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In recent years, high entropy alloy (HEA) matrix composites have undergone rapid development. In this work, the effects of different WC contents (10 wt.%, 20 wt.%, and 30 wt.%) on the microstructure, mechanical properties, and wear resistance of FeCoCrNi HEA matrix composites prepared by spark plasma sintering (SPS) were studied. The results show that the WC–HEA composites are mainly composed of an FCC matrix phase (Ni, Fe) and carbide phases (Cr7C3, Co3W3C, WC, etc.). The hardness of the 30 WC–HEA composites was the highest at 459.2 HV, which is 71.2% higher than the 268.3 HV of the pure matrix material. Similarly, the compressive yield strength of the 30 WC–HEA composite was the largest, reaching 1315.1 MPa, which is 112.1% higher than that of the pure matrix material. However, the compression deformation rate of the 30 WC–HEA composite significantly decreased to 16.6%. Under the same dry friction conditions, the addition of an appropriate amount of WC particles can reduce the friction coefficient of the HEA matrix. The wear volume of the composites decreased rapidly with the increase of WC content. The wear volume of 30 WC–HEA was the lowest, only 3.17% of that of the pure matrix material. [ABSTRACT FROM AUTHOR]

Chemical furnace ash was generated during the use of pernicious metal alloy catalytic net, which has high recovery value. Because of the ash contains organic matter and oxidized stateRhodium, it difficult to dissolve. In this paper, hydrogen was reduced after ignition, and hydrochloric acid-hydrogen peroxide solution was used for airtight digestion, the obtained solution was determined by ICP-AES. For Chemical catalytic furnace ash with Rhodium concentration rage of 0.01%~5.0%, the relative standard deviation (RSD) was less than 2% (n=7), and the recovery was 95.50%~104.46%. The result were in agreement with the nominal values of quality control sample, meeting the requirement for recycling trade. [ABSTRACT FROM AUTHOR]

Au-Pt alloy has been widely used in the aviation field as verification quality with high density, high hardness, good electrical and thermal conductivity, ultra-low residual magnetic moment and magnetic susceptibility. But there is a very serious component segregation phenomenon in the preparation process of Au-Pt alloy. This paper is mainly based on this research, high frequency induction furnace and spray casting two processes are used to prepare Au-Pt alloy samples, then the distribution state of component segregation of Au-Pt alloy is studied by multi-pass rolling combined with solution process, the results show that the high frequency induction furnace prepared Au-Pt alloy composition segregation is more serious and the spraying process successfully realizes the regulation of Au-Pt alloy component segregation. Through EDS energy spectrum analysis, it is found that the composition deviation of the spraying process can be controlled from 20% to 1% compared with the induction melting process. Subsequently, the Anasys fluent calculation simulation is used to obtain the temperature, flow and solute field distribution during the solidification process under two different preparation processes of Au-Pt alloy. [ABSTRACT FROM AUTHOR]

An equiatomic CrCoNi medium-entropy alloy was subjected to high-energy shot peening (HESP) to fabricate a gradient nanostructure (GNS) in this work. The microstructures of the GNS samples at different depths within the deformed layer were thoroughly investigated. The microstructure exhibited a transformation from unstressed coarse grains to deformed coarse grains, followed by the formation of ultrafine grains, and ultimately reaching a final nanocrystalline structure with a uniform size of approximately 50 nm. Detailed structural analysis indicated that the deformation process was primarily influenced by the interaction between dislocations and deformation twins, which was attributed to the low stacking fault energy (SFE) of the alloy. The nanocrystalline mechanism was divided into three stages. In the coarse-grained deformation stage, the dislocation band divided twin/matrix lamellae into sub-segments, and the cross twin divided coarse grains into ultrafine grains simultaneously. In the ultrafine grain deformation stage, dislocations were arranged around the deformation twins in order to break the twins to form incoherent boundaries, destroying the coherent relationship between the twin and matrix. Finally, in the nanocrystalline deformation stage, the nanocrystalline structure was further divided into smaller segments to accommodate additional strains through the interaction between dislocations and twins. [ABSTRACT FROM AUTHOR]

Long-term thermal stability plays an important role in practical applications of Al-Zn-Mg-Cu alloys. In the present work, thermal stability of the T7452-treated 7085 Al alloy was assessed at temperatures of 100, 125, 150 and 175 °C for 100, 500 and 1000 h, through hardness, electrical conductivity and tensile tests after thermal exposure. The nanoscale precipitates under different thermal exposure conditions were also qualitatively studied by transmission electron microscopy (TEM). The results show that thermal stability of the alloy is more sensitive to thermal exposure temperature than to exposure time. The hardness increases first and then decreases with the increase of exposure temperature while it decreases gradually as exposure time prolongs. However, the variation of electrical conductivity is opposite. The tensile strength, yield strength and hardness after 100 °C/100 h thermal exposure increased by 2.4%, 6.7% and 9.2% than those of the alloy without thermal exposure, respectively. The precipitate sequence during thermal exposure is coincident with that of aging. In addition, as thermal exposure deepens, the average radius of precipitates increases while the volume fraction decreases. Meanwhile, the grain boundary precipitates coarsen and transform from continuous to discrete. The influence of precipitates on properties of the alloy is discussed quantitatively. • Thermal stability of 7085 alloy was conducted under different temperatures for different durations. • Correlations between hardness and electrical conductivity of the 7085 alloy during thermal exposure were investigated. • Thermal exposure temperature played more significant effect on strength and electrical conductivity than the exposure time. • The average precipitate size increased while the volume fraction decreased as thermal exposure deepened. • The increments of yield strength before and after thermal exposure were calculated. [ABSTRACT FROM AUTHOR]

[Display omitted] • γ′′ precipitation behaviors and their impacts on mechanical properties were systematically investigated. • The strengthening and deformation mechanical in Nb-alloyed MEA with different microstructures were investigated. • The heterogeneous lamellar grain coupling with dual-precipitation structure in this Nb-alloyed MEA brought out superior strength-ductility synergy properties. In present work, a novel γ′′-strengthened Nb-alloyed medium-entropy alloy (MEA) was successfully fabricated and systematically investigated. Our results evidence that the γ′′ phase brings out significant precipitation hardening effect (∼10.2 %volume fraction contributes ∼ 685 MPa strength enhancement). The metastable γ′′ phase could abnormally transform to ε phase, and the morphology and distribution of ε phase shows great impacts on mechanical properties. A hetero-lamellae grain coupling with dual-precipitation (HLG + dual-P) structure was successfully constructed in this Nb-alloyed MEA, which could effectively combine precipitation hardening and hetero-deformation induced (HDI) hardening effects. Deformation characters investigations reveals that the absence of mechanical twinning in γ′′-strengthened MEA originates from the improved critical twinning stress related to the fine dislocation source size and the difficulty of high-energy complex SFs reordering. The combination of massive stacking-faults, Lomer-Cottrell locks and dynamically reinforced HDI hardening contribute to the excellent ductility and work-hardening capacity at high-level strength in the HLG + dual-P structural alloy. Our work provides a useful insight and helpful guidance for developing high-performance precipitation-hardened multi-principal element alloys. [ABSTRACT FROM AUTHOR]

The outstanding thermal stability of coherent γ′ phases at 1073 K in Ni 46 Cr 23 Fe 23 Al 4 Ti 4 and Ni 46 Cr 23 Co 23 Al 4 Ti 4 medium-entropy alloys were systematically investigated. The coarsening behaviors of coherent γ′ phase in the investigated alloys follow the classical Lifshitz-Slyozov-Wagner (LSW) model. The γ/γ′ lattice misfit plays an important role in the morphology evolution and coarsening behavior of γ′ phase. The lower γ/γ′ lattice misfit helps to maintain the spherical morphology of γ′ phase and leads to a lower γ/γ′ interfacial energy. The small γ/γ′ lattice misfit (0.087%) and interfacial energy (1.73 mJ/m2) in Ni 46 Cr 23 Fe 23 Al 4 Ti 4 alloy result in the sluggish coarsening behavior of coherent γ′ phase. Reducing γ/γ′ lattice misfit and decreasing interfacial energy should be effective strategies for developing γ′-strengthened high/medium-entropy alloys for high-temperature application. [Display omitted] [ABSTRACT FROM AUTHOR]

The release of pollutants from bacterial pathogens in air or water, which causes a serious threat to human health and well-being. Traditional antibiotics have exhibited insufficient ability in combating bacteria owing to the emergence of drug-resistant bacteria. Hence, effective antibacterial candidates urgently need to be explored as an alternative for overcoming the antibiotic barrier. It is highly necessary to find an effective stable disinfection system with the nature of environmental-friendly, high activity and stability, convenient synthesis procedure, low energy, cleaner, and low economic consumption. Considering these aspects, optical strategy and chemical treatment bring convenience and advantages in bacterial inactivation. In this work, the bimetallic Cu–Bi alloy was explored using a simple one-pot solvothermal strategy. On the one hand, the bimetallic structure can prevent copper from oxidation to decrease potential secondary pollution activity caused by excessive release of copper ions, and maintain copper's highly biological activity. On the other hand, the as-prepared Cu–Bi alloy was employed to perform antibacterial applications. Hyperthermia is driven by near-infrared light and the introduction of ROS from Cu Fenton-like reaction that can effectively promote the death of bacteria, and perform a better antibacterial ability than that of single Ag + or Cu2+ release, resulting in the significant growth inhibition of E. coli. Overall, the combination of the multiple disinfection ability of the Cu–Bi alloy, involving highly efficient ROS generation and effective photothermal performance, not only shows the potential in fighting against pathogenic bacteria but also provides an important insight for the exploration of antibacterial platforms based on the bimetallic materials. • The stabilized bimetallic Cu-Bi alloy is briefly designed using solvothermal method for application in cleaner production. • The Cu–Bi combined the advantages of bismuth and copper activity. • The closed-circuit loop of the Cu–Bi alloy to perform a satisfying photothermal phenomenon. • The Cu–Bi alloy exhibited good synergistic functions in photothermal and chemical antibacterial strategy. • The Cu–Bi alloy operated a better bactericidal performance than Ag+ and Cu+. [ABSTRACT FROM AUTHOR]

The requirement for 7085 Al alloy as large airframe parts has been increasing due to its low quenching sensitivity and high strength. However, the relationship between high temperature mechanical properties and the evolution of precipitates in hot environments is still unclear. In this work, thermal exposure followed by tensile tests were conducted on the 7085 Al alloy at various temperatures (100 °C, 125 °C, 150 °C and 175 °C). Variations of hardness, electrical conductivity and tensile properties were investigated. The evolution of the nano scale precipitates was also quantitatively characterized by transmission electron microscopy (TEM). The results show that the hardness and electrical conductivity of the alloy are more sensitive to the temperature than to the time. The strength decreases continuously with the increase of temperature due to the transformation from η′ to η phase during the process. Furthermore, the main η phase in the alloy transformed from V3 and V4 to V1 and V2 variants when the temperature was 125 °C. Additionally, with increasing the temperature, the average precipitate radius increased, meanwhile the volume fraction and number density of the precipitates decreased. The strengthening effect of nano scale precipitates on tensile properties of the alloy was calculated and analyzed. [ABSTRACT FROM AUTHOR]

In this work, a novel non-equiamotic Ni 47.5 Cr 23.75 Co 23.75 Ti 5 medium-entropy alloy strengthened by heterogeneous precipitates was successfully fabricated. Our results demonstrate heterogeneous precipitation behaviors, i.e. nanosized spherical particles with L1 2 superlattice in inner grains plus nano-lamellar precipitates with long-period stacking ordered structure nearby grain boundaries, could bring out outstanding strength-ductility synergy properties. This heterogeneous precipitation-strengthened medium-entropy alloy exhibits high yield strength and ultimate tensile strength of ~840 MPa and ~1220 MPa, respectively, and remains an excellent ductility of ~34.8%. Further analyses indicate this heterogeneous precipitation result in effective precipitation-strengthening enhancement (~603 MPa), stacking-faults activated in spherical precipitates region and deformation nanotwins induced in lamellar precipitates region synergy contribute to high work-hardening capacity and ductility. Our work provides not only a useful insight of precipitation behaviors caused by Ti element addition in non-equiatomic high/medium-entropy alloys, but also a further understanding of precipitation-strengthening in high/medium-entropy alloys. A novel Ni 47.5 Cr 23.75 Co 23.75 Ti 5 MEA strengthened by heterogeneous precipitates was investigated. The heterogeneous precipitates bring out significant yield strength enhancement (~603 MPa). Stacking-faultsand deformation nanotwins synergy contributing to the high work-hardening capacity and ductility. [ABSTRACT FROM AUTHOR]

In this work, we mainly focused on single phase face-centered cubic (FCC) type CrCoNi medium-entropy alloy (MEA), fabricated the homogeneous and heterogeneous grain structure through heavily deformation and subsequent annealing treatment, then investigated the Hall-petch relationship and heterogeneous strength of CrCoNi MEA. The experimental results show that, the large friction stress of fully-recrystallized CrCoNi MEA resulted from the severe lattice distortion, short-time partial-recrystallized annealing and abundant thermal twinning facilitated the heterogeneous structure with multiple gain size. The heterogeneous structure (i.e. partial-recrystallized structure) exhibited a superb strength-ductility synergy in comparison with nano-grained structure and/or ultrafine-grained structure in CrCoNi MEA. The results would provide the comprehensive understanding of CrCoNi MEA, as well as the essentials for further development and applications of FCC type multicomponent alloys. • The Hall-petch relationship of CoCrNi MEA was investigated. • The heterogeneous structures were successfully fabricated through partial-recrystallized annealing. • The detailed recrystallization behavior and mechanical properties evolution were investigated. [ABSTRACT FROM AUTHOR]

In this work, we report a novel Co-free non-equiatomic Ni 57.6 Cr 19.2 Fe 19.2 Nb 4 medium-entropy alloy (MEA) with outstanding tensile properties. We systematically investigate its microstructure, strengthening and deformation mechanisms combined by XRD, EBSD and TEM investigations. Experimental results demonstrate this Co-free MEA strengthened by nanosized coherent D0 22 - (Ni, Cr, Fe) 3 (Nb, Fe)-type precipitate (γ′′ phase) with disk shape. This γ′′-precipitation strengthened MEA exhibits the outstanding strength-ductility synergy, showing a high yield strength of ∼960 MPa, tensile strength of ∼1320 MPa and an excellent ductility of ∼34%. The nanosized γ′′ phases bought out effective precipitation strengthening in this Co-free MEA, contributing a majority yield strength enhancement of ∼660 MPa. For this γ′′-precipitation strengthened MEA, the dominant deformation model was the stacking-faults controlled mode, which resulted in a slight ductility sacrifice, in comparison with the solid solution treated MEA. Our work provides solid foundations for further development of high performance Co-free MEAs/(high-entropy alloys) HEAs. Image 1 • A novel Co-free Ni 57.6 Cr 19.2 Fe 19.2 Nb 4 MEA strengthened by γ′′ phase was introduced. • Nanosized γ′′ phase exhibited signification precipitation strength. • The strength and deformation mechanism of this precipitation-strengthened MEA were investigated. [ABSTRACT FROM AUTHOR]

In this work, a novel non-equiamotic Ni 46 Cr 23 Co 23 Al 4 Ti 4 medium-entropy alloy (MEA) strengthened by nanoscale coherent γ′ particles with L1 2 superlattice was successfully synthesized, then its microstructure, mechanical properties, strengthening and deformation mechanism were systemically investigated. Our experimental results demonstrated that this precipitation strengthened MEA exhibited outstanding strength-ductility synergy, combination a high yield strength of ~920 MPa, an ultimate tensile strength of ~1320 MPa and an excellent ductility of ~36%. The nanosized γ′ particles bought out effective precipitation strengthening in this non-equiamotic MEA, contributing a majority yield strength enhancement of ~600 MPa. For this γ′-strengthened MEA, the dominant deformation model was the stacking-faults controlled mode rather than the mechanical twin dominated mode in single-phase face-centered-cubic structure Ni 50 Cr 25 Co 25 MEA. Our work provides a further understanding of precipitate strengthening in non-equiamotic high-entropy alloys (HEAs)/MEAs. • Microstructure and mechanical properties of Ni 46 Cr 23 Co 23 Al 4 Ti 4 were investigated. • The aged Ni 46 Cr 23 Co 23 Al 4 Ti 4 showing outstanding strength-ductility synergy. • The strength and deformation mechanisms of aged Ni 46 Cr 23 Co 23 Al 4 Ti 4 were investigated. [ABSTRACT FROM AUTHOR]

In this study, we synthesized a series of (CoCrNi) 100-x Al x (x = 0–30 at.%) medium-entropy alloys (MEAs), investigated alloying effects of Al element on microstructure and mechanical properties of CrCoNi MEA, then analyzed the strengthen mechanism caused by Al element. Microstructural evolutions were evaluated by means of X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The microstructures of (CoCrNi) 100-x Al x MEAs evolved from single face-centered cubic (FCC) (x < 12 at.%), to duplex FCC plus body-centered cubic (BCC) (12 ≤ x < 22 at.%), then to double BCC (x ≥ 22 at.%) structures with Al content increase. When Al content increase to 16 at.%, BCC phase decomposed into plate-like intervened structure with ordered and disordered BCC phases (B2 and A2 structure) by spinodal decomposition mechanism. When Al content higher than 22 at.%, spinodal structure evolve from plate-like intervened structure to spherical particles dispersed in matrix structure. The hardness of Al x alloys increased from HV170 to the maximum of HV700 and the compressive yield strength rose form 204 MPa–1792 MPa. The solid-solution strengthening of Al element and formation of hard BCC phase were the two main factors contributing to the strengthening effect in this alloy system. Experimental results showed that the duplex FCC plus BCC structure can significant enhanced the strength-ductility synergy of CrCoNi MEA. It is especially noted that Al 19 alloy which consist of 40% volume fraction FCC and 60% volume fraction BCC exhibits the most attractive properties accompany with compromise compressive yield strength, fracture strength and facture strain of 1226 MPa, 2542 MPa and 21.97%, respectively, and the corresponding hardness of 494 HV. • Structure and mechanical properties evolutions of (CrCoNi) 100-x Al x alloy system were investigated. • (CrCoNi) 100-x Al x alloy system evolved from FCC, to FCC + BCC, then to double BCC structure with Al content increases. • The dual-phase structure can significant enhanced the strength-ductility synergy of CrCoNi MEA. [ABSTRACT FROM AUTHOR]

In present work, the superior high-temperature properties in a novel (Ni, Cr, Fe) 3 (Al, Ti, Cr)-γʹ (L1 2) type precipitation-strengthened Co-free medium-entropy alloy (MEA) was systematically evaluated. Experimental results indicate that this γʹ-strengthened alloy demonstrates excellent structure thermal stability and no other brittle intermetallic phases formed at grain boundaries or grain interior during long-term thermal exposures. The γʹ phase in this Co-free MEA exhibits an extraordinary sluggish coarsening rate, which is much lower than most conventional superalloys and recently developing γʹ-strengthened high/medium-entropy alloys (HEAs/MEAs). This γʹ-strengthened alloy also exhibits a good combination of high γʹ-solvus temperature (1068 °C) and low mass density (7.79 g/cm3). More significantly, this γʹ-strengthened MEA shows excellent high-temperature tensile strength, especially outstanding specific strength, which is superior to most Ni/Co-based superalloys. Our present work provides a useful illustration for designing advanced high-temperature alloys based on γʹ(L1 2)-strengthened HEAs/MEAs, rather than Ni-based/Co-based superalloys. [Display omitted] • A γʹ (L1 2)-strengthened Co-free MEA with superior high-temperature performance was developed. • The γʹ phase in this Co-free MEA exhibits an extraordinary sluggish coarsening rate. • The γʹ-strengthened MEA shows superior high-temperature tensile strength than Ni/Co-based superalloys. [ABSTRACT FROM AUTHOR]

The Ni–Cr–W based Haynes 230 alloy, is considered to have important applications in the hot-end components of aerospace engines due to its excellent high-temperature properties and oxidation resistance. However, Haynes 230 alloy presents a high hot-cracking tendency during the laser powder bed fusion (LPBF) process. In this study, a novel composition optimized Ni–Cr–W superalloy based on Haynes 230 alloy was fabricated by the LPBF method. The metallurgical defects, microstructure and tensile properties at room temperature (RT) of the LPBF Ni–Cr–W based superalloy printed under different volume energy densities (VEDs) were systematically researched. The results show that the novel Ni–Cr–W superalloy presents excellent processability, and a near-fully dense specimen without any metallurgical defects was obtained under optimal VED of 83.33 J/mm3. However, solidification cracks also occurred in the samples with higher VEDs (exceeding 100 J/mm3). The main reason is the increase of thermal stress and liquid-feeding resistance as VED increases. The rapid scanning speed and steep temperature gradient during the LPBF lead to the occurrence of the multi-scale heterogeneous microstructures, including the epitaxial columnar grains with a mixing of {100} and {110} crystallographic alignment along the building direction (BD) and cellular substructures entangled with high-density dislocation. The cellular substructure strengthening and solution strengthening are the dominant factors for the excellent ultimate tensile strength (1100 MPa), yield strength (850 MPa), and ductility (29.3%) of the LPBF alloy at RT. With the increase of VED, the yield strength of the LPBF alloy decreases. The main reason is the reduction of cellular substructure strengthening. The ultimate tensile strength of the LPBF alloy at 1000 °C reaches 200 MPa, which is superior to that of the LPBF Haynes 230. • A novel Ni–Cr–W based superalloy without metallurgical defects was obtained under VED of 83.33 J/mm3. • Solidification cracks occurredwhen VED exceeded 100 J/mm3 due to the increase of thermal stress and liquid-feeding resistance. • The nearly-fully dense sample fabricated under VED of 83.33 J/mm3 realized an excellent strength-ductility balance with the tensile strength of 1100 MPa, yield strength of 850 MPa and elongation of 29.3%. • The yield strength of the alloy decreased with the increase of VED mainly due to the weakened cellular substructure strengthening. [ABSTRACT FROM AUTHOR]

In present work, we investigate the elemental partition behaviors in L1 2 ordered intermetallics and its influence on mechanical properties in a Ni-Co-Cr-Al-Ta medium-entropy alloy (MEA) system through a combination of density functional theory (DFT) calculations and experimental investigation. Our finding reveal that Ta has a strong tendency to occupy Al sublattice, while Co prefers Ni sublattice, Cr, on the other hand, randomly occupy Al and Ni sublattices, resulting in the formation of the multicomponent (Ni, Co, Cr) 3 (Al, Ta, Cr) L1 2 intermetallics. Among the constituent elements, Ta is identified as an efficient element for enhancing hardening of the alloy. Furthermore, we demonstrate that improving Ta/Al ratio leads to a significant increase in anti-phase boundary (APB) energy, resulting in superior precipitation hardening effects and excellent mechanical properties. Our founding provide valuable insights for further the rationally design and rapid development of high performance L1 2 -strengthened alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The heterogeneous nucleation and growth of precipitates at dislocations in Al–Cu–Mg alloy were investigated by examining sample aged at 195°C for various times from 10min to 9h. High resolution transmission electron microscopy (HRTEM) observations and electron energy loss spectrometers (EELS) analysis show that the precipitation sequence of the S (Al2CuMg) phase along dislocations should be SSS→GPB zones→S (Type I)→S (Type I)+S (Type II). Type II S precipitate can nucleate and grow separately at some dislocation parts which are unfavorable for Type I S precipitate formation, or can transit from Type I S precipitate during lateral growth along dislocations by means of continuous or stepped changing in lattice orientations. Both of these modes are accomplished under the action of dislocation strain field. The deviation extent of Type II S precipitate is considered not changing with time but closely related with the interactions between the transformation strain during nucleation and the dislocation strain field. [Copyright &y& Elsevier]

Although deformation processes in single-phase nano-polycrystalline alloys at different temperatures are well described, the deformation mechanism in two-phase nano-polycrystalline alloys at different temperatures is still unclear. Here, the deformation behaviour of the two-phase TiAl+Ti 3 Al nano-polycrystalline alloys is investigated at different temperatures by molecular dynamic simulation. For a comprehensive understanding of the processes, mechanical properties of the single-phase TiAl and Ti 3 Al nano-polycrystalline alloys are explored as well. The results of numerical simulations indicate that temperature has a strong influence on the deformation mechanism of the alloys. When temperature is below 800 K, the critical grain size (~8.3 nm) becomes a dominant factor controlling the deformation process in the single-phase TiAl. In the two-phase TiAl+Ti 3 Al nano-polycrystalline alloys, the motion of dislocations in the TiAl phase with the grain size smaller than the critical size dominates the deformation process. On the other hand, no obvious phenomena linked with the critical size occur in the Ti 3 Al phase. Once the strain exceeds 18.0%, the dislocation emission is observed in the Ti 3 Al grains. At high temperatures (≥800 K), in the two-phase nano-polycrystalline alloy, the deformation mechanism changes from the plastic deformation to the boundary slip and recrystallization. Unlabelled Image • Deformation behaviour of two-phase TiAl+Ti 3 Al nanopolycrystalline alloys is described using molecular dynamic simulations. • The displacement of dislocations in TiAl grains smaller than ~ 8.3 nm dominates the deformation processes below 800 K. • The deformation mechanism changes from the plastic deformation (< 800 K) to the boundary slip and recrystallization at 800 K. [ABSTRACT FROM AUTHOR]