Tensile Deformation Mechanisms Research Articles

Enhancing the strength–ductility synergy of medium-Mn steel by introducing multiple gradient structures

In this study, novel multiple gradient structures with various distributions of austenite/martensite phase, grain sizes, and dislocation densities were fabricated in medium-Mn steel by using torsion treatment, and the corresponding tensile properties and deformation mechanisms were investigated. The results showed that the yield strength and the total elongation of the multiple-gradient-structured samples increased by 27% and 25%, respectively, compared with their homogeneous counterparts. A distinct phase transformation behavior was observed in the present gradient medium-Mn steel. That is, the strain-induced martensitic transformation was promoted in the center during the entire tensile deformation process; however, it was suppressed at the surface during the initial deformation stage and then significantly triggered during the remaining deformation process. Moreover, active strain partitioning at the macroscale and microscale occurred during plastic deformation, which led to a higher hetero-deformation induced (HDI) stress in the multiple-gradient samples. A combination of a strong and persistent transformation-induced plasticity effect, active HDI strengthening and HDI hardening, and dislocation strengthening contributed to the superior strength–ductility synergy of the gradient-structured medium-Mn steel.

Enhanced dynamic deformability and strengthening effect via twinning and microbanding in high density NiCoFeCrMoW high-entropy alloys

High density alloys with enhanced deformability and strength are urgently required in energy, military and nuclear industries, etc. In this work, we present a new kind of NiCoFeCrMoW high entropy alloys (HEAs) which possess higher densities and sound velocities than copper. We systematically investigate the phase structure, quasi-static tensile, dynamic compression and related deformation mechanism of these HEAs. It is shown that single FCC or FCC + μ dual phases were formed in the HEAs depending on Mo and W content and annealing temperature. Excellent quasi-static tensile and dynamic compression properties have been achieved for these HEAs, e. g. Ni30Co30Fe21Cr10W9 HEA annealed at 1573 K exhibited a yield and ultimate tensile strength and elongation of ∼364 MPa, ∼866 MPa and ∼32%, respectively, in quasi-static test; a yield strength of ∼710 MPa and no fracture under the dynamic strain rate of 4100 s−1. Superior strain rate sensitivity (SRS) of yield strength than that of previously reported FCC HEAs have been evidenced. The dynamic stress-strain constitutive relation can be described by the modified Johnson-Cook model. As for the dynamic deformation mechanism, it is envisaged that the regulation of stacking fault energy and Peierls barrier in current HEAs resulted in occurrences of abundant nanoscale deformation twins and microbands during high strain rate compression. The synergistic microbanding and twinning effectively contributes to the enhanced dynamic deformability and strengthening effect. Besides, the interactions of dislocations with precipitates, stacking faults (SFs) with twins, and between SFs also contribute to extraordinary work-hardening capacity.

Research on the hot tensile deformation mechanism of Ti-6Al-4 V alloy sheet based on the α + β dual phase crystal plasticity modeling

In order to predict the microstructure evolution of α + β dual phase Ti-6Al-4 V alloy during high temperature tensile deformation and reveal its deformation mechanism, a dual phase crystal plasticity simulation model based on dislocation density was established. The uniaxial hot tensile test of Ti-6Al-4 V alloy sheets was carried out at different temperatures with the same strain rate, and the stress-strain curves were obtained. The initial microstructure of the undeformed Ti-6Al-4 V alloy sheet was obtained by electron backscatter diffraction (EBSD). Based on the obtained microstructure information, a representative volume element (RVE) containing α + β phase was constructed. The validity of the model was verified by comparing the stress-strain curves obtained from experiments and full field crystal plasticity simulations. According to the crystal plasticity simulation model, the deformation inhomogeneity and dislocation density evolution of Ti-6Al-4 V alloy at high temperature were studied. For α phase, the growth rate of dislocation density in basal slip system and prismatic slip system decreases with the increase of temperature. For β phase, the dislocation density growth rate of all slip systems increases with the increase of temperature. Dislocation density concentration occurs at the phase boundary of the two phases and decreases with the increase in temperature.

Achieving High Tensile Strength of Heat-Resistant Ni-Fe-Based Alloy by Controlling Microstructure Stability for Power Plant Application

A new, wrought Ni-Fe-based alloy with excellent creep rupture life has been developed for 700 °C-class advanced ultra-supercritical (A-USC) steam turbine rotor application. In this study, its tensile deformation behaviors and related microstructure evolution were investigated. Tensile tests were carried out at room temperature, 700 °C, and 750 °C. The results show that the Ni-Fe-based alloy has excellent yield strength at 700 °C, which is higher than that of some other Ni-based/Ni-Fe-based alloys. The fracture surface characteristics indicate trans-granular and intergranular fracture modes at room temperature, 700 °C, and 750 °C. However, the intergranular fraction mode became dominant above 700 °C. Dynamic recrystallization occurred at 700 °C and 750 °C with increasing average misorientation angles. The volume fraction of the γ′ precipitate was around 20%, and the average size of the γ′ precipitates was around 30 μm, which had no noticeable change after the tensile tests. The predominant deformation mechanisms were planar slip at room temperature, bypassing of the γ′ precipitates by the Orowan mechanism, and dislocation shearing at 700 °C and 750 °C. The tensile properties, fracture characteristics, and deformation mechanisms have been well-correlated. The results are helpful in providing experimental evidence for the development and optimization of high-temperature alloys for 700 °C-class A-USC applications.

Effect of early stage of κ-carbides precipitation on tensile properties and deformation mechanism in high Mn–Al–C austenitic low-density steel

High Mn–Al–C austenitic low-density steels possess the great combination of strength and ductility due to their excellent strain hardening capability. At present, there is no consensus on the controlling factors of the deformation mechanism, of which κ-carbides may play an important role. Abundant literatures have investigated the influence of long-term or peak aging heat-treatment so far, while few reports have focused on the early stage of κ-carbides precipitation. In this study, samples characterized by short-range order (SRO) and early precipitation states of κ-carbides were processed by rapidly quenched (RQ) and water quenched (WQ) treatment, respectively. When the ordering process from SRO to ultrafine nano κ-carbides was stopped by the increase of cooling rate, the ultimate tensile strength of the alloy was significantly increased without a decrease in yield strength, which indicates a dramatic increase in the work hardening rate. TEM investigation clearly revealed that the precipitation of κ-carbides slowed down the evolution of microstructure, which is an essential factor for the deterioration of work hardening capability. Another interesting result was that although the stacking fault energy (SFE) of the alloy was high (∼108 mJ/m2), twinning phenomena was observed in the RQ sample, implying that SRO should assist the formation of deformation twins, which provided a novel example for the development of twins in high SFE alloys.

Molecular Dynamics Simulations of Polymer Grouting Material: Its Mechanical Behavior under Uniaxial Tension, Cyclic Tensile Loading, and Stress Relaxation

At present, polyurethane (PU) has been extensively used as a grouting material in civil engineering. The mechanical properties of PU are the key to achieving the desirable grouting effect. This study presents the research results of the mechanical behavior of PU matrix under tensile, successive cyclic tensile, and stress relaxation at the nanoscale, using the coarse-grained molecular dynamics simulation method. The influences of the number of molecule chains and strain rate on the tensile mechanical properties are discussed, and the tensile deformation mechanism of PU matrix is revealed. The tensile strength of PU matrix is independent of loading path, and after yielding, the strain of PU matrix contains the elastic strain, plastic strain, and viscous strain. In the stress relaxation process, the evolution of the axial stress is mainly caused by the varied van der Waals interactions. The stress relaxation behavior of PU matrix can be described by the viscoelastic model consisting of one elastic element in parallel with one Maxwell element.

Molecular dynamics simulation of the tensile response and deformation mechanism of diamond/TiC combinations

The diamond materials combine several prominent intrinsic performances, such as high transmittance, low microwave dielectric loss, and so on. A nanoscale carbide layer will be indispensably produced on their surface to guarantee the diamond can be wetted by metallic parts, for example the diamond microwave window for use in thermonuclear fusion reactor. The mechanical performance of the diamond/carbide layer interfacial bonding, which remains unknown because of dimensional limitation, will be critically vital. In this work, molecular dynamics (MD) simulation was conducted to explore the fracture mechanism of diamond/TiC combinations under uniaxial tension. The deformation behavior of (001), (110), and (111) single-crystalline (SC) TiC on diamond was investigated based on the stress–strain curve, fracture process, and dislocation evolution. The crystallographic orientation-dependent fracture modes were revealed. For the case of TiC(001) and TiC(110), the plastic fracture happened. The TiC{111} dislocations would be first emitted from the interface. Different dislocation morphologies were presented, such as stair-rod dislocations and dislocation tangles for TiC(001), as well as geometrically necessary dislocations for TiC(110). For the TiC(111), the brittle fracture took place because most easily activated slip planes were perpendicular to the force direction. Our findings revealed the nanomechanical behaviors and corresponding deformation mechanisms of the diamond/TiC combinations, facilitating the design and development of nanostructured combinations with superior mechanical performance.

Temperature dependence of tensile deformation mechanisms in a powder metallurgy Ni–Co–Cr based superalloy with Ta addition

To further develop Ni-based powder metallurgy (PM) superalloys for aero-engines, it is critical to understand their deformation mechanisms at various service temperatures. For turbine disks, the tensile strength and absorbed impact energy are critical parameters. The varying stress during tensile deformation makes it essentially different from creep. In this study, a high-performance PM superalloy with various Ta contents was evaluated by tensile tests at different temperatures from room temperature to 815 °C. The relationship between the temperature and plastic deformation mechanisms was explored at multiple scales using scanning electron microscopy and transmission electron microscopy, and the temperature dependence of the deformation mechanism map was established. The results demonstrated that the main deformation mechanism gradually changed from antiphase boundary shearing to superlattice stacking fault shearing as the temperature increases. The extended stacking faults (ESFs) were the source of the microtwins, which extended within the individual grains and thickened with increasing temperature. In addition, a novel mechanism of ESF formation was observed, i.e., Shockley shearing separated by one layer of atoms. Furthermore, the effects of Ta on the tensile strength and plasticity in PM superalloys were discussed.

Tensile properties and deformation mechanisms of a new Ni–Co base superalloy from room temperature up to 750 °C

In this article, we developed a new Ni–Co base superalloy with excellent mechanical properties in the temperature region from room temperature to 750 °C. The yield and tensile strengths of the alloy at room temperature are ∼1212 MPa and ∼1638 MPa, respectively, and they can still reach ∼1077 MPa and ∼1233 MPa at 750 °C, maintaining a good intermediate temperature strength. Microstructure characterizations show that the plastic deformation is mainly dominated by anti-phase boundary (APB)-coupled dislocation pair shearing γ′ precipitates at room temperature. With increasing the temperature, although the dislocation pair shearing still dominates, stacking fault (SF) shearing and nanotwinning also appears and contributes minor to the plastic deformation. The interactions among dislocations, SFs and nanotwins finally results in the decent working hardening ability even at such a high temperature up to 750 °C, which in turn gives rise to the ultrahigh ultimate tensile strength of the Ni–Co base superalloy.

Temperature dependence of tensile behavior, deformation mechanisms and fracture in nitrogen-alloyed FeMnCrNiCo(N) Cantor alloys

Among a family of the multi-principle-element alloys, a high-entropy Cantor alloy attracts much attention due to the striking temperature dependence of strength properties, strong grain boundary hardening and the excellent low-temperature ductility. Cantor alloy is a substitutional concentrated solid solution, thus, its strength properties and strain hardening could be additionally enhanced by interstitial hardening. Here we explore the effect of nitrogen alloying with atomic concentrations of 0.8%, 1.4% and 1.6% on a temperature dependence (temperature range from 77 to 473 K) of the microstructure, mechanical properties, and fracture micromechanisms of FeMnCrNiCo alloy with the focus on low-temperature deformation regime. Nitrogen-alloying promotes the expansion of a crystal lattice with a linear increase of a lattice parameter of the alloy with nitrogen content, ∆a/∆CN = 0.625 pm/at%. Nitrogen-bearing FeMnCrNiCo(N) alloys possess stronger temperature dependence of a yield strength relative to the Cantor alloy, and nitrogen forces both athermal and thermal components of the stress. The solid-solution strengthening of Cantor alloy is proportional to the nitrogen concentration Δτ ~ CN, and the value (ΔYS/ΔCN) for the coarse-grained FeMnCrNiCo(N) alloys is a temperature-dependent parameter (ΔYS/ΔCN = 97 MPa/at% at RT and ΔYS/ΔCN = 146 MPa/at% at 77 K). Dislocation slip is a dominating deformation mechanism of the nitrogen-alloyed alloys along the whole range of the deformation temperatures. A decrease in test temperature and nitrogen-alloying both force the tendency to the planar slip and facilitate strain hardening. Despite a weak effect of nitrogen on a stacking fault energy of the Cantor alloy and high deforming stresses in FeMnCrNiCo(N) alloys, nitrogen-containing alloys show low activity of the mechanical twinning. Opposite effects of the nitrogen-alloying on the elongation of the Cantor alloy were found for different deformation regimes: positive at T > 250 K (elongation increases with nitrogen-alloying) and negative at T < 250 K (it decreases in nitrogen-bearing alloys). For FeMnCrNiCo(N) alloys, the appearance of the ductile-to-brittle transition in low-temperature deformation regime is associated with the brittle intergranular fracture of the specimens alloyed with nitrogen CN ≥ 1.4 at%.

Effect of temperature on tensile behavior, fracture morphology and deformation mechanisms of Nickel-based single crystal CMSX-4

The effect of temperature on the tensile behavior and deformation mechanisms in a single crystal superalloys CMSX-4 is addressed and deduced by transmission electron microscopy in the temperature range from room temperature to 1100 °C. It is found that the tensile yield strength reaches a peak at 800 °C. And then, the yield strength decreases with increasing temperature. At room temperature, anti-phase boundary shearing dominates the plastic deformation. From 800 °C to 850 °C, the plastic deformation mechanism is mainly controlled by stacking fault shearing. The Kear-Wilsdorf locks have also appeared. When the temperature reaches at 950 °C, dislocation loops with anti-phase boundary shearing of the γ ′ precipitates are presented. Above 950 °C, the plastic deformation mechanism is processed by the rafted structure of the γ ′ precipitates by-passing, i.e., Orowan by-passing and dislocation climb. Finally, according to the experimental results, the variety of stacking faults with temperatures and the relationship between the yield strength and plastic deformation mechanism are discussed. • The tensile deformation mechanism of CMSX-4 is dependent on the temperatures. • The Kear-Wilsdorf locks are responsible for higher tensile yield strength at 800 and 850 °C. • The temperature for SSFs formation under tensile tests is lower than that at compression tests. • The deformation mechanism at 950 °C is controlled by dislocation loops with APB cutting of γ ′ precipitates. • Above 950 °C, the deformation mechanism is addressed by rafted γ ′ phase by-passing.

Effect of copper addition on tensile behavior in Fe-Cr-Ni stable austenitic stainless steel

Effects of Cu on tensile properties and deformation mechanisms were investigated in the stable Fe-Cr-Ni austenitic stainless steel with different wt% of Cu. Addition of Cu slightly decreased the yield strength and negligibly affected the ultimate tensile strength, while it induced a considerably large reduction of fracture elongation. Deformation twins were generated during the tensile deformation, and fraction of deformation twins decreased with increasing Cu content. However, degree of twinning was similar, regardless of Cu content, at the same tensile strain, which indicated that development of twins was interfered by earlier fracture triggered by Cu addition and hardly contributed to different hardening behavior at the early stage of deformation. Cu significantly altered the motion of dislocations. The low-Cu-containing alloy mainly developed tangled dislocations and cellular structures, whereas the high-Cu-containing alloy did planar slip and high density of dislocation walls. Although the addition of Cu decreased the shear modulus and increased the stacking fault energy, dislocation substructure changed from tangled to planar slip with increasing Cu content. This indicated that slip planarity of high-Cu-containing alloys might be originated from the formation of short-range ordering or clustering, thereby leading to the local stress concentration and reduction of the elongation.

Stabilized sub-grain and nano carbides-driven 1.2 GPa grade ultra-strong CrMnFeCoNi high-entropy alloy additively manufactured by laser powder bed fusion

• Carbon-containing CrMnFeCoNi high-entropy alloys with varying carbon content were manufactured by laser powder bed fusion (L-PBF). • Aging treatment effects on the microstructural evolution and mechanical properties were investigated. • The alloy aged at 650 °C showed ultimate tensile strength of 1.2 GPa at room temperature. • The main deformation mechanism changed from deformation twinning to dislocation-mediated slip. High-entropy alloys (HEAs) with interstitial atoms that are produced by additive manufacturing have gained intensive interest in the materials science community because of their suitability for constructing high-strength net-shape components. Here, a strategy to additionally enhance the strength of selective laser melted carbon-containing HEAs was investigated. The as-built carbon-containing HEAs (C x (Cr 20 Mn 20 Fe 20 Co 20 Ni 20 ) 100- x ( x = 0.5 at.%, 1.0 at.%, and 1.5 at.%)) contain supersaturated carbon, and the extent of supersaturation increases as the carbon content increases. When subjected to aging treatment at 650 °C for 1 h, the microstructure of the three alloys did not change at the grain scale. However, the microstructure at the sub-grain scale changed markedly, and these changes influenced the tensile properties and deformation mechanism. In particular, the tensile strength of aged 1.5C-HEA at 650 °C was ∼1.2 GPa at room temperature, which is higher than those reported for CrMnFeCoNi HEAs. Furthermore, the main deformation mechanism changed from deformation twinning to dislocation-mediated slip, resulting in much higher strain hardening capacity after the aging treatment. This work led to the development of an alternative promising method that involves tailoring the microstructure, to enhance the mechanical properties of additively manufactured metallic materials that contain interstitial atoms.

Formation of hypoeutectic structure and strengthening mechanism of Co4Cr1.5Fe1.5Ni5 high entropy alloy alloyed by Al

To reveal the phase formation mechanism and the strengthening mechanism, the AlxCo4Cr1.5Fe1.5Ni5 alloys (x = 1.0, 1.2, 1.4, 1.6, 1.8, 2.0) were prepared by arc melting. Phase formation and prediction, tensile properties, strengthening mechanism and deformation mechanism were researched in detail. Results show that the microstructure of AlxCo4Cr1.5Fe1.5Ni5 alloys changes from single FCC phases (x ≤ 1.4)) to FCC and BCC phases (x＞1.4), which was in good agreement with the calculated phase diagram (CALPHAD) prediction. The lower mixing enthalpy of Ni-Al leads to the segregation of Al element at the inter-dendritic region, which promotes the formation of BCC and FCC lamellar structure in hypoeutectic Al2Co4Cr1.5Fe1.5Ni5 alloy. The ultimate tensile strength of Al2Co4Cr1.5Fe1.5Ni5 alloy is 835 MPa, meanwhile the fracture strain is 31.8 %. The tensile strength of Al2Co4Cr1.5Fe1.5Ni5 alloy is attributed to the interface strengthening and the solid solution strengthening. The massive cross slip of dislocations in primary FCC phases and the dense dislocations blocked by the FCC-BCC interface increase the tensile strength. The interface barrier strength of the BCC-FCC interface in Al2Co4Cr1.5Fe1.5Ni5 alloy was estimated to be 3.9 GPa, which shows the higher barrier strength than conventional BCC-FCC interfaces. Coupled effects of the primary FCC and the lamellar structure of FCC and BCC phases will maintain good mechanical properties.

Tensile creep behavior of HfNbTaTiZr refractory high entropy alloy at elevated temperatures

Tensile creep, which is one of the most important deformation modes for high temperature applications, is rarely reported for refractory high entropy alloys (RHEAs). In the present study, the optical floating zone (OFZ) technique was used to fabricate HfNbTaTiZr with grain size larger than 1 mm on average; tensile creep tests under vacuum at 1100-1250°C and stepwise loading of 5–30 MPa were conducted. The stress exponents and creep activation energies were determined to be 2.5–2.8 and 273 ± 15 kJ mol–1, respectively. The stress exponents determined have suggested solute drag creep behavior, and deformation was governed by a/2<111> type dislocations. To elucidate the effect of alloying constituents on solute drag creep, intrinsic diffusion coefficients of all elements were determined by simulation, and theoretical minimum creep strain rates were compared with those of experimental values. Analysis suggests that creep rate of HfNbTaTiZr appears to be controlled by Ta, which possesses the lowest intrinsic diffusivity and contributes the most to drag dislocations. To our knowledge, this work is the first to report tensile creep deformation mechanism of HfNbTaTiZr, especially up to 1250°C.

Initial Microstructure Effects on Hot Tensile Deformation and Fracture Mechanisms of Ti-5Al-5Mo-5V-1Cr-1Fe Alloy Using In Situ Observation

The hot tensile deformation and fracture mechanisms of a Ti-5Al-5Mo-5V-1Cr-1Fe alloy with bimodal and lamellar microstructures were investigated by in situ tensile tests under scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The results show that the main slip deformation modes are prismatic slip ({11¯00}&lt;112¯0&gt;) and pyramidal slip ({11¯01}&lt;112¯0&gt;) under tension at 350 °C. In the bimodal microstructure, several parallel slip bands (SBs) first form within the primary α (αP) phase. As the strain increases, the number of SBs in the αP phase increases significantly and multislip systems are activated to help further coordinate the increasing deformation. Consequently, the microcracks nucleate and generally propagate along the SBs in the αP phase. The direction of propagation of the cracks deflects significantly when it crosses the αP/β interface, resulting in a tortuous crack path. In the lamellar microstructure, many dislocations pile up at the coarse-lath α (αL) phase near the grain boundaries (GBs) due to the strong fencing effect thereof. As a result, SBs develop first; then, microcracks nucleate at the αL phase boundary. During propagation, the cracks tend to propagate along the GB and thus lead to the intergranular fracture of the lamellar microstructure.

Effects of preexisting cracks on tensile behavior and deformation mechanism of boron nitride nanoribbons: A molecular dynamics investigation

Effects of preexisting cracks on tensile behavior and deformation mechanism of boron nitride nanoribbons: A molecular dynamics investigation

Tensile deformation behaviors of laser powder bed fusion fabricated Al–Mn-Sc alloy with heterogeneous grain structure

The processability of laser powder bed fusion (LPBF) fabricated Al alloys can be significantly improved by the introduction of grain refinement inoculates. However, tensile testing results showed that the fabricated alloys exhibited unusual deformation characteristics, including discontinuous yielding, Lüders elongation and low work hardening behaviors. In this study, the underlying tensile deformation mechanisms of the inoculates modified Al alloys after LPBF processing were elucidated through various characterization techniques, using the recently developed Al–Mn-Sc alloy as an example. It was found that the “extra hardening” effect caused by the fine grain structures promoted the discontinuous yielding behavior, while lack of mobile dislocations within the fine grain regions triggered the Lüders bands propagation. On the other hand, the high initial strain hardening rate contributed to the strong work hardening behaviors of the fabricated alloy with lower fine grain fractions, whereas all alloys with different heterogeneous grain structures proved similar dynamic recovery behaviors at higher strains.

Tensile deformation behaviors of Ti-6.5Al-3.5Mo-1.5Zr-0.25Si alloy with different percentages of primary α phase

The mechanical properties and tensile deformation mechanism of Ti-6.5Al-3.5Mo-1.5Zr-0.25Si alloy (TC11) with different percentages of primary α phase (αp) were studied by conventional and interrupted tensile tests, respectively. The results show that the strength of TC11 alloy increases with the increase of the percentage of αp. During tensile deformation, TC11 alloy with different percentages of αp exhibits similar behavior. The deformation mechanism in αp transforms from single slip to multiple slip. While, the microcracks first initiate at the interface of two phases, propagate along it, and then propagate through the transformed β phase (βt) and finally through αp. Finally, a method for predicting the strength of TC11 alloy considering the sizes of αp and βt is proposed.

Effects of hot isostatic pressing treatment on the microstructure and tensile properties of Ni-based superalloy CM247LC manufactured by selective laser melting

This study manufactured CM247LC Ni-based superalloy, which has outstanding mechanical properties, using the laser powder bed fusion (L-PBF) method and selective laser melting (SLM). Furthermore, the effect of hot isostatic pressing (HIP) post treatment on the microstructure and mechanical properties of SLM-built CM247LC was investigated. The defect characteristics of SLM-built superalloy changed significantly according to scan speed and hatch space, and it achieved the optimal microstructure at an intermediate scan speed (600 mm/s). SEM, EBSD, and ECCI analyses of the as-built alloy identified grains that developed in the build direction, sub-grains consisting of dislocation networks and MC carbides. In addition, γ’ phase formed evenly throughout the sample after HIP post treatment. The as-built CM247LC showed a yield strength of 933.5 MPa and tensile strength of 1144.0 MPa. In the case of the HIP alloy, the yield strength remained at a similar level, but tensile strength increased significantly up to 1457.1 MPa, and tensile elongation increased four times compared to the as-built alloy. Based on the above findings, this study discussed the correlations between microstructure, improved tensile properties and deformation mechanism.