Mn Alloy Research Articles

Effect of bovine serum albumin on immersion corrosion and tribocorrosion behavior of Zn-0.4Mn alloy in simulated body fluid

The related research on the corrosion of degradable Zn-Mn alloy in vitro is not comprehensive. This work investigated the effect of bovine serum albumin (BSA) on corrosion of Zn-Mn alloy in simulated body fluid. The corrosion influence of BSA on the alloy is related to the immersing time. When tribocorrosion occurs, the average depth of frictional wear scratches decreases by 10.7 % and 57.1 % after adding 0.1 g/L and 10 g/L BSA, respectively. It can be further reduced to 68.1 % after applying a voltage of-1.05 V (vs. SCE). This work contributes to degradation control of Zn-Mn alloy implants in vivo.

Biological evaluation of femtosecond-laser-textured Fe–Mn alloys for vascular applications

Biodegradable metals represent a valuable solution for the development of temporary vascular implants. These are expected to dissolve in the body over time, avoiding side effects typical of permanent implants, such as thrombosis, in-stent restenosis and chronic inflammation. Iron (Fe)-based alloys, such as iron–manganese (Mn) alloys, are of particular interest for cardiovascular applications due to their intrinsic properties. However, their degradation behavior and biological performance need to be improved. Femtosecond (fs)-laser-induced surface topography could affect both their degradation and cell–material interaction. In this work, fs-laser-induced patterning was performed on a Fe–Mn20 alloy to tune both the degradation behavior of the material and its interaction with the biological environment for cardiovascular applications. Processing parameters were varied to select an optimized surface morphology, characterized by linear grooves. Profilometric analysis, scanning electron microscopy and degradation rate analysis were performed on the treated samples. Thereafter, endothelial cell viability tests and hemocompatibility assessment were carried out on selected process conditions. The obtained fs-laser-induced linear patterns were demonstrated to decrease the degradation rate and to improve the biological response toward both endothelial cells and blood. These results demonstrate how fs-laser-induced patterning is a promising solution for the development of biodegradable metal-based vascular implants.

Enhancement mechanism of low alloying (Mn, Al) and plastic deformation for hydrogen storage kinetics of Mg alloy

The sluggish kinetics are a momentous hurdle for the application of Mg-based hydrogen storage alloys. To improve the kinetics, Mg-xMn-0.5Al alloys (x = 0, 0.5, 1, 2) were fabricated by combining low alloying strategy and plastic deformation. The results demonstrate that both low alloying and plastic deformation enhance the kinetic properties of hydrogen adsorption and desorption. The resulting Mg-2Mn-0.5Al alloy after plastic deformation can absorb ca. 5 wt% hydrogen within 3 min at 623 K, and the dehydrogenation activation energy (ca. 125 kJ/mol) is substantially reduced versus Mg (ca. 166 kJ/mol). The co-addition of Mn and Al can introduce more second phases, and the pinning effect of Al8Mn5 and α-Mn on grain boundaries can promote grain refinement and dislocation proliferation. The increase of grain boundaries, phase interfaces and dislocations accelerates the H atoms diffusion, benefitting the hydrogen absorption. Plastic deformation generates plenty of nanoscaled Al8Mn5 particles, which can serve as additional heterogeneous nucleation sites of Mg during dehydrogenation. Low alloying of Mn and Al combined with plastic deformation is a low-cost and effective way to improve the hydrogen storage kinetics of Mg-based alloys.

The anodic dissolution kinetics of Mg alloys in water based on ab initio molecular dynamics simulations

AbstractThe corrosion susceptibility of magnesium (Mg) alloys presents a significant challenge for their broad application. Although there have been extensive experimental and theoretical investigations, the corrosion mechanisms of Mg alloys are still unclear, especially the anodic dissolution process. Here, a thorough theoretical investigation based on ab initio molecular dynamics and metadynamics simulations has been conducted to clarify the underlying corrosion mechanism of Mg anode and propose effective strategies for enhancing corrosion resistance. Through comprehensive analyses of interfacial structures and equilibrium potentials for Mg(0001)/H2O interface models with different water thicknesses, the Mg(0001)/72 H2O model is identified to be reasonable with −2.17 V vs. standard hydrogen electrode equilibrium potential. In addition, utilizing metadynamics, the free energy barrier for Mg dissolution is calculated to be 0.835 eV, enabling the theoretical determination of anodic polarization curves for pure Mg that aligns well with experimental data. Based on the Mg(0001)/72 H2O model, we further explore the effects of various alloying elements on anodic corrosion resistance, among which Al and Mn alloying elements are found to enhance corrosion resistance of Mg. This study provides valuable atomic‐scale insights into the corrosion mechanism of magnesium alloys, offering theoretical guidance for developing novel corrosion‐resistant Mg alloys.

The microstructure evolution and strengthening mechanism of fine-grained Al–Mn alloy with nanoscale precipitates during cryorolling

In this work, the fine-grained Al–Mn alloys with nanoscale precipitates was designed, and the texture evolution and strengthening mechanism for fine-grained Al–Mn alloy with nanoscale precipitates during cryorolling were investigated by EBSD and TEM analysis. The results show that the dislocation tangles gradually evolved into dislocation cells, and then into subgrains/ultrafine grains with boosting rolling reduction. The initial grains and precipitates can be significantly refined by cryorolling. Furthermore, the dominating P and M textures in the solution-treated Al–Mn alloy gradually converted to α-fiber and β-fiber textures during cryorolling. The formation of α-fiber and β-fiber textures is beneficial for improving the strength of the Al–Mn alloy. An excellent strength-ductility synchronization can be achieved in the Al–Mn alloy cryorolled at a rolling reduction of 50 %. The strengthening mechanism of Al–Mn alloy subjected to cryorolling is associated with texture strengthening, dislocation strengthening, grain refinement strengthening and precipitation strengthening.

SiC nanoparticles additions to squeeze-cast Mg-5.0Al-2.0Ca-0.3Mn alloy: An evaluation of microstructure and mechanical properties

The influences of the SiC nanoparticles (SiCnp) content on the microstructural modification and mechanical properties of the squeeze-cast Mg-5.0Al-2.0Ca-0.3Mn (AXM520) alloy have been investigated. The concentrations of the SiCnp are varied from 0.5 to 3.0 (wt%), and the nanocomposites (NCs) are abbreviated as NC0.5SiC, NC1.0SiC, NC2.0SiC and NC3.0SiC. The as-cast microstructures of the AXM520 alloy and NCs consist of an α-Mg phase, a eutectic of α-Mg and (Mg,Al)2Ca (C36), and an Al8Mn5 phase. Additionally, the SiC phase is also present in the NCs. The continuous network of the C36 phase is fragmented and becomes discontinuous as the content of the SiCnp increases in the NCs. All the NCs exhibit superior tensile and compressive properties than the AXM520 alloy. The NC2.0SiC exhibits the best tensile properties among the NCs employed. The YS of the NCs improves with the increase in the SiCnp content up to 3.0 (wt%). The UTS and %El of the NCs increase up to 2.0SiCnp (wt%), and beyond that, the same declines owing to the agglomeration of the nanoparticles. The discontinuous network of the C36 phase in the NCs inhibits crack propagation, leading to their improved %El. All the NCs exhibit higher strain-hardening exponent (n) and strain-hardening rate (SHR) compared to the AXM520 alloy. The superior ‘n’ and SHR exhibited by the NCs were attributed to the grain refinement and dislocations generation. The strengthening from CTE mismatch contributes the most to the overall strengthening of the NCs. The ‘Zhang and Chen’ model is modified by introducing an agglomeration factor, and the predicted YS of the NCs matches pretty well with the experimentally obtained values.

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.

The Effect of Extrusion Ratio on the Discharge and Corrosion Behavior of Mg-3Al-2.8Y-0.7Mn Alloy

The Effect of Extrusion Ratio on the Discharge and Corrosion Behavior of Mg-3Al-2.8Y-0.7Mn Alloy

Effect of CaB6 addition on the microstructure and mechanical properties of Ti–24Nb–4Zr-2.5Mn alloys fabricated by spark plasma sintering

Balancing the strength, ductility and Elastic modulus of β-Ti alloys is still a great challenge for medical implantation, extremely limiting its further applications. Herein, we prepared a fine-grain β-type Ti–24Nb–4Zr-2.5Mn alloy with high performance by adding CaB6 deoxidizer via mechanical alloying and spark plasma sintering. The effects of CaB6 addition on the microstructure and mechanical properties were systematically investigated, and the results show that adding a trace amount of CaB6 will form in-situ nano-sized CaTiO3 particles and micro-sized (Ti,Nb)B2 solid solution whiskers, which can significantly refine the grain size and inhibit the grain boundary movement and dislocation motion, thus improving the comprehensive mechanical properties of Ti–24Nb–4Zr-2.5Mn alloys. With a trace addition of 0.1 wt% CaB6, the Ti–24Nb–4Zr-2.5Mn alloy exhibits an excellent combination of high strength of ∼971 MPa, good ductility of ∼17.8% and low elastic modulus of ∼79.1 GPa. This work may provide a new methodology to prepare high-performance biomedical Ti alloys.

Effect of rolling temperature on microstructure and mechanical properties of hot-rolled Mg-Al-Ca-Zn-Mn alloys

In order to address the problems of traditional magnesium alloys, such as the easy formation of basal texture and poor plasticity at room temperature, a multivariate micro alloyed Mg-1Al-0.9Ca-0.5Zn-0.4Mn material has been designed by taking advantage of the unique role of solute atoms such as Ca. The effects of its rolling process on grain size, second phase, texture, and tensile properties were compared and analyzed. The results show that the rolling temperature will significantly change the organization and properties: a small number of large-sized reticulate phases, linear phases, and granular phases will exist along the rolling direction inside the Mg-1Al-0.9Ca-0.5Zn-0.4Mn alloy. When the rolling temperature is raised, it will change the number and size of the second phase and microstructure morphology. For three plates rolled at 300°C, the best-combined strength-plasticity mechanical properties were presented in this work; elongation is 2.5%, tensile strength is 167 MPa, and yield strength is 146 MPa along the RD, respectively. Besides, some larger-sized phases still exist in this alloy, which affects its mechanical properties.

Development of novel low density ultra-high strength manganese-steel with significant ductility through thermo-mechanical processing route

The development of ultra-high strength steels for automotive applications is often associated with insufficient ductility or formability properties. To overcome this problem, a high Mn alloy steel (Fe–15Mn-0.17C–2Al–3Si-0.6Ti) was prepared by induction melting and was subjected to various thermomechanical treatments (TMT) to achieve high strength with high ductility. The TMT comprised of simply hot forging (at 1373K) and hot rolling at three different temperatures (1073K, 1173K, and 1273K) followed by water quenching. The forged steel displayed a tensile strength of 510 MPa with 34 % elongation, while the hot-rolled steel (at 1173K) demonstrated a remarkable improvement in both strength (approximately 2 GPa) and ductility (around 51 % elongation). The microstructure of the rolled steel showed austenite, α-ferrite, and precipitates of TiAl; the austenite was found to possess finer grain size (∼7.9 μm) with a significant amount of twins (volume fraction = 32 %). The high strength was achieved due to finer grain size, higher amount of twins, transformation-induced martensite, and precipitation hardening, while the substantial ductility was attributed to significant TWIP and TRIP effect.

Controlling the Fe-intermetallic phases and mechanical properties of secondary Al-9Si-1Fe alloy with Cr and Mn additions

In secondary Al-Si based alloys, microalloying with Mn and Cr can modify harmful platelet-type AlxFeySiz intermetallic phases to less detrimental α-Alx(Fe, Mn, Cr)ySiz phase (script or polygonal morphologies). However, the α-Alx(Fe, Mn, Cr)ySiz phase morphology, phase composition and the addition of Fe-correcting elements can be influenced by solidification conditions. Therefore, this research is aimed to highlight the morphological evolution and mechanisms of α-Alx(Fe, Mn, Cr)ySiz phase in a Cr added Al-9 %Si-1 %Fe-0.2 %Cr (all weight percentage thereafter, unless otherwise stated) alloy with varying Mn concentrations (0.25 %, 0.5 %, and 0.8 %). Microstructure evolution of Fe intermetallic phases is investigated under different casting conditions using a wedge-shaped die, Cu-chill block and melt quenching experiments. Thermodynamic simulations have been performed using CALculation of PHAse Diagrams (CALPHAD) method and compared with the experimental results for phase composition and formation temperatures of α-Alx(Fe, Mn, Cr)ySiz phase. The results indicated that for 0.25Mn-0.2Cr addition to Al-9Si-1Fe alloy, compact morphology containing polygonal phases are formed in Cu-chill casting, while the wedge castings predominantly show a mixed structure with platelets and script type morphologies. Tensile tests revealed a higher elongation value of 6.6 % for mixed structure with platelet and script phases, which is decreased to 4.2 % for polygonal phases in Al-9Si-1Fe-0.2Cr-0.25Mn alloy. This study highlights the importance of solidification conditions on morphologies of Fe-intermetallic phases and the mechanical properties by comparing selected literature relevant to high pressure die-casting process.

Thermal stability of refined Al6(Fe, Mn) phase formed in laser powder bed fusion process

The addition of Mn in Al–Fe alloys stabilizes the Al6Fe metastable phase (orthorhombic structure, oC28) owing to the partial occupation of Fe sublattice sites by Mn atoms (formation of Al6(Fe, Mn) phase), thereby achieving superior high-temperature strength of Al–Fe–Mn ternary alloys that are manufactured via laser powder bed fusion (L-PBF) process. This study aimed to fundamentally understand the thermal stability of the refined Al6(Fe, Mn) phase formed in the L-PBF fabricated Al–2.5%Fe–2%Mn alloy in terms of a thermodynamic approach and the kinetics of morphological changes in the Al6(Fe, Mn) phase at elevated temperatures ranging from 200 to 500 ℃. The L-PBF processed samples showed a high hardness of approximately 125 HV due to the formation of numerous dispersoids of the Al6(Fe, Mn) phase with sizes of several tens of nanometers in the α-Al matrix containing concentrated solute elements of Fe and Mn. The hardness and microstructure were almost unchanged even after exposure to a high temperature of 200 ℃ for an extended period of 1000 h. Upon exposure to 300 ℃, nucleation and growth of the Al6(Fe, Mn) phase occurred locally, particularly at grain boundaries in the α-Al matrix. Such a local growth contributed to a reduction in hardness upon thermal exposure. Simultaneously, numerous nanoscale precipitates were formed in the α-Al matrix, resulting in a suppressed reduction in hardness. Contrary to the result of the thermodynamic calculations, the θ-Al13Fe4 phase was scarcely found even after long-term exposure to 500 ℃. The θ-phase formation was accompanied by the dissolution of the refined Al6Fe metastable phase for strengthening, which significantly reduced the hardness during thermal exposure. The suppressed θ-phase formation could be associated with the thermodynamically stable Al6(Fe, Mn) phase developed during the L-PBF process, which predominantly contributed to the high microstructural stability of the L-PBF fabricated Al–Fe–Mn alloy at elevated temperatures.

Study on hydrogen storage properties of Ti–V–Fe–Mn alloys by modifying Ti/V ratio

The high stability of hydride phase has limited the improvement for the hydrogen storage properties of Ti–V based alloy at room temperatures. In this work, the stability of hydride was reduced by designing a low-price Ti–V–Fe–Mn alloy, and the effect of Ti/V ratio on the crystal structure and hydrogen storage properties was systematically investigated. The Ti40-xV40+xFe15Mn5 (x = 0, 2, 4, 6, 8) alloys were synthesized using arc melting, and the as-prepared alloys are all composed of single BCC phase. The lattice constant and cell volume decrease linearly with a lessening in Ti/V ratio. The reduction of cell volume makes it difficult for hydrogen atoms to diffuse, resulting in a sluggish hydrogen absorption rate. The dehydrogenation plateau in PCI curve rises and corresponding thermodynamics is optimized with a decrease in the lattice constant, and the hydrogen atoms are more readily to release, especially for Ti32V48Fe15Mn5 alloy with the dehydrogenation capacity of 1.83 wt% at 373 K. The result indicates the thermodynamic properties can be optimized by adjusting the lattice constant of Ti–V–Fe–Mn alloys, and hydrogen storage capacity is improved effectively. This study provides a reference for composition design of Ti–V–Fe–Mn alloys for high-density hydrogen storage.

Tailoring properties of directed energy deposited Al-Mg alloy by balancing laser shock peening and heat treatment

Wire arc-directed energy deposition (WADED) has shown great advantages and potential in fabricating large-scale aluminum (Al) alloy components. However, WADED Al alloys typically exhibit low strength and reliability due to pore defects and lack of work hardening or precipitation strengthening. This study utilized a combination of laser shock peening (LSP) and annealing to regulate the microstructure of WADED Al-Mg4.5Mn alloy and enhance mechanical properties. The effects of LSP and annealing on phase composition, pore distribution, and microstructures at multiple scales were systematically investigated to reveal the mechanical property improving mechanism. The results demonstrated that LSP-induced plastic deformation formed a defect-free zone by closing near-surface pore defects. LSP created the hardened layer with gradient mechanical properties by inducing gradient changes in grain size, the number of low-angle grain boundaries (LAGBs), and dislocation density along the depth direction. The annealing process promoted grain coarsening and reduced excessive dislocations and LAGBs, weakening the work hardening effect caused by LSP. Furthermore, the high-density dislocations and high stored energy generated by LSP accelerated the recrystallization, facilitating growth of near-surface grains. The defect-free zone, dislocation strengthening, and LAGBs strengthening were responsible for the increase in strength, while the synergistic deformation between hardened layers and soft core facilitated maintaining excellent elongation. The strength and elongation of WADED Al alloy can be synergistically improved by balancing the effects of LSP and heat treatment.

Achieving high strength and high elasticity of Cu–Ni–Cr–Mn alloy by synergistic effect of multi-scale precipitates

The microstructural evolution, precipitation behavior and mechanical properties of Cu–19Ni–6Cr-xMn (x=0, 1, 3, 5, 7, 9 wt%) alloys were examined in the presence of solution treatment, cold rolled treatment and aged treatment. The results show that aged Cu–19Ni–6Cr–7Mn alloy exhibits superior mechanical properties with a hardness of 379 HV, tensile strength of 1012 MPa, and elastic modulus of 149.5 GPa, which is the maximum reported value for elastic modulus of copper alloys. The Mn element promotes the uniform distribution of the precipitates and grain refinement. Thermodynamic calculations indicate that the formation of the NiMn precipitates takes precedence over the NiCr-rich precipitates in this alloy. Three typical precipitates were detected in the Cu–19Ni–6Cr–7Mn alloy, including submicron-sized Cr-rich precipitates (>500 nm), nano-sized bcc-Cr precipitates (30–70 nm), and nano-sized NiMn precipitates with L12 ordered structure (3–5 nm). Precipitation plays a major role in improving the strength of the alloy. The synergistic effect between multi-scale precipitates, high-density dislocations, and solution strengthening has achieved significant breakthroughs in mechanical properties which open up new possibilities for engineering applications requiring high-strength and high-elasticity copper alloys.

The effect of Sn microalloying on the selective oxidation of Fe-(6-10 at.%)Mn alloys

To evaluate the suitability of Sn microalloying as strategy to decrease the selective oxidation kinetics of Mn-alloyed advanced steels, the effects of 0.01 and 0.03 at.% Sn micro-additions on oxide morphology and oxidation kinetics for Fe-6Mn and Fe-10Mn (at.%) alloys were determined under annealing conditions characteristic of the continuous galvanizing process. Selective oxidation followed a parabolic rate law, where activation energy analysis revealed that internal oxidation is rate-determined by the grain boundary diffusion of O in Fe. The 0.01 and 0.03 at.% Sn additions significantly reduced the internal oxidation of alloys with Mn contents of 6 and 10 at.%, which was attributed to interfacial Sn segregation reducing the solubility of O in Fe, the occupation of adsorption sites for water vapour molecules, and the reduction of short-circuit diffusion of O along internal interfaces. Sn microalloying decreased the external oxidation of Fe-6Mn-(0.01,0.03)Sn, but did not significantly alter external oxide thickness of the Fe-10Mn-(0.01,0.03)Sn alloys. In this case, Sn reduced the outward diffusion of Mn along grain boundaries, but also affected the balance between the inward O flux and outward Mn flux. Incorporating the effect of Sn occupying adsorption sites into a selective oxidation model revealed that Sn microalloying is predicted to cause a transition from internal to external oxidation for Fe-10Mn. For Fe-6Mn alloys, however, a Sn micro-addition of 0.01 at.% (∼0.022 wt.%) was sufficient to significantly reduce selective oxidation kinetics and produce beneficial alterations to the external oxide morphology in order to ease reactive wetting in the continuous galvanizing process.

Effect of Cu addition on the mechanical properties and corrosion behaviours of Al–9.2Mg–0.8Mn alloy

Microalloying is an effective method to improve the properties of Al–Mg alloys. The microstructure, mechanical properties and corrosion behaviours of Al–9.2Mg–0.8Mn– xCu ( x = 0–1.2 wt-%) alloys are studied to promote the application of Al–Mg alloys. The addition of Cu increases the strength of the alloy, where the ultimate tensile strength of 0.6 wt-% Cu alloy is improved by 43 MPa. Moreover, the addition of Cu significantly affects the corrosion behaviours of alloys. For as-sensitised alloys, compared to the matrix, the 0.1 wt-% Cu alloy shows a 28.3% reduction in pitting corrosion mass loss, which is attributed to the Cu element can form a stable passivation film, and the 0.3 wt-% Cu alloy shows a 15% reduction in intergranular corrosion mass loss, which is attributed to the addition of Cu can restrict the β phase precipitation at grain boundaries. The study shows that Cu-alloying can improve the comprehensive properties of Al–9.2Mg–0.8Mn alloys.

Effect of extrusion temperature on microstructure and mechanical properties of ZTM631 magnesium alloy

Magnesium alloys are widely used in the fields of aviation, electronics, and automotive manufacturing due to their advantages of lightweight and high specific strength. Studying high-performance and low-cost deformed magnesium alloys to adapt to more application scenarios has important value. In the present work, the effect of extrusion temperature on the microstructure and mechanical properties of Mg-6Zn-3Sn-0.9Mn (ZTM631) alloy was investigated. Besides, the ultra-high cycle fatigue (VHCF) performance and fatigue failure mechanism of ZTM631 alloy was explored. Results show that extrusion temperature significantly affect the microstructure of ZTM631 alloys. Firstly, alloys extruded at 300℃ possess a relatively fine grain size, because the lower extrusion temperature prevent the grain growth. Secondly, phases precipitate at 300°C and 350°C with a large size (more than 1 µm) are mainly α-Mn phase. while for the alloys extruded at 400°C, both α-Mn and Mg2Sn phases with the size larger than 1 µm can be found in the matrix. Thirdly, alloys extruded at 400℃ exhibit the best mechanical properties, due to the combination of the grain refinement and precipitation strengthening. Fourthly, during the VHCF failure process, the crack preferentially generates at the densely distributed α-Mn phases for the alloy extruded at 300°C and 350°C, while the crack initiate near the Mg2Sn particles for the alloy extruded at 400°C. Also, undynamic recrystallized (un-DRXed) grains with severe deformation exist in the alloys extruded at 300℃ and 350℃, thus accelerating the crack initiation. This fundamental investigation provides theoretical information for developing high-performance Mg-Zn-Sn alloys with high strength and expanded their application fields.

Enhancing the recrystallization resistance and strength-ductility trade-off of Al–Mg–Si–Cu–Mn alloys by three-step homogenization

This study explores a three-step homogenization regime tailored to optimize the dispersoids precipitation, recrystallization resistance, and consequently, the mechanical performance of an Al–Mg–Si–Cu–Mn alloy. Comparative analyses against conventional one-step homogenization treatment reveal a substantial improvement in the precipitation of α-Al(Mn,Fe)Si dispersoids, with a 77.2% increase in number density and a 9.1% reduction in average size. This enhancement is attributed to the optimized nucleation kinetics achieved at an intermediate temperature during the three-step homogenization process. Samples subjected to one-step homogenization treatment experience complete recrystallization after a 1 h solution treatment at 560 °C, whereas three-step homogenized samples exhibit superior resistance to recrystallization, maintaining a well-preserved recovery structure. Pinning force analysis highlights the enhanced effectiveness of dispersoids obtained with the three-step homogenization treatment in inhibiting recrystallization. In terms of mechanical performance, samples underwent the three-step homogenization treatment demonstrate a synergistic enhancement in strength and ductility compared to the one-step homogenized sample. This enhancement is attributed to the intergranular fracture and low working hardening rate induced by the large recrystallized grains present in the samples treated with one-step homogenization.