, and 15% of the cement weight. Extensive experiments are performed to examine the workability, strength, durability, and microstructure of concrete specimens. The test results confirm that incorporating WHA in concrete improved its workability, strength, and durability. The optimal results are obtained at the maximum OPC replacement level, with 10% WHA. The use of WHA as a partial replacement for cement greatly reduces the energy required for cement production and preserves natural resources. More research is needed to use WHA on a large scale to achieve greater sustainability in the concrete industry.

Enhancing the Surface Quality of FDM Processed Flapping Wing Micro Mechanism Assembly through RSM–TOPSIS Hybrid Approach

Improving surface quality attributes is a critical task in the production of micro-sized near-net-shaped components for end-use applications using additive manufacturing techniques. In the present study, we investigated the effect of fused deposition modeling (FDM) process parameters such as layer thickness, part orientation, raster width and raster angle on the surface quality characteristics of as-fabricated test specimens in order to develop the assembly of a flapping wing micro mechanism. Through a Box–Behnken design, a suitable experimental strategy was developed, and test specimens were manufactured. The performance of the experiments was statistically assessed using multi-response analysis of variance (ANOVA). The microstructures of the test specimens produced with various processing parameters were examined using a scanning electron microscope to identify micro surface flaws under various processing conditions. Furthermore, the optimal FDM parameters for improved surface quality attributes such as Ra, Rz and Rq were obtained using a statistical optimization technique known as Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS).

Effect of post-treatment on the microstructure and properties of Ti-27 Nb-5Zr-2Cr alloy prepared by laser powder deposition

A metastable titanium alloy of Ti-27 Nb-5Zr-2Cr (wt%) was fabricated by laser powder deposition (LPD), and the bulk samples were then treated with hot forging (HF) and hot forging + surface shot blasting (HF + SB). The microstructures and mechanical properties of the laser-deposited Ti-27 Nb-5Zr-2Cr alloy in LPD, LPD + HF, and LPD + HF + SB were investigated. The obtained results showed that the microstructure of the LPD specimen was composed of β phase and isothermal ω phase. Due to the exist of the isothermal ω phase, the alloy was significantly strengthened and the deformation twinning was suppressed completely. As a result, the LPD specimen exhibited high strength (yield strength 728 ± 72 MPa) but low plasticity (6 ± 1%); after hot forging, the isothermal ω phase transformed to β phase and the deformation twinning occurred during tensile deformation. The yield strength and tensile strength of LPD-HF specimen decreased by 45% and 29%, respectively, but the plasticity increased by 483% to 35 ± 2%. Shot blasting was used to introduce gradient nanostructures on the surface of LPD-HF-SB specimens, which suppressed surface wrinkling caused by deformation twinning while improving strength and plasticity. Compared with the LPD-HF specimen, the yield strength, tensile strength, and plasticity of the LPD-HF-SB specimen were increased by 18%, 8%, and 6%, respectively.

Effects of TiO2-Modified RGO Composites on the Mechanical and Durability Properties of Ordinary Portland Cement Mortars

Various applications of graphene-based materials in construction are an alternative to improve the properties of ordinary Portland cement (OPC)-based binders. This paper used a titanium dioxide in situ intercalation method to enhance the dispersibility of reduced graphene oxide (RGO) and then explored the effects of the incorporation of the obtained TiO2–RGO composite and RGO on the mechanical and durability-related properties of the OPC-based binders. Experimental results showed that TiO2 was successfully intercalated into the RGO layers and could improve the dispersion of RGO in water or synthesized OPC pore solution significantly, probably due to the greater spacing between each RGO layer. Besides, a proper amount of TiO2-modified RGO composite (0.03 wt % in this study) could elevate the mechanical strengths of OPC mortars, evidenced by a large increment of 24.78% and up to 34.94% in the compressive strength and flexural strength, respectively. The TiO2–RGO composite led to higher flexural-to-compressive strength ratios with the given dosages (0.01–0.05 wt %), implying a higher fractural toughness. Moreover, the resistance of the enhanced OPC-based mortars toward chloride attacks and freeze–thaw cycles was significantly improved. Based on the microstructural analyses including scanning electron microscopy and X-ray diffraction results, it is found that the modified RGO could to some extent promote the hydration of OPC and densify the overall microstructure of bulk specimens, leading to enhanced mechanical and durability properties. Compared to normal RGO, the TiO2–RGO composite was more effective in enhancing the properties of OPC mortars, due in large part to its better dispersion state.

Prediction of bulk mechanical properties of PVC foam based on microscopic model:Part I-Microstructure characterization and generation algorithm

The mechanical properties of porous materials greatly depend on their microstructures, so the generation of realistic microstructures is the premise for a sound numerical simulation and analytical prediction. This paper presented the microstructure generation of three kinds of transversely isotropic closed-cell polyvinyl chloride (PVC) foams with different densities based on the geometric characteristics obtained from the X-ray computed tomography (CT) technology. Advancing front method was used to densely pack a set of spheres whose volume distribution is proportion to the cell volume distribution and the microstructure was formed by Laguerre tessellation. Then the geometric characteristics of the numerical models were compared with those from the CT. The good consistence proves that the proposed method is accurate and efficient to produce the representative microstructure of the PVC foams. Finally, a method was proposed to optimize the microstructure of small size numerical specimens, by which the small specimens could give similar geometric characteristics to those of the large specimens.

Investigation of the microstructure, machinability and hole quality of AISI 1045 steel forged at different temperatures

In this study, AISI 1045 steel material was hot forged at 1100, 1150, 1200 and 1250°C temperatures. The microstructure and hardness of the test specimens after forging were investigated. The non-forged samples and forged samples were drilled with 6.8 mm diameter solid tungsten carbide drills. Drilling tests were performed in 80 and 120 m/min cutting speed combinations and 0.15, 0.20 and 0.3 mm/rev feed rate. After drilling operations progress forces, surface roughness, roundness deviation, the deviation from cylindricity and taper were investigated. It has been determined that AISI 1045 steel consists of ferrite + pearlitic microstructure and its hardness increases due to the removal of microvoids and pores by forging. It was also determined that the hardness of the samples decreased due to the coarsening in grain size depending on the cooling time with the increase of the forging temperature. It was observed that the feed force obtained during the drilling of the untreated sample in the perforation process was less than the values obtained during the drilling of the hot forging process samples. However, it was found that the measured surface roughness, roundness, cylindricity and conicity values of an untreated sample were more than the hot forging treated sample. It was observed that this situation was caused by the difficulties experienced in sawdust evacuation due to the longer hole length of the untreated sample. Feed rates, surface roughness, roundness, cylindricity and taper values decreased with increasing forging temperature. This situation arises from the decrease in the feed rate due to the decrease in the hardness of the samples, which occurs with the increase in the forging temperature. With the hot forging process applied to the untreated A sample, the hardness values of the forged samples increased between about 8.7 and 10%. The increase in feed force was between 11 and 20%. Surface roughness, Circularity, Cylindricity and Taper values decreased between 40 and 98% compared to the untreated A sample.

Effect of the subsidiary materials of the manufacturing process on the microstructure of the composite laminate

AbstractComposite specimens with resin contents of 33.5%, 35.4%, and 35.9%, respectively, were manufactured by controlling the type of subsidiary material used in the bagging process for a composite material having the same composition. The effect of controlling the resin content on the microstructure and mechanical properties of composite specimens was investigated. The flow of resin and air during the cure process was inferred and explained by connecting it with the microstructure. Specifically, the behavior of the resin determined the thickness, density, and void of the composite laminate, which acted as a factor causing the difference in mechanical properties of the composite materials. As the resin content increased, there was no significant difference in tensile strength, but Young's modulus decreased. In the case of the compression test, there was a difference in mechanical properties due to the combined effect of the reinforcement and the resin. The maximum compressive strength value was shown in the process with low void content, and Young's modulus tended to decrease as the resin content increased. In the bagging process, the subsidiary material controlled the flow of resin and air, and caused a difference in microstructure, affecting the change of mechanical properties.

Synergistic effect of Ti, B, Si, and C on microstructure and mechanical properties of as-cast Al0.4Co0.9Cr1.2Fe0.9Ni1.2(Si, Ti, C, B)0.375 complex concentrated alloy

The synergistic effect of Ti, B, Si, and C on microstructure and mechanical properties of as-cast Al0.4Co0.9Cr1.2Fe0.9Ni1.2(Si, Ti, C, B)0.375 complex concentrated alloy (CCA) was studied. The as-cast alloy was prepared by vacuum induction melting in a ceramic crucible followed by a tilt casting to a graphite mould. The effect of alloying elements on the primary solidification phase, solidification path, and phase transformation temperatures is evaluated. The solidification of the alloy starts with the growth of columnar FCC(A1) (face-centred cubic crystal structure A1) dendrites and is finalised by the formation of lamellar FCC(A1) + (Ni,Co,Fe)16(Ti,Cr)6(Si,Al)7 eutectic in the interdendritic region. During solidification, Al, Ti, B, Si, and C segregate preferentially to liquid, which leads to the formation of BCC(B2) (ordered body-centred cubic crystal structure B2), BCC(A2) (body-centred cubic crystal structure A2), FCC(A1), (Ni,Co,Fe)16(Ti,Cr)6(Si,Al)7, Cr2B, and TiC phases in the interdendritic region. The highly anisotropic microstructure of tensile specimens prepared from the as-cast alloy consists of columnar FCC(A1) dendrites (89 vol%) oriented at an angle ranging from 75 to 90 degrees to the longitudinal axis of specimens and multiphase interdendritic region (11 vol%). The tensile deformation curves show only the strain hardening stage at test temperatures up to 700 °C. The strain hardening coefficient decreases from 0.20 to 0.17 by increasing the test temperature from 20° to 700°C. At temperatures ranging from 725° to 900°C, the tensile curves show the strain hardening stage, which is followed by the strain-softening stage up to a fracture. The strain softening stage results from dynamic recrystallisation of FCC(A1) dendrites and fracture of brittle high elastic modulus phases in the interdendritic region.

Microstructural and mechanical properties of AISI 440C stainless steel fabricated using selective laser melting

AISI 440C stainless steel (SS440C) has excellent mechanical properties. However, its industrial application is limited because SS440C cannot be fabricated into different shapes due to its high hardness and low workability. Selective laser melting (SLM) is the most suitable method to increase the workability of SS440C because the SLM process has few restrictions on manufacturing geometry. In order to observe changes in internal porosity according to process conditions, specimens under 36 different process conditions were fabricated by SLM. The changes in microstructure and defect generation mechanism in specimens fabricated under high-density process conditions were analyzed. Phase change and mechanical properties of SS440C were studied under defect free process conditions and compared with those observed by researchers in the past.

Effect of solution treatment time on plasticity and ductile fracture of 7075 aluminum alloy sheet in hot stamping process

The effect of solution treatment time on the post-formed plasticity and ductile fracture of 7075 aluminum alloy in the hot stamping process was studied. Tensile tests were conducted on the specimens subjected to the hot stamping process with different solution treatment time. The digital image correlation (DIC) analysis was used to obtain the strain of the specimen. Based on the experiments and modeling, the Yld2000-3d yield criterion and the DF2014 ductile fracture criterion were calibrated and used to characterize the anisotropy and fracture behavior of the metal, respectively. Furthermore, the microstructure of specimens was studied. The experimental and simulation results indicate that the 7075 aluminum alloy retains distinct anisotropy after the hot stamping process, and there is no obvious effect of extending the solution treatment time on the material anisotropy. However, it is found that a longer solution treatment time can increase the fracture strain of the aluminum alloy during the hot stamping process, which may be related to the decrease of the second-phase particles size.

High-precision laser powder bed fusion of 18Ni300 maraging steel and its SiC reinforcement composite materials

Thanks to the need for refinement in the mold field, high-precision laser powder bed fusion (HP-LPBF) has become a critical technique for manufacturing new high-precision molds. The influence of HP-LPBF process parameters for densification of 18Ni300 maraging steel (MS18Ni300), as well as the related optical micrograph (OM), microstructure, phase composition, and mechanical properties of optimal relative density specimens, were comprehensively examined in this study. The sequence of HP-LPBF process parameters on the relative density of the specimens was investigated using the orthogonal experimental method. With a relative density of 99.18 ± 0.11 % and a surface roughness of 3.59 ± 0.32 μm, the optimal process parameters was attained. The influence of adding SiC on the specimens' OM, microstructure, phase composition, and mechanical properties were compared and studied. The results show that the building direction (BD) is the dominant heat flow direction in HP-LPBF by EBSD analysis and that the rotating 67° scanning strategy can effectively improve the isotropy of the mechanical properties of HP-LPBF parts. The MS18Ni300 specimen has a particularly thin cellular microstructures with a diameter of 6.11 μm. In addition, the dominant phase composition of the MS18Ni300 specimen was martensite (α). The microstructure of SiC (volume fraction of 1 %)/MS18Ni300 (M1) composites was significantly refined, and changes in the microstructure were primarily due to SiC's physical properties. The addition of SiC particles leads to a weakening of the preferred crystallographic orientation of the grains. The average grain size was 3.21 μm. No new phases were produced, but the mechanical properties were improved. The ultimate tensile strength and hardness of M1 were 1.33 GPa and 390.2 HV, respectively. The strengthening mechanism of SiC was discussed.

Effect of ion beam radiation on the microstructure and porosity of dysprosium hafnate

This paper looks at the effect of ion beam radiation on a dysprosium hafnate material (Dy2O3 – HfO2) that can potentially serve as a neutron absorber. The study was based on a serial radiography with helium and nickel ions at the temperatures of 350 and 550 oС to the doses of 20, 100, 200 and 300 dpa. Using scanning and transmission electron microscopy, the authors examined the microstructure of specimens both in their initial state and after exposure. Electron probe microanalysis helped determine the concentration of the elements in the specimens. The paper demonstrates that exposure of dysprosium hafnate to a damaging dose of 20 dpa does not lead to any visible structural changes. When the dose exceeded 100 dpa, the authors observed changes in the surface morphology of the specimens and a gradual closing-up of process-related pores. Calculation results indicate that the swelling of the dysprosium hafnate specimens does not exceed 0.1% at the maximum accumulated radiation of 200 to 300 dpa.The authors would like to thank P. S. Dzhumaev, M. S. Staltsov and O. V. Emelianova for their support with scanning electron microscopy and electron probe microanalysis; D. P. Shornikov for his support with systematization and processing of experimental data.