Room Temperature Tensile Properties Research Articles

High-performance ultra-lean biodegradable Mg–Ca alloys and guidelines for their processing

High-performance ultra-lean binary Mg–Ca alloys are engineered by intelligent alloying and thermo-mechanical processing using hot-extrusion. With Ca-alloying contents as low as 0.2-0.6 wt.%, remarkable room-temperature tensile properties are obtained with tensile strength values as high as 380–420 MPa, or ductility values reaching a maximum of 36 %. By means of multiscale structural and chemical analysis using electron microscopy and energy dispersive X-ray spectroscopy, we show that multimodal strengthening mechanisms can be activated by modifying the spatial distribution of Ca as secondary phase. Our results indicate that strong precipitation strengthening is achieved when Mg2Ca phase particles are dispersed within the grains. On the other hand, preferential distribution of the Mg2Ca precipitates along grain boundaries imparts substantial grain-boundary strengthening by the Hall-Petch effect. Apart from secondary-phase precipitation, the role of Ca as solute atoms is paramount in promoting homogeneous deformation. The presence of Ca directly alters the intrinsic stacking fault energies and modifies the cross-slip energy barriers such that the slip-transition probability from pyramidal-to-basal and vice-versa becomes comparable. Both effects ensure competitive activation of basal and non-basal slip, thereby reducing the mechanical anisotropy. The mechanical performance in the current work, when compared to earlier reported studies of Mg alloys with similar or higher alloying content, shows a 2 to 10-fold increase in tensile strength without compromising ductility.

Recent Progress in Creep-Resistant Aluminum Alloys for Diesel Engine Applications: A Review.

Diesel engines in heavy-duty vehicles are predicted to maintain a stable presence in the future due to the difficulty of electrifying heavy trucks, mine equipment, and railway cars. This trend encourages the effort to develop new aluminum alloy systems with improved performance at diesel engine conditions of elevated temperature and stress combinations to reduce vehicle weight and, consequently, CO2 emissions. Aluminum alloys need to provide adequate creep resistance at ~300 °C and room-temperature tensile properties better than the current commercial aluminum alloys used for powertrain applications. The studies for improving creep resistance for aluminum casting alloys indicate that their high-temperature stability depends on the formation of high-density uniform dispersoids with low solid solubility and low diffusivity in aluminum. This review summarizes three generations of diesel engine aluminum alloys and focuses on recent work on the third-generation dispersoid-strengthened alloys. Additionally, new trends in developing creep resistance through the development of alloy systems other than Al-Si-based alloys, the optimization of manufacturing processes, and the use of thermal barrier coatings and composites are discussed. New progress on concepts regarding the thermal stability of rapidly solidified and nano-structured alloys and on creep-resistant alloy design via machine learning-based algorithms is also presented.

AlxHfTaTi (0≤x≤0.5) refractory medium entropy alloys with excellent room-temperature tensile properties

Refractory high entropy alloys are strong candidates for high-temperature structural materials, because of their high strength, excellent thermal stability and exceptional softening resistance under high-temperature. However, majority of the existing refractory high entropy alloys are seriously limited in widespread application, due to their severe brittleness at room temperature. In this study, we proposed a novel AlxHfTaTi body-centered cubic (BCC) refractory medium entropy alloy with remarkable strength-ductility combination at room temperature. Adjusting the atomic ratio of Al (from 0 to 0.5 at.%), we investigated the effect of Al on the structure-property characteristics of the alloy under as-cast as well as cold-rolled and annealed conditions. Compared with the as-cast samples, the rolled and annealed samples exhibit more excellent tensile properties due to the remarkable reduction of grain size resulted from recrystallization. The Al0.3HfTaTi sample annealed for 5 min exhibits outstanding comprehensive properties at room temperature, with a yield strength higher than 1000 MPa and a fracture elongation of up to 24 ± 1 %, respectively. Quasi in-situ EBSD analysis results reveal that, during tensile deformation, the grain size has a significant effect on the grain rotation and dislocation gliding. Small grains are more likely to initiate multiple slip bands, promoting the synergistic effect of grain rotation and dislocation gliding, thereby improving the ductility of the alloy. Our findings can provide new ideas for the development of refractory high entropy alloys with outstanding room-temperature tensile properties.

Comparative Study of the Mechanical Properties and Fracture Mechanism of Ti-5111 Alloys with Three Typical Microstructures

In this work, Ti-5111 alloys with equiaxed, bimodal and lamellar microstructures were prepared by various heat treatment processes. The room-temperature tensile properties, deformation microstructure and fracture mechanism of the alloys with different microstructures were investigated. Furthermore, the mechanism by which the microstructure affects the mechanical properties of Ti-5111 alloys with three typical microstructures was confirmed. The Ti-5111 alloy with a bimodal microstructure has minimum grain size and a large number of αs/β phase boundaries, which are the primary reasons for its higher strength. Simultaneously, the excellent coordination in the deformation ability between the lamellar αs and β phases is what enables the alloy with a bimodal microstructure to have the most outstanding mechanical properties. Additionally, the presence of a grain boundary α phase and the parallel arrangement of a coarse αs phase are the main reasons for the inferior mechanical properties of the Ti-5111 alloy with a lamellar microstructure. The fracture mechanism of the alloy with an equiaxed microstructure is a mixed fracture mechanism including ductile fracture and destructive fracture. The fracture mechanisms of the Ti-5111 alloy with bimodal and lamellar microstructures are typical ductile fracture and cleavage fracture, respectively. These findings serve as a guide for the performance improvement and application of the Ti-5111 alloy.

Microstructure characteristics of high strength-ductility powder metallurgy superalloy hot oscillatory pressed at sub-solvus temperatures

The early high-strength powder metallurgy superalloys used in aero engine are always prepared by hot isostatic pressing (HIPing) at sub-solvus temperature, but the as-HIPed materials experience prior particle boundaries (PPBs), thus the mechanical ductility is reduced. In order to eliminate the PPBs and obtain high ductility, the samples are fabricated by hot oscillatory pressing (HOPing). Microstructures of the samples are characterized by electron back scattering diffraction (EBSD), scanning electron microscopy (SEM) and so on. The results show that compared with hot pressed (HPed) samples, the HOPed samples present higher density, smaller grain size, lower PPBs scale, and enhanced room temperature tensile properties. The room temperature tensile strength and elongation at break of HOPed sample are 1417 MPa and 32.5 %, respectively, which is obviously better than those of HPed sample (1289 MPa and 20.3 %) and those of HIP sample (1363 MPa and 28.5 %). High strength-ductility is attributed to the accelerated densification and the inhibited PPBs induced by the oscillatory pressure.

Effect of Co-addition of Sn, Traces of RE and Ca on the Mechanical and Micro Structural Properties of As-cast AZ80 Alloy

In this study, the effect of co-addition of tin (0, 6 and 9 wt.%), cerium (0, 0.3 and 0.6 wt.%), gadolinium (0, 0.6 and 0.9 wt.%) and calcium (0, 0.6 and 0.9 wt.%) on the mechanical and microstructural properties of AZ80 magnesium alloy is investigated. The results indicate that the mechanical properties are improved for all the as-cast alloys when compared to base alloy except for one alloy which is due to the presence of Mg-Sn-Ca phase in high volume fraction. Also, it is found that the existence of Al2Ca, Mg2Ca, Al2RE, MgSnRE and Mg2Sn phases have a significant impact on the mechanical and microstructural characteristics of the as-cast AZ80 alloys. It is observed that without the addition of Sn content, the best room temperature tensile properties are obtained for the alloy containing 1.5 wt.% of RE and 0.9 wt.% of Ca. With the addition of Sn, it is found that the best room temperature tensile properties are obtained for the alloy containing 6 wt.% of Sn, 0.9 wt.% of RE and 0.5 wt.% of Ca.

Synergistic influence of cerium and yttrium micro-addition on microstructure and mechanical tensile properties of K465 nickel based superalloy

The microstructures and room temperature tensile properties of a nickel-based cast superalloy K465 were investigated with the cerium (Ce) and cerium + yttrium (Y) additions, respectively. In K465 superalloys, Ce element was found to distribute in the internal grains of K465. And, the Y element was shown to combine towards with the MC carbides. The tensile properties experienced increasement with the addition of Ce and Y, 0.86 % increasement for Ce addition and 8.35 % increasement for Ce + Y addition. The synergistic effect of rare earths element plays a positive role in the mechanical properties of the nickel based superalloy.

Mapping the roles of scan strategy and build orientation in predicting the crystallographic texture and yield strength of 316L stainless steel produced by laser powder bed fusion

Laser Powder Bed Fusion (L-PBF) has emerged as a leading additive manufacturing (AM) technique for manufacturing complex metal parts, with 316L stainless steel being favored for its exceptional corrosion resistance and mechanical properties. While previous studies have explored the effects of different scan strategies and build orientations on the microstructure and room temperature tensile properties of L-PBF printed 316L stainless steel, there is still a lack of a comprehensive predictive model that accurately captures the combined effects of these process parameters on the final crystallographic texture and tensile properties. This study presents a novel approach that establishes a direct correlation between process parameters, microstructure, and mechanical behavior by modeling the influence of scan strategy rotation angles and build orientations on the crystallographic texture of L-PBF-manufactured 316L stainless steel. To validate the model, a series of samples were fabricated using various scan strategy rotation angles and build orientations, enabling detailed microstructural analysis and mechanical testing. The findings demonstrate a direct relationship between the selected process parameters and the resulting mechanical properties, underscoring the importance of scan strategy and build orientation selection on mechanical response. Furthermore, our calibrated model exhibits high predictive accuracy as validated through a comparison with experimental data.

Effect of pre-precipitation thermomechanical treatment on precipitation behavior of CLAM steel

China Low Activation Martensitic steel (CLAM) is a cladding material used in thermonuclear fusion reactors. Its high temperature performance is closely related to precipitation strengthening. The MX phase with strong thermal stability is the key to improving the high temperature performance of CLAM steel, and the M23C6 phase which is easy to coarsen under long-term high temperature service conditions is one of the important factors causing creep failure. In order to increase the content of MX phase and reduce the content of M23C6 phase, this paper first pre-precipitates near the precipitation temperature of M23C6 phase (which is also close to the maximum precipitation temperature of MX phase), which limits the precipitation of M23C6 phase and promotes the maximum precipitation of MX phase. Then the subsequent thermomechanical treatment (TMT) is carried out. The results show that the content of M23C6 phase in the samples after pre-precipitation TMT is greatly reduced, and the size is slightly reduced compared with the samples with only thermal deformation. The size of the MX phase is reduced by 10.6%, the volume density is increased by 88%, the volume fraction is increased by 34.1%, and the dislocation density is slightly increased. At the same time, it was found that a large number of MX phases precipitated at the lath boundary and pinned the boundary, which delayed the coarsening of the lath during tempering. The changes of these microstructures improve the precipitation strengthening, dislocation strengthening and boundary strengthening, so the room temperature tensile properties and high temperature tensile properties are improved, but the work hardening makes the total elongation and room temperature impact properties decrease.

Effect of texture on the room temperature tensile and creep properties of Ti–6Al–4V plate with large thickness

Texture is inevitably generated during the rolling process of titanium alloys, which has a significant impact on mechanical properties. The relationship between microstructure, texture and mechanical properties of the rolled Ti–6Al–4V alloy plate with large thickness was systematically investigated in this study. The texture type varied with the thickness of the plate. The basal pole concentrated in the transverse direction (TD) at the surface of the plate and tilted from TD towards the rolling direction (RD) at the quarter thickness of the plate. For the center of the plate, the basal pole had peaks concentrated close to both TD and RD. Tensile tests indicated that TD samples not only have high strength but also maintain good plasticity compared with RD and the normal direction (ND) samples. The yield anisotropy could be explained by the difficulty of prismatic and basal dislocation slip. The cold creep behavior of the thick plate depended on both Schmid factor of dislocation slip and grain size. Moreover, the strain hardening exponent was positively correlated with cold creep strain. Abundant prismatic <a> and pyramidal <c+a> dislocations were activated, and slip transfer and cross-slip made the dislocation slip distance longer, which contributed to creep strain and thus reduced the creep resistance of ND sample.

Effect of Aging Temperature on Microstructure, Mechanical, and Wear Properties of 18Ni-300 Maraging Steel Produced by Powder Bed Fusion

Additive manufacturing technologies for metallic materials based on powder bed fusion have enormous industrial potential. In this study, we manufactured 18Ni-300 maraging steel using the powder bed fusion (PBF) process and investigated the effects of annealing temperatures of 430 °C, 490 °C, and 550 °C for 3 h on its microstructure, tensile fracture mechanism, and wear properties compared with the as-built specimen. The results show that annealing heat treatment effectively improved the dry sliding friction, wear properties, and room temperature tensile properties compared to the as-built specimen. Compared to other aging-treated samples, specimens that underwent heat treatment in optimal settings had superior properties. With optimal heat treatment, while melt pool boundaries remained, the cellular and columnar structures became finer compared to the un-treated specimens, and the number of dimples decreased. Consequently, the hardness and tensile strength improved by approximately 56.17% and 40.63%, respectively. The 18Ni-300 maraging steel sample that underwent heat treatment at optimal settings exhibited a coefficient of friction approximately 33.33% lower than the as-built alloy.

Corrosion resistance of 9–12Cr ODS steels in pressurized water for fusion application

The blanket design of Chinese fusion engineering test reactor (CFETR) may utilize pressurized water as coolant. The fusion structural materials will endure high temperature, high pressure and result in corrosion in the pressurized water. It is necessary to verify corrosion resistance of the materials. In the present study, three kinds of advanced fusion structural materials with excellent mechanical properties and neutron irradiation resistance, i.e., 9Cr-ODS steel, 9CrODS-Al steel, and 12CrODS-Al steel were immersed in pressurized water at 325 °C under the pressure of 15.5 MPa up to 859 h. Room-temperature tensile properties were investigated for the materials before and after corrosion. The oxidation layers of the steels were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ODS steels have good corrosion resistance in the pressurized water, especially the 9CrODS-Al and 12CrODS-Al steels. The outer oxide layer is identified as Fe2O3 for all the steels. The inner layer is mainly FeCr2O4 for the 9CrODS steel, and Fe(Al,Cr)2O4 for the ODS steels with Al element which better protect the steels from further corrosion. The relevant properties data can provide reference for the blanket materials choice of CFETR and the future fusion reactors.

Effect of Mn/Ag Ratio on Microstructure and Mechanical Properties of Heat-Resistant Al-Cu Alloys.

This paper mainly investigated the effect of the Mn/Ag ratio on the microstructure and room temperature and high-temperature (350 °C) tensile mechanical properties of the as-cast and heat-treated Al-6Cu-xMn-yAg (x + y = 0.8, wt.%) alloys. The as-cast alloy has α-Al, Al2Cu, and a small amount of Al7Cu2 (Fe, Mn) and Al20Cu2 (Mn, Fe)3 phases. After T6 heat treatment, a massive dispersive and fine θ'-Al2Cu phase (100~400 nm) is precipitated from the matrix. The Mn/Ag ratio influences the quantity and size of the precipitates; when the Mn/Ag ratio is 1:1, the θ'-Al2Cu precipitation quantity reaches the highest and smallest. Compared with the as-cast alloy, the tensile strength of the heat-treated alloy at room temperature and high temperature is greatly improved. The strengthening effect of the alloy is mainly attributed to the nanoparticles precipitated from the matrix. The Mn/Ag ratio also affects the high-temperature tensile mechanical properties of the alloy. The high-temperature tensile strength of the alloy with a 1:1 Mn/Ag ratio is the highest, reaching 135.89 MPa, 42.95% higher than that of the as-cast alloy. The analysis shows that a synergistic effect between Mn and Ag elements can promote the precipitation and refinement of the θ'-Al2Cu phase, and there is an optimal ratio (1:1) that obtains the lowest interfacial energy for co-segregation of Mn and Ag at the θ'/Al interface that makes θ'-Al2Cu have the best resistance to coarsening.

Effect of Impurities on the Compatibility of Steels in Supercritical CO2 at 450°–650°C

Abstract Direct-fired supercritical CO2 (sCO2) power cycles are a pathway to low-CO2 fossil energy but contain O2 and H2O in the sCO2 from combustion. The effect of impurities on structural steels was investigated at 450°–650 °C in 30 MPa sCO2. The test matrix included 9 and 12%Cr ferritic-martensitic (FM) steels and conventional and advanced austenitic steels exposed for 1000–2000 h with and without additions of 1%O2 and 0.1%H2O to simulate the cycle after water removal. For FM steels, the mass gains and scale thicknesses were similar with and without impurities with the formation of thick, duplex Fe-rich scales in all cases including the observation that Fe2O3 only formed with 1%O2. For the austenitic steels, higher mass gains were observed at all temperatures with increased formation of Fe-rich oxides when impurities were added. Carbon ingress was assessed by bulk combustion analysis, glow discharge optical emission spectroscopy (GDOES) and measuring postexposure room temperature tensile properties. Bulk C content was strongly increased at 650 °C but not at 450° or 550 °C.

The microstructure effects on irradiation response of ferritic – martensitic steels

Microstructural optimization to achieve greater mechanical strength has been one of the focuses in ferritic–martensitic steels development. However, these optimized microstructures’ effects on the radiation response are not well known. In this work, two ferritic–martensitic steels (9Cr-NbMo and 9Cr-Ta) underwent neutron irradiation in the High Flux Isotope Reactor, and their room-temperature post-irradiation tensile properties and microstructure evolutions were investigated and compared. These two steels exhibit similar pre-irradiation tensile behavior, and their yield strengths are higher than that of other ferritic–martensitic steels by about 200–250 MPa. Microstructural characterization on pre-irradiated materials reveals a smaller grain size in 9Cr-Ta (2.8 ± 0.3 μm in 9Cr-Ta versus 4.3 ± 0.5 μm in 9Cr-NbMo) but higher dislocation density and precipitate density in 9Cr-NbMo. As is common for ferritic–martensitic steels at low irradiation temperatures (less than about 0.45Tm), irradiation-induced hardening at 400 °C was observed for both alloys. Irradiation at 490 °C causes the two alloys to exhibit different tensile behavior: 9Cr-Ta softens by 208 MPa in yield stress, whereas 9Cr-NbMo maintains strength. Microstructural characterizations were performed, including precipitate growth, dislocation, and defect formation. Using the barrier hardening model for microstructure–property correlation, the softening in irradiated 9Cr-Ta is primarily attributed to the significant dislocation recovery, while the strength lost from the slight dislocation recovery in 9Cr-NbMo was compensated by the additional strength from the irradiation-induced cavities. The microstructure effect (primarily precipitate, dislocation and boundary) on the radiation response is discussed herein.

Influence of Various Heat Treatments on Microstructures and Mechanical Properties of GH4099 Superalloy Produced by Laser Powder Bed Fusion.

The microstructures and mechanical properties of a γ'-strengthened nickel-based superalloy, GH4099, produced by laser powder bed fusion, at room temperature and 900 °C are investigated, followed by three various heat treatments. The as-built (AB) alloy consists of cellular/dendrite substructures within columnar grains aligning in <100> crystal orientation. No γ' phase is observed in the AB sample due to the relatively low content of Al +Ti. Following the standard solid solution treatment, the molten pool boundaries and cellular/dendrite substructures disappear, whilst the columnar grains remain. The transformation of columnar grains to equiaxed grains occurs through the primary solid solution treatment due to the recovery and recrystallization process. After aging at 850 °C for 480 min, the carbides in the three samples distributed at grain boundaries and within grains and the spherical γ' phase whose size is about 43 nm ± 16 nm develop in the standard solid solution + aging and primary solid solution + aging samples (SA and PA samples) while the bimodal size of cubic (181 nm ± 85 nm) and spherical (43 nm ± 16 nm) γ' precipitates is presented in the primary solid solution + secondary solid solution + aging sample (PSA samples). The uniaxial tensile tests are carried out at room temperature (RT) and 900 °C. The AB sample has the best RT ductility (~51% of elongation and ~67% of area reduction). Following the three heat treatments, the samples all acquire excellent RT tensile properties (>750 MPa of yield strengths and >32% of elongations). However, clear ductility dips and intergranular fracture modes occur during the 900 °C tensile tests, which could be related to carbide distribution and a change in the deformation mechanism.

Study on the Forming Process and Properties of AlSi60 Alloy by Selective Laser Melting

Hypereutectic Al-Si alloys, which have a silicon content ranging from 12% to 70%, are a new generation of casing materials for chip packaging. They have broad applications in aerospace, weaponry, and civilian communications. Selective Laser Melting (SLM) offers significant advantages in achieving near-net shaping of complex casings. This paper presents a study on the formation defects, microstructure, and room temperature tensile properties of AlSi60 alloy prepared by SLM. The results indicate that the primary forming defects in the SLM AlSi60 alloy are balling, lack of fusion, and porosity. These defects are mainly influenced by the volumetric energy density. Samples of good quality can be produced within the range of 150 J/mm3 to 250 J/mm3. However, the same volumetric energy density can result in differences in sample quality due to various combinations of process parameters. Therefore, it has been determined that a well-formed AlSi60 alloy can be obtained within a laser power range of 300 W–350 W, scanning speed of 400 mm/s–800 mm/s, and hatch spacing of 0.09 mm–0.13 mm, with a density close to 98%. The microstructure of the SLM AlSi60 alloy consists of primary Si phases with irregular shapes and sharp edges measuring 5–10 μm, eutectic Si particles of 0.5 μm, and α-Al phases, with eutectic Si dispersed within the α-Al. The SLM AlSi60 alloy exhibits fine and evenly distributed primary Si phases with an average hardness of 203 HV. No significant anisotropy in hardness values was observed in the X and Y directions. The tensile strength of the alloy reached an average of 219 MPa, with an average elongation of 2.99%. During the tensile process, cracks initiated by the primary Si phases rapidly expanded, exhibiting minor ductile fracture characteristics in the Al phases. Due to the high volume fraction of Si phases, the tensile test was dominated by brittle fracture. The tensile curve only exhibited the elastic stage.

Evaluation of coated steels in supercritical CO2

AbstractThe carburizing supercritical CO2 (sCO2) environment limits the use of lower cost steels in the lower temperature (450–650°C) portions of the sCO2 Brayton cycle because of concerns about internal carburization and embrittlement. Results on a ferritic–martensitic steel and conventional and advanced austenitic steels at 450–650°C in 30 MPa sCO2 with and without 1% O2 and 0.1% H2O additions have indicated that sCO2 environments will have lower maximum operating temperatures compared to steam plants. Pack Al and Cr coatings were evaluated at 650°C on T91 and 316H substrates and showed some benefit for up to 2000 h at 650°C, especially without impurities. However, characterization indicated Al2O3 was not formed and Cr‐rich carbides formed in the Cr coatings. With the addition of impurities in the sCO2, the coatings were less protective at 650°C. Subsequent exposures at 600°C in sCO2 showed similar behavior. Postexposure evaluations included measuring the bulk C content and room temperature tensile properties. Improvements were indicated but the tensile results were complicated by the high temperature pack coating process affecting the substrate properties.

Effect of Al−10Nb−3Ce−2.5B inoculant on microstructures, damping and tensile mechanical properties of Zn−Al eutectoid alloy

A novel Al−10Nb−3Ce−2.5B inoculant was prepared, and its effect on microstructures, damping and tensile mechanical properties of Zn−Al eutectoid (ZA22) alloy was systematically studied. It was found that the inoculant had an effective refining effect on the α-phase in the ZA22 alloy (α-phase could be refined to 16 μm), and the morphology of the α-phase could also change from coarse dendrite to small petal. Orientation relationships (ORs) between the α-phase and the CeB6 and NbB2 particles in the inoculant were established by the edge−edge matching model (E2EM), and based on the E2EM, the refining mechanism of the inoculant on the ZA22 alloy was revealed. Compared with the uninoculated ZA22 alloy, the high temperature damping of the inoculated ZA22 alloy, especially the damping peak arising from the reverse eutectoid transformation, was significantly improved. Moreover, the room temperature tensile mechanical properties of the inoculated ZA22 alloy were also significantly improved. The tensile strength and elongation of the ZA22 alloy with the best refining effect were 18.56% and 119.04% higher than those of the unrefined ZA22 alloy, respectively. Correlated mechanisms were discussed.

Microstructures and mechanical properties of a γ-TiAl alloy modified by Gd additions

The microstructural evolutions and room-temperature tensile properties of Ti-45Al-2.5Nb-1.5Mo-(0-0.2)Gd were investigated in details. Experimental result revealed that there were precipitated particles, involving Gd2TiO5 and GdAl3, distributing within the microstructure of the Gd-containing TiAl alloys, and the increase in the Gd addition resulted in the aggregation of Gd-containing particles, forming a network structure along grain boundary and colony boundary. The addition of Gd also had a significant refining effect on the average inter-lamellar spacing. The ultimate/yield strength and elongation increased first and then decreased with the content of Gd. Gd addition did not change the mixed fracture mode of crack propagation along and across the lamellae. In the plastic deformation process of Gd-containing sample, except for dislocation gliding, twinning-controlled deformation mode occurred, contributing to the improvement of mechanical properties. Moreover, dislocations could directly cut through the small-size Gd-containing particle, while some dislocations would continue to slip via bypassing the large-size Gd-containing particle.