Bimodal Grain Research Articles

Unveiling synergistic strength and plasticity enhancement of Mg–Zn–Mn alloy via closed forging extrusion

A cost-effective, high-performance Mg-2.0Zn-1.5Mn alloy was fabricated using closed forging extrusion (CFE). The results reveal that CFE can promote a dynamic recrystallization (DRX) ratio and enhance the residual dislocation density in deformed grains and subgrains. Grain refinement is achieved through multiple DRX mechanisms, particle-stimulated nucleation, and pinning effects. In addition, the basal texture and precipitation behavior are significantly influenced by pre-forging in CFE. Finally, grain refinement and substantial residual dislocations result in a good combination of strength and plasticity, with the ultimate tensile strength of 400 MPa and elongation of 22.1%, respectively. A novel strategy for regulating the bimodal grain structure is proposed to guide the optimization of the mechanical performance of rare-earth free Mg alloys.

Influence of SiC particles on the microstructure and mechanical behaviors of AlMgScZr alloy processed by laser powder bed fusion

Laser powder bed fusion (LPBF) of AlMgScZr alloy has garnered significant attention as a high-strength aluminum alloy. However, its low modulus, Portevin-Le Chatelier (PLC) behavior, and weak strain hardening capability restrict its application in the aerospace sector. In this study, SiC/AlMgScZr composites with different SiC content have been successfully fabricated using LPBF. The inherent bimodal grain structure of AlMgScZr alloy was not completely altered by the addition of SiC particles. However, with increasing SiC content, heat accumulation increased, and the solidification cooling rate decreased. This led to an increase in the size of α-Al grains in the 5 wt% SiC/AlMgScZr composites. Meanwhile, movable dislocations can be efficiently preserved inside the grains, where they effectively accumulate and become entangled. Consequently, the strain hardening capability of the 5 wt% SiC/AlMgScZr composites improved by approximately 58 % compared to AlMgScZr alloy, with a strain hardening index (n) reaching 0.29. Additionally, the addition of SiC particles led to an increase in the elastic modulus (81.0 GPa). Furthermore, the reaction between Mg atoms and SiC particles resulted in the formation of Mg2Si, which altered the distribution of Mg elements and initiated the reactive precipitation of a Mg-rich phase. There is no competition between the diffusive migration of solute atoms and the motion of movable dislocations within the composites. The additional SiC particles effectively eliminated the PLC effect in the LPBF of AlMgScZr alloy. This work provides essential guidance for developing high-strength and high-stiffness aluminum matrix composites with excellent processing properties in LPBF technology.

Synergy of strength-ductility in a novel Al-Zn-Mg-Cu-Zr-Sc-Hf alloy through optimizing hierarchical microstructures

The strength improvement in the heat-treatable Al-Zn-Mg-Cu alloys is generally achieved by increasing the volume fraction of nanoprecipitates and reducing the grain size. However, utilizing one of them usually leads to a drastic decrease in ductility. Herein, we architect a hierarchical microstructure integrating bimodal grain structures, nanoprecipitates, and hard-brittle coarse particles wrapped by ductility coarse grain (CG) bands via conventional cold rolling (CR) deformation and heat treatment methods to break the strength-ductility dilemma in the Al-8.89Zn-1.98Mg-2.06Cu-0.12Zr-0.05Sc-0.05Hf (wt.%) alloy. The results reveal that the coupling of high-volume fraction (∼1.2%) nanoprecipitates, ∼52% narrow CG bands, and most coarse particles encapsulated by CG bands contribute to the 45% CR sample with outstanding overall mechanical properties (a tensile strength of 655 MPa, a yield strength of 620 MPa, and an elongation of 15.5%). Microstructure-based strength analysis confirms that the high strength relates to a trade-off between the hierarchical features, namely high-volume fraction nanoprecipitates to counterbalance the strength loss caused by grain coarsening. The excellent ductility is due to the introduction of medium CG content with a narrow width that can trigger a cross-scale strain distribution during plastic deformation, suppressing the catastrophic failure in the fine grain (FG) regions and facilitating the dimple fracture along the CG bands. This study proposes a feasible approach for tailoring hierarchical microstructures in Al-Zn-Mg-Cu alloys to achieve a superior strength-ductility combination.

Effect of Er addition on the microstructure, mechanical properties and corrosion behaviour of Al-Zn-Mg-Cu alloy manufactured by laser powder bed fusion

The purpose of this study is to gain a deeper understanding of the effects of rare-earth element Er on the microstructure and properties of Al-Zn-Mg-Cu alloy manufactured by laser powder bed fusion (LPBF). Compared with the as-printed Al-Zn-Mg-Cu alloy without Er addition, the as-printed Al-Zn-Mg-Cu-Er alloy with a bimodal grain structure had finer cellular structures and denser precipitation phases, which significantly improved the alloy's mechanical and corrosion resistance properties. The tensile strength of the as-printed Al-Zn-Mg-Cu-Er alloy was 383 MPa, which is 137 MPa higher than that of the as-printed Al-Zn-Mg-Cu alloy without Er addition. It was intended to use T6 heat treatment process to further regulate the mechanical properties of the as-printed alloy, but the formation of Si-rich hard and brittle eutectic phases with sizes of 2–5 μm in the matrix resulted in a decrease in the strength of the alloy, which is contrary to the traditional 7xxx aluminum alloys. Besides, the addition of Er element improved the alloy's corrosion resistance by decreasing the corrosion current density and raising the intergranular corrosion (IGC) resistance, and the maximum intergranular corrosion depth decreased from 174 µm to 68 µm after Er addition.

Bimodal-grain structure enables superior strength-ductility synergy of pure Al

Developing materials with a strength-ductility synergy was eternally desirable in structural materials. Here, we prepared the bimodal grain structures through the designed powder assembly approach without introducing other elements, which utilized stable dislocations and substructures to regulate fine-grained structures. During the strain, geometrically necessary dislocations formed at fine/coarse grain boundaries to coordinate deformation induced by plastic incompatibility. The stress field induced by these previously accumulated geometrically necessary dislocations interacted with the subsequently formed dislocations. The dislocation movement was thus dynamically coordinated, which in return enlarged the work-hardening region of the materials. Compared with the cast-rolled pure Al, the ultimate tensile strength of the prepared pure aluminum was 212±2 MPa, which was increased by about 102 % and maintained the desirable elongation of 13.5±0.7 %.

Heterogeneous microstructure and mechanical properties of carbon-doped FeCoCrNiMn high-entropy alloy

Heterogeneous microstructure with nano-precipitate and bimodal grain size distribution was obtained in a FeCoCrNiMn high-entropy alloy (HEA) doped with 0.5 at.% C by a controlled thermo-mechanical treatment. The coarse M23C6 carbides tend to aggregate along the fine grain boundaries. Compared to the sample with homogenous microstructure, the heterostructure FeCoCrNiMn−0.5at.%C HEA has approximately the same average grain size of 4.8 μm. However, it shows bimodal grain size distribution and higher volume fraction of the fine grains (<3 μm), resulting in the increase of yield strength from 552 to 632 MPa. The sample with heterostructure presents different mechanical responses and deformed microstructures in different regions, accounting for significant strain localization and high density of the geometrically necessary dislocations during tensile deformation. These deformation characteristics are beneficial to the enhancement of strain hardening capacity, thereby promoting strength−ductility synergy.

Slip-band-driven dynamic recrystallization mediated strain hardening in HfNbTaTiZr refractory high entropy alloy

Refractory high-entropy alloys (RHEAs) exhibit outstanding strength at room temperature, but their high-temperature applications are hindered by severe strain-softening. Here, we report slip-band-driven dynamic recrystallization to enhance the high-temperature strain hardening of HfNbTaTiZr RHEA. By introducing partial lattice defects through hot forging, we increase the nucleation sites for dynamic recrystallization during subsequent thermomechanical deformation, thus suppressing the strain-softening behavior. We reveal that the high-temperature deformation is governed by the formation of heterogeneous bimodal grains along slip bands, which effectively constrain dislocation motion and improve strength, while microbands prevent premature failure. The fracture mode also changes from ductile to mixed to cleavage-dominated with increasing temperature. Our results demonstrate a simple and effective method for overcoming high-temperature strain-softening for BCC high entropy alloys.

Bimodal grain structure and balanced mechanical properties of cryo-rolled Mg-Zn-Y alloy via twinning-induced recrystallization

The microstructure and mechanical properties of the hot-rolled and cryo-rolled Mg-2Zn-0.85Y (wt.%) alloys before and after annealing were studied comparatively. The results show that the cryo-rolled alloy after annealing exhibits a strength and plasticity product of up to 6885 MPa·%, which is the highest among these alloys. The good combination of strength and ductility is mainly attributed to the bimodal grain structure with a weakened texture. Recrystallization primarily occurs in grains with <112¯0>/30.1° twinning, but not in the grains without <112¯0>/30.1° twinning, resulting in the formation of the bimodal structure. The cryo-rolling process could become a promising method for regulating the microstructure and properties of magnesium alloys.

Biodegradable PMMA coated Zn–Mg alloy with bimodal grain structure for orthopedic applications - A promising alternative

The study examines the impact of microstructure and polymethyl methacrylate (PMMA) grafting on the degradability of Zn–Mg alloys. The mechanical properties of a Zn alloy containing 0.68 wt% Mg and extruded at 200 °C are enhanced for degradable load-bearing applications, addressing a crucial need in the field. The material exhibits a bimodal grain size distribution that is random texture, consisting of secondary phases, grains, and sub-grains. With an elongation to failure of 16 %, the yield and ultimate tensile strengths are 325.9 and 414.5 MPa, respectively, and the compressive yield strength is 450.5 MPa.The “grafting-from” method was used to coat a few micrometers thick of PMMA on both bulk and scaffold Zn alloys to mitigate the corrosion rate. The last one is a porous structure, with a porosity of 65.8 %, considered as in the first approach of an orthopedic implant. After being immersed for 720 h, the PMMA-grafted bulk alloy's corrosion rate decreased from 0.43 to 0.25 mm/y. Similarly, the scaffold alloy's corrosion rate reduced from 1.24 to 0.49 mm/y. These results indicate that the method employed could be used for future orthopedic applications.

Strengthening mechanisms analysis and tailoring of bimodal grain structures for enhanced strength in CoCrFeMnNi high-entropy alloys

Strengthening mechanisms analysis and tailoring of bimodal grain structures for enhanced strength in CoCrFeMnNi high-entropy alloys

Effect of Annealing Temperature on Microstructure and Properties of Solid Solution Extruded Mg–2.0Zn–1.0Y–0.5Zr Alloys

In this investigation, the effects of different annealing temperatures (180, 200, 220, 240, 260, and 280 °C) on the microstructure evolution and properties of an extruded Mg–2.0Zn–1.0Y–0.5Zr (wt%) magnesium alloys were determined. Optical microscopy (OM), scanning electron microscopy (SEM), immersion corrosion, electrochemical corrosion experiments, and tensile testing were performed. Research has found that combining hot extrusion with subsequent low-temperature annealing significantly improves the strength, plasticity, and corrosion resistance of alloys due to grain refinement and a reduced dislocation density. The alloy was completely recrystallized at an annealing temperature of 240 °C for 4 h after solid solution extrusion, and the grains were fine and uniform, demonstrating the best comprehensive properties. Its corrosion rate, ultimate tensile strength, yield strength, and elongation were 0.454 ± 0.023 mm/y, 346.7 ± 8.9 MPa, 292.4 ± 6.9 MPa, and 19.0 ± 0.4%, respectively. The corrosion mechanism of the specimens under extruded and annealed conditions was analyzed. After annealing at 240 °C for 4 h, the dislocation and bimodal grain structure of the samples were almost eliminated, resulting in uniform and fine grains, which were conducive to the formation of a more uniform and denser oxide film, thus improving the corrosion resistance of the alloy.

Mechanical and magnetic properties of phase separated Cu50Fe50 (at%) alloys synthesized by mechanical alloying and spark plasma sintering

A bulk Cu50Fe50 (at%) alloy was prepared by mechanical alloying (MA) of elemental Cu and Fe powders for 20 h, followed by the spark plasma sintering (SPS). All the powder and bulk samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical and magnetic properties of the bulk samples were also evaluated. From 1 h to about 10 h of milling, the formation of nanocrystalline Cu-rich face-centered cubic solid solution (FCC γ phase) and Fe-rich body-centered cubic solid solution (BCC α phase) was observed. Above 10 h of milling, the γ and α phases merged to form a single-phase face-centered cubic (γS) solid solution till 20 h. Subsequently, the 20 h MA powder was consolidated using spark plasma sintering (SPS) at three different temperatures: 519 ℃ (0.5 Tm), 677 ℃(0.6 Tm), and 835 ℃ (0.7 Tm), where Tm is the average melting point of the alloy (1310 ℃). In all three samples, the metastable γS phase decomposed into the nanocrystalline Cu-rich γ and Fe-rich α phases during SPS. Notably, the 0.7 Tm sample exhibited a better balance between strength and ductility by demonstrating a compressive yield strength of 886 MPa and an ultimate compressive strength of 1166 MPa with a ductility of 15%. The high strength and ductility are attributed to a bimodal grain size distribution, i.e., a few microns thick and continuous Cu-rich γ grain boundary phase and an intragranular nanocrystalline mixture of γ and α phases. In addition to its excellent mechanical properties, the 0.7 Tm sample displayed favorable soft ferromagnetic characteristics exhibiting a saturation magnetization (Ms) of 66 emu/g and a coercivity (Hc) of 16 Oe.

Achieving strength-ductility synergy in Al-4.5 wt%Cu binary alloy through semisolid isothermal treatment coupled with ECAP

Bulk nanostructured (NS) aluminum alloys typically have high strength but with extremely limited ductility. An advanced two-step thermomechanical processing, i.e. semisolid isothermal treatment coupled with equal-channel angular pressing (ECAP), was adopted to achieve high strength (413±2.5 MPa) and high elongation (12.0±0.6 %) in bulk NS Al-4.5 wt%Cu binary alloy. The broken nanoscale Al2Cu particles (∼50–80 nm) from lamellar eutectic, dynamic precipitations Al2Cu (∼30–60 nm), refined grains, and high-density dislocations are believed to be key contributors for the high strength. The bimodal grain structure, which caused a well-balanced work hardening and a good deformation compatibility, is critical for the enhanced strength-ductility synergy. This work demonstrates a new approach for improving strength-ductility synergy in interdendritic-eutectic type aluminum alloys.

Using multiscale second phases to fabricate high-performance Mg-3Al-3Nd-0.1Mn alloys with bimodal grain structures

The quest for magnesium alloys that combine high strength and high ductility drives significant research effort aimed at broadening their use in various sectors. In this research, a low-alloy Mg-3Al-3Nd-0.1Mn (AEM330) was successfully prepared through Hard Plate Rolling (HPR), achieving an ideal combination of high strength and ductility via carefully modifying grain structure at lower rolling temperature. The optimized processing conditions led to an alloy with an ultimate tensile strength of 427 MPa and an notable elongation of 11.4 %. The AEM330 processed by HPR displayed unique bimodal grain structure with coarse grains (CGs) sizes ∼13.66 µm and fine grains (FGs) sizes ∼2.36 µm, and their strength and ductility were found to be directly related to the microstructural differences between CGs and FGs. A crucial discovery of this study is the essential role of the Al2Nd phase (larger than 1 µm) and the Al11Nd3 phase (smaller than 1 µm) in forming bimodal grain structure. The former phase plays a significant role in recrystallization by particle-stimulated nucleation (PSN), and the latter restricts grain size via Zener pinning. Furthermore, it was found that the ratio of CGs to FGs could be controlled by modifying the rolling temperature. Importantly, the simple composition and direct shaping process of the AEM330 alloy not only improve its cost-effectiveness but also streamline the manufacturing process; thus, enhancing its potential for broad industrial use.

Optimizing the cell compatibility and mechanical properties in TiZrNbTa medium-entropy alloy/β-Ti composites through phase transformation

Medium-entropy alloys (MEAs) typically exhibit outstanding mechanical properties, but their high Young's modulus results in restricted clinical applications. Mismatched Young's modulus between implant materials and human bones can lead to “stress shielding” effects, leading to implant failure. In contrast, β-Ti alloys demonstrate a lower Young's modulus compared to MEAs, albeit with lower strength. In the present study, based on the bimodal grain size distribution (BGSD) strategy, a series of high-performance TiZrNbTa/Ti composites are obtained by combining TiZrNbTa MEA powders with nano-scale grain sizes and commercially pure Ti (CP-Ti) powders with micro-scale grain sizes. Concurrently, Zr, Nb, and Ta that are β-Ti stabilizer elements diffuse into Ti, inducing an isomorphous transformation in Ti from the high Young's modulus α-Ti phase to the low Young's modulus β-Ti phase at room temperature, optimizing the mechanical biocompatibility. The TiZrNbTa/β-Ti composite demonstrates a yield strength of 1490 ± 83 MPa, ductility of 20.7 % ± 2.9 %, and Young's modulus of 87.6 ± 1.6 GPa. Notably, the yield strength of the TiZrNbTa/β-Ti composite surpasses that of sintered CP-Ti by 2.6-fold, and its ductility outperforms TiZrNbTa MEA by 2.3-fold. The Young's modulus of the TiZrNbTa/β-Ti composite is reduced by 28 % and 36 % compared to sintered CP-Ti and TiZrNbTa MEA, respectively. Additionally, it demonstrates superior biocompatibility compared to CP-Ti plate, sintered CP-Ti, and TiZrNbTa MEA. With a good combination of mechanical properties and biocompatibility, the TiZrNbTa/β-Ti composite exhibits significant potential for clinical applications as metallic biomaterials. Statement of significanceThis work combines TiZrNbTa MEA with nano-grains and commercially pure Ti with micro-grains to fabricate a TiZrNbTa/β-Ti composite with bimodal grain-size, which achieves a yield strength of 1490 ± 83 MPa and a ductility of 20.7 % ± 2.9 %. Adhering to the ISO 10993-5 standard, the TiZrNbTa/β-Ti composite qualifies as a non-cytotoxic material, achieving a Class 0 cytotoxicity rating and demonstrating outstanding biocompatibility akin to commercially pure Ti. Drawing on element diffusion, Zr, Nb, and Ta serve not only as solvent atoms to achieve solid-solution strengthening but also as stabilizers for the transformation of the β-Ti crystal structure. This work offers a novel avenue for designing advanced biomedical Ti alloys with elevated strength and plasticity alongside a reduced Young's modulus.

Manipulating the mechanical strength and thermal conductivity of a Mg–4Zn-0.6Zr alloy through Ca addition

In this study, the microstructure, mechanical properties, and thermal conductivity of as-extruded Mg–4Zn-0.6Zr-xCa (x = 0, 0.3, 0.6, 0.9 wt%) alloys were investigated. The results revealed a bimodal grain size distribution in all the alloys due to incomplete dynamic recrystallization (DRX), characterized by the coexistence of elongated deformed grains and equiaxed DRX grains. The bimodal grain size distribution enhanced the mechanical properties of the studied alloys. Furthermore, Ca alloying facilitated the formation of Ca2Mg6Zn3 phases, through which the DRX extent was also enhanced. The precipitation of secondary phases, along with the increased DRX induced by Ca addition, was beneficial in eliminating the lattice distortion of the alloys, resulting in improved thermal conductivity compared to the Ca-free Mg–4Zn-0.6Zr alloy. The optimum combination of mechanical properties and thermal conductivity was achieved in the Mg–4Zn-0.6Zr-0.6Ca alloy, with yielding strength, ultimate tensile strength, tensile fracture elongation, and thermal conductivity values of 271 MPa, 318 MPa, 17.6 %, and 123.9 W/(m‧K), respectively. This work demonstrates that Mg–Zn–Zr–Ca-based alloys can be developed with high strength and high thermal conductivity, significantly expanding the industrial application of magnesium alloys.

The configuration design of cross-linked CNT networks to realize heterostructure in Cu matrix composite towards prominent mechanical-electrical property synergy

Developing reticular reinforcement and heterogeneous microstructure remains persistent challenges in one-dimensional carbon nanotube (CNT)-Cu system. We herein fabricated dual-heterostructured Cu composite by diazotizing CNT into cross-linked (CL) networks and achieving bimodal grain distribution. The CL-CNT networks uniformly dispersed in Cu matrix, forming strong C–N/O–Cu covalent bonds at the interfaces and effectively retarding grain growth to create ultra-fine grain (UFG) regions around them. The CL-CNT networks/UFG regions, along with the surrounding coarse grain (CG) regions, resulted in a remarkable synergy between mechanical and electrical properties within the composite. Systematic analysis indicates that CL-CNT network acts as a whole to bear loading, remarkably enhances the load-transfer strengthening and promotes the dislocation accumulation around the interface. Meanwhile, hetero-deformation between “hard” CL-CNT networks/UFG regions and “soft” CG regions lead to extra-strengthening and hardening associated with strain partitioning, generation of geometrically necessary dislocation (GND) and strain delocalization. In-situ tensile test further reveals that CL-CNT/Cu with dual-heterostructure introduces the extra-toughening via crack bridging and deflection mechanisms. Besides, CL-CNT network with the robust interface is considered to reduce the interfacial inelastic scattering and provide additional paths for electron transport, accounting for the high electrical conductivity. This work highlights the importance of configuration design of reinforcement in tailoring heterostructured metal matrix composites (MMCs) with outstanding comprehensive performance.

Good strength-ductility synergy achieved in a Fe62Ni16Co9Mn9Ti3Si1 Fe-high-entropy alloy with heterogeneous structures

Developing metal structural materials with a good combination of strength-ductility is of great significance for the rapid development of the aerospace industry and the energy industry. High-entropy alloys (HEAs) have attracted widespread attention due to their excellent mechanical properties, especially the excellent ductility and toughness of face-centered cubic (FCC) high-entropy alloys. However, similar to traditional alloys, there is a trade-off between strength and ductility in HEAs. In this paper, we report the successful preparation of Fe-HEA (Fe62Ni16Co9Mn9Ti3Si1 (atomic percentage, %)) with high strength-ductility synergy at room temperature by cryo-rolling and annealing at 600 °C for 10 min (CR600), which increases the yield strength by 59% compared to room temperature rolling (RR600), while the uniform elongation decreases by only 20%. The ultra-high yield strength and the not significant reduction in uniform elongation are mainly attributed to the formation of high-density dislocations, dual-phase bimodal ultra-fine grain heterostructures, (NiMn)3-xTix and (Fe, Ni)2SiTi composite nanoprecipitates, precipitation-induced chemical composition heterogeneity, and BCC→HCP phase transformation during tensile deformation during CR and subsequent annealing at a reduced temperature (600 °C). In addition, by increasing the annealing temperature of the alloy after CR to 800 °C, its uniform elongation can be increased to 53%, which is mainly due to the excellent strain hardening ability induced by changes in heterogeneous structures, nanoprecipitates, and martensitic phase transformation. Compared with other similar alloys, our CR alloy exhibits higher strength-ductility synergy. The results of this study provide a new perspective for developing HEAs with higher strength-ductility synergy.

Microstructural evolution modelling and low-stress fatigue performance of bimodal-structured Al-Mg-Sc-Zr alloy produced by laser powder bed fusion additive manufacturing

ABSTRACT Coarse – and fine-grained bimodal-structures in a Al-Mg base alloy with rare earth elements of Sc/Zr is produced due to the ultrafast nonequilibrium solidification occurs in laser-induced molten pools during laser powder bed fusion (LPBF) additive manufacturing. A novel high-fidelity cellular automaton (CA) algorithm incorporating numerical calculations of molt-pool temperature fields elucidates the formation and evolution of the bimodal-structure. Subsequent heat treatment induces precipitation of Al3(Sc/Zr) particles within the grains, synergistically enhancing strength and plasticity of the LPBF-processed alloy. The crystal plastic finite element method (CPFEM) is used to reveal the synergistic effect between the strength and plasticity during the material tensile procedure. The bimodal-structure exhibits good fatigue resistance but intriguing anisotropy under low stress cyclic loading. It is proved that differentiated distribution patterns relative to the principal stress direction of the bimodal-structure have a significant influence on its fatigue performance. Numerical evolutionary of the bimodal grain deformation reflects this phenomenon.

Electrochemical characteristic and microstructure of Ti-6Al-7Nb alloy by centrifugal casting for orthopedic implant based on ageing time variations

The alternative Ti-6Al-7Nb alloy has gained extensive progression due to its ability to eliminate the cytotoxicity of vanadium (V) in Ti-6Al-4V alloy for orthopedic implants. The production of titanium alloys by centrifugal casting shows significant potential to reduce costs. Heat treatment and aging can tailor the microstructure and improve the corrosion resistance of titanium alloys. This study examines the effects of various ageing times on the microstructure and corrosion resistance of a centrifugal cast Ti-6Al-7Nb alloy that has previously been heated and treated at a temperature of 1050 °C, and subsequently cooled to room temperature in argon atmosphere gas. Ageing was carried out at a temperature of 550 °C with variable times of 0, 4, 6, and 8 hours. The surface morphology, metal phase changes, and electrochemical characterization were tested using an optical microscope (OM), X-ray diffraction (XRD), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The basket-weave microstructure is formed where globularization occurs in some phases as ageing time increases. Increasing the FWHM α value is correlated with increasing the amount of α' martensite phase. As an ageing time enhances, the temperature might offer a greater driving constrain for the nucleation and expansion of the lamellar phase (α). Ageing of 8 hours has the lowest corrosion rate, 0.0023 mpy and highest corrosion resistance, 90457 Ω∙cm2, due to the partially bimodal structure and grain refinement with a smallest grain size of 327.87 µm. Tafel polarization results show that all passivated samples are stable in the Solution Body Fluid (SBF). This work can be used as a starting point for developing microstructural evolution in titanium alloys