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Pb-Co anodes have been considered an attractive candidate for oxygen evolution reaction (OER) applications due to their low overpotential to catalyze the OER and its low cost. Despite these characteristics, their efficiency to produce oxygen at high current densities is low. In this work, we report a Pb-Co-Sn film with enhanced efficiency and improved electrocatalytic properties. Pulsed cathodic electrodeposition was used to develop Pb-Co-Sn films at different deposition times among 2 and 10 min. Polarization curves were recorded to determine the deposition parameters. Morphological studies showed that the films grown for 6 min exhibited a well-covered and homogeneous surface. Structural analyses were recorded employing X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) that showed a nanostructured film composed by Pb and CoSn2 nanocrystallites. The electrochemical behavior of the developed Pb-Co-Sn films was measured by polarization curves in a sulfuric acid solution demonstrating a great ability to catalyze the OER: a reduction of the overpotential by 55% and 8.5% versus a Pb-Ca-Sn anode and Pb-Co film, respectively, accompanied by a strong increase in the current density. Thus, the addition of tin to the anode has a positive effect on the electrocatalytic performance of the film.

Mg-Zn-Zr (ZK) alloys exhibit notably high mechanical strength amongst all magnesium alloy grades. However, due to the formation of low melting point Mg3Zn7-precipitates, these alloys are susceptible to hot cracking, thus compromising their metallurgical processing. The addition of rare earths to ZK alloys is an alternative to form higher melting point intermetallic compounds, speed up dynamic recrystallization, refine grain size, enhance corrosion resistance and extend the service temperature due to improved creep resistance. This work deals with the effect of Ce-base mischmetal addition on the hot rolling behaviour of as-cast ZK60 alloy. The microstructure investigation conducted using electron microscopy and X-Ray diffraction shows that precipitation of Mg7Zn3 intermetallics occur during hot rolling, whereas no further precipitation is observed for the ZK60-Mm alloys. The fragmentation of the intermetallic compounds occur during hot rolling and finer particles of Mg7Zn3 are observed for the ZK60, whereas Mg7Zn3 and MgZn2Ce intermetallics are formed in the alloy modified with mischmetal addition. A higher fraction of dynamically recrystallized grains is observed for the ZK60-Mm in comparison to the ZK60. Continuous recrystallization takes place in ZK60 with the formation of sub-grains near to the intermetallics and the addition of mischmetal promotes the occurrence of discontinuous recrystallization with the nucleation of new grains close to the precipitates. The mechanical strength and, in particular, the ductility of the hot-rolled alloys are notably improved when compared to the same alloys in the as-cast condition. The mechanical strength is, however, higher for the ZK60 alloy. Less solid solution strengthening, softer MgZn2Ce intermetallics and more extensive recrystallization contribute to reduce the mechanical strength of ZK60-Mm. Failure in both alloys are initiated at coarse intermetallics and propagate through intermetallic-rich regions.

Journal of magnesium and alloys 9(5), 1782-1796 (2021). doi:10.1016/j.jma.2021.04.012, Published by Elsevier, Amsterdam [u.a.]

The low carbon martensitic stainless AWS 410NiMo steel has in its chemical composition 13% chromium, 4% nickel, and 0.4% molybdenum (wt.%) and is used in turbine recovery, rotors, and high-pressure steam pump housings due to its resistance to impact at low temperatures, as well as to corrosion and cavitation. Those applications of the AWS 410NiMo steel frequently demand repair, which is performed by welding or cladding. Arc welding is a well-established technique for joining materials and presents several parameters that influence the mechanical performance of the weld bead. Although numerous welding processes exist, optimizing welding parameters for specific applications and materials is always challenging. The present work deals with a systematic study to verify the correlation between the pulsed fluxed core arc welding (FCAW) parameters, namely pulse current and frequency, welding speed, and contact tip work distance (CTWD), and the bead morphology, microstructure formation, residual stress, and hardness of the martensitic clad. The substrate used was the AISI 1020 steel, and the AWS 410NiMo steel was the filler metal for clad deposition. From the initial nine (9) samples, three (3) were selected for in-depth characterization. Lower heat input resulted in lower dilution, more elevated hardness, and lower compressive residual stresses. Therefore, the results highlight the need for selecting the proper heat input, even when using a pulsed FCAW procedure, to achieve the desired performance of the clad. In the present case, a higher heat input appears to be more advantageous owing to the lower convexity index, smooth hardness transition between fusion and heat-affected zones in addition to more elevated compressive stresses.

Magnesium alloys are important alternatives for structural weight reduction due to their low density and good specific mechanical strength. Among the magnesium alloys, the ZK type exhibits the highest mechanical strength. However, it has limitations on hot working or welding owing to the presence of intermetallics with low melting point and consequently susceptibility to hot crack formation. The addition of rare earths tends to form intermetallics with higher melting points, thus inhibiting the formation of hot cracks, as well as building up thin and dense surface films that improve corrosion resistance. This work studies the addition of 1.5% wt. of mischmetal (Mm) to the ZK60 alloy, and then demonstrates the effects of the casting process with mechanical mixing in the semi-solid state. The alloys produced were: ZK60 and ZK60–1.5 wt%Mm manufactured by conventional casting and rheocast ZK60–1.5 wt%Mm produced with mechanical mixing in the semi-solid state. The casting and cooling methods result in defect-free and chemically homogeneous materials, and the mechanical mixing provides a homogeneous microstructure with globular grains. The mechanical strength was though higher for the ZK60 alloy due to its increased solute content within the Mg-matrix and the smaller quantity of intermetallics that builds up an intermittent network. The Mg7Zn3 intermetallic, which is the main precipitate for ZK60 alloy, has hardness 20% higher than the MgZn2Ce intermetallic that is precipitated with the mischmetal addition and partly removes solute from the Mg-solid solution.

The cladding welding analysis with pulsed flux cored arc welding (FCAW) process, were carried over a AISI 1020 base metal (thickness 12,7 mm, width 63,5 and length 185mm) with an CA6NM steel wire with diameter of 1.2mm. Was performed only one weld cord in the flat position. For experimental design was used the method of Taguchi L9 to determinate the parameter to be analyzed through the application of the analysis of variance (ANOVA) method. The response signals in RMS (Root Mean Square) analyzed were the voltage, current and acceleration. The procedure is based on a non-parametric domain-selective ANOVA for functional data, which results in the selection of the intervals of the domain presenting the most statistically significant effects of each factor over the selected response signals. The statistical results presented by ANOVA show that not all the selected variables have influenced the results. The best results for the cladding welding were obtained from the current average of230amperes, and statistically the average current was the variable that significantly affected the results, however, the welding speed only affected the yield of the process.

In this study, a commercial Mg-based ZK60 alloy was modified with 2.5 wt% mischmetal (ZK60-2.5 wt%Mm) and further processed by cold rolling followed by manual filing. The chips obtained by manual filing process were collected from the as cast (AC) and the cold rolled (CR) materials. The hydrogen storage properties were evaluated by kinetics measurements at 350 °C. A full microstructural characterization including optical, scanning and transmission electron microscopy (MO, MEV and TEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) was performed in the samples. For the first absorption of both filed samples the H storage capacity showed a value around 6.0 wt% after 1 h while for the CR sample it was close to 1.25 wt% after the same time. The manual filing produced samples with higher hydrogenation kinetics compared with that of the CR sample. Besides, their hydrogen storage capacity was maintained close to the theoretical value (6.75 wt%). The breakage and pulverization of the intermetallic phases gave the chips from the CR alloy the faster hydrogenation kinetics, especially for H-desorption.

Due to their applicability for manufacturing dense, hard and stable coatings, Physical Vapor Deposition (PVD) techniques, such as High Power Impulse Magnetron Sputtering (HiPIMS), are currently used to deposit transition metal nitrides for tribological applications. Cr-Al-N is one of the most promising ceramic coating systems owing to its remarkable mechanical and tribological properties along with excellent corrosion resistance and high-temperature stability. This work explores the possibility of further improving Cr-Al-N coatings by modulation of its microstructure. Multilayer-like Cr1−xAlxN single films were manufactured using the angular oscillation of the substrate surface during HiPIMS. The sputtering process was accomplished using pulse frequencies ranging from 200 to 500 Hz and the resulting films were evaluated with respect to their hardness, Young’s modulus, residual stresses, deposition rate, crystallite size, crystallographic texture, coating morphology, chemical composition, and surface roughness. The multilayer-like structure, with periodicities ranging from 250 to 550 nm, were found associated with misorientation gradients and small-angle grain boundaries along the columnar grains, rather than mesoscopic chemical modulation of the microstructure. This minute modification of microstructure along with associated compressive residual stresses are concluded to explain the increased hardness ranging from 25 to 30 GPa, which is at least 20% over that expected for a film of the same chemical composition grown by a conventional PVD processing route.

Light weighting has been a key issue to meet stringent requirements on greenhouse gas emissions. One possible way of weight reduction is the substitution of heavier components with lighter metals like Magnesium. In this work, the internal architecture of cast and hot rolled ZK60 alloys with and without addition of 1.5 wt% rare earth metals (RE) has been investigated. The alloys were produced by permanent mould indirect chill cast (PMICC), while the material with 1.5 wt% RE was manufactured by additional rheocasting (RC). A multi-resolution procedure using X-ray computed tomography (XCT) was performed to investigate the alloys in size ranges from meso- (cast blocks) to micro-scale (microstructure). The voxel resolutions used were between (115 μm)3 down to (0.8 μm)3. Morphometric parameters such as volume, volume fraction, connectivity, structure separation, structure thickness etc. were calculated to characterize the 3D-microstructure of the various alloys. The alloys showed no detectable cracks in the as-cast condition, while macroscopic defects such as clusters of high-density Zr-rich particles as well as casting pores were identified. The Zr-rich particles as well as other primary intermetallic phases tended to agglomerate at the bottom of the ingots for all investigated alloys. The addition of RE increased the homogeneity of the microstructure in terms of spatial distribution as well as the global and local interconnectivities of intermetallic phases in the PMICC alloy. RC achieved a more homogeneous distribution of Zr-rich particles. Furthermore, RC led to changes of the solidification topology and increased the distance between the higher-density phases. Hot rolling reduced the fraction of pores formed during the casting process. However, pores were not detected in the ZK60 PMICC alloys after forming, while ZK60 + 1.5 wt% RE PMICC and RC showed the presence of voids that were not completely removed by hot rolling until the thickness was reduced about 60%.

Solution treatments (T4) at 380 °C for 16 h and 500 °C for 8 h were performed for ZK60 magnesium alloys modified with addition of 0.5, 1.5 and 2.5 wt% of mischmetal (combination of rare-earth (RE) elements). The compression behaviour was investigated at room temperature and at 300 °C correlated with the microstructure and differential scanning calorimetry (DSC) data. The as-cast microstructure is formed by a-Mg matrix with globular grains reinforced by a semi continuous network of Mg-Zn, Mg-Zn-RE and Mg-RE intermetallic particles. Solution-treated alloys show lower yield strengths due to partial dissolution of precipitates. Work hardening was not observed for the alloys compressed at 300°C with the compression speed of 10-3 s-1, whereas it was observed for the compression speed of 10-2 s-1 for the all as-cast, ZK60-1.5RE-T4 at 380 °C and ZK60-1.5RE-T4 at 380 °C.

The microstructure and mechanical properties of dissimilar butt-joints between a high-strength low alloyed (HSLA) grade and an austenitic high Mn TRIP steel were investigated. The tool rotation and the tool offset toward the TRIP steel were varied between 300–500 rpm and 1–2 mm, respectively. Tool advancing speed amounted to 100 mm/min. Maximum tension stress was observed for the butt-joint welded with 300 rpm and 2 mm offset. The lowest increase in hardness within the stirred zone also occurred for this FSW condition, indicating that this tool rotation is more promising for welding dissimilar joints of commercial HSLA and high Mn TRIP steels. The weld microstructure consisted mainly of a stirred zone, and neither significant HAZ nor TMAZ are observed. However, two main lobular regions are observed, one at the bottom and another one at the top side of the welds. Besides, the HSLA develops a multiphase microstructure consisting of bainite, martensite and retained austenite phases, whereas no e/a martensite is found in the stirred zone of the austenitic high-Mn TRIP steel.

The deformation behaviour of as-cast ZK40 alloys modified with individual additions of Ca and Gd is investigated at 250 &deg, C and 300 &deg, C. Compression tests were carried out at 0.0001 s&minus, 1 and 0.001 s&minus, 1 using a modified Gleeble system during in-situ synchrotron radiation diffraction experiments. The deformation mechanisms are corroborated by post-mortem investigations using scanning electron microscopy combined with electron backscattered diffraction measurements. The restoration mechanisms in &alpha, Mg are listed as follows: the formation of misorientation spread within &alpha, Mg, the formation of low angle grain boundaries via dynamic recovery, twinning, as well as dynamic recrystallisation. The Gd and Ca additions increase the flow stress of the ZK40, which is more evident at 0.001 s&minus, 1 and 300 &deg, C. Dynamic recovery is the predominant restoration mechanism in all alloys. Continuous dynamic recrystallisation only occurs in the ZK40 at 250 &deg, C, competing with discontinuous dynamic recrystallisation. Discontinuous dynamic recrystallisation occurs for the ZK40 and ZK40-Gd. The Ca addition hinders discontinuous dynamic recrystallisation for the investigated temperatures and up to the local achieved strain. Gd addition forms a semi-continuous network of intermetallic compounds along the grain boundaries that withstand the load until their fragmentation, retarding discontinuous dynamic recrystallisation.

As-cast ZK40 alloys, modified with the addition of CaO, Gd, Nd and Y were investigated. Solution heat treatments were performed based on differential thermal analysis results. The unmodified ZK40 alloy exhibited microstructure with nearly no intermetallic compound but with precipitates formed during the solution treatment. The modified ZK40 alloys exhibited a semi-dissolved network of intermetallic compounds along the grain boundaries and zones of intermetallic compounds within the grains. Interestingly, no precipitates were observed immediately next to the grain boundaries. The energy dispersive X-ray spectroscopy line scans showed an enrichment of Zn and Zr in the regions where the precipitates are found, suggesting that they are Zn-Zr precipitates. The ageing behaviour was compared between the as-cast and the solution treated materials and it was found that apart from the ZK40-Gd, ZK40-Nd and ZK40-Y aged at 200 °C after solution treatment, there is no notable ageing response for the investigated alloys.

In this paper we report the use of a novel processing route to produce samples for use as a hydrogen carrier. ZK60 alloy was produced by induction melting and sheets taken from the melt ingot were submitted to Friction Stir Processing (FSP) and subsequent manual filing with a rasp under ambient conditions. Samples from the Base Metal As-Cast (AC) and Stir Zone (SZ) were microstructurally investigated before and after filing including the alloy in as-cast state. The results showed that before filing SZ and AC samples presented equiaxial grains with the SZ sample having a much finer microstructure compared to AC. The values of grain sizes are around 150 μm and 1–2 μm for the AC and SZ samples, respectively. After filing, both samples presented similar grain sizes of only 60 nm. Although they attained similar grain sizes, the filings from SZ were more homogeneous and presented thinner innerlayers compared to its AC counterpart. The filings taken out from the SZ presented much faster kinetics for hydrogen absorption mainly due to its thinner innerlayers and its finer second-phase particle distribution, reaching up to 4.5 wt% of hydrogen uptake against only 1.0 wt% for AC sample after 10 h of absorption in the first cycle. Both samples presented similar behavior for full discharge time. These results show the possibility of using FSP with subsequent filing as a mean to obtain materials with suitable properties for use as energy carriers with enhanced kinetics and better oxidation resistance in shorter processing times.

In this work, we report on the friction stir weldability of a semi-solid cast ZK60 alloy modified with 1.5 wt% mischmetall in the lap-joint configuration using a 120WV4 steel tool with concave shoulder and conical pin. The coarser solidification microstructure in the semi-solid cast ZK60-1.5%RE alloy requires low strain rates and increased heat input to produce lap-joints without inner defects. This was achieved with 250 rpm tool rotation and 50 mm/min welding speed. Friction stir welding results in a very fine grained microstructure in the stir zone probably due to dynamic recrystallization. In the thermomechanically affected zones dynamic recrystallization seems to occur within the solute enriched intergranular zones. The distribution of longitudinal residual stresses exhibit stress maxima at both thermomechanically affected zones. A compression peak is observed at the retreating side, whereas a tensile stress maximum occurs at the advancing side.

The effect of a travel speed of 200 mm/min as well as a tool rotational speed of 1200 rpm on butt joint quality of friction stir welding (FSW) ZK60 magnesium casting alloy containing 1.5 wt.% rare earths (ZK60-1.5RE) was investigated to determine microstructure and residual stresses. FSW results in the generation of heterogeneous metallurgical structures consisting of the base material (BM), stirred zone (SZ) and thermo-mechanical affected zone (TMAZ). The stirring action also produced a non-uniform distribution and segregation of intermetalics. The transversal distribution of the longitudinal welding stresses exhibits a "M-like" shape with mostly tensile stresses under the shoulder region and only one compressive stress peak in the advancing side of the SZ and TMAZ. It could be demonstrated that FSW of ZK60-1.5RE alloy was successful in the welding conditions applied during the present work.

A crescente escassez de recursos energéticos renováveis bem como o aumento contínuo dos seus custos, tem requerido uma redução drástica no consumo de energia utilizada para o transporte de cargas e passageiros nas últimas décadas. Uma alternativa é a redução de peso com a utilização de ligas leves em substituição às ligas convencionais utilizadas no setor de transporte. Nesse conceito o uso de ligas de magnésio é justificado pela sua baixa densidade. Dentre as ligas de magnésio, a matriz ASTM série ZK é a que apresenta maior resistência mecânica e a adição de elementos de terras raras (RE) elevam a resistência à corrosão, a temperatura de trabalho e o limite de escoamento, devido à formação de filmes de óxidos finos e densos, além de intermetálicos de alto ponto de fusão e de maior dureza. A formação de intermetálicos do tipo MgZn de baixo ponto de fusão, torna as ligas de matriz do tipo ZK susceptíveis à formação de trinca à quente durante a soldagem, inviabilizando o uso de processos de soldagem convencionais. Uma alternativa é a solda por fricção e mistura mecânica (SFMM) realizada abaixo da temperatura de fusão. Neste trabalho, foram produzidas ligas ZK60, ZK60-1,5RE (liga ZK60 com adição de 1,5% em peso de mischmetal) por fundição convencional e ZK60-1,5RE tixofundidas com batimento mecânico no estado semissólido. Todas foram laminadas a quente em um laminador simétrico e soldadas por fricção e mistura mecânica. Os métodos de fundição e resfriamento apresentaram materiais isentos de defeitos e com homogeneidade química, além do batimento mecânico proporcionar uma microestrutura com grãos globulares homogêneos. A adição de Mischmetal deu origem a uma microestrutura com granulometria aproximadamente 22% menor. Quando comparado com o método de fundição, a liga fundida com batimento no estado semissólido apresentou uma diminuição no tamanho médio de grão de aproximadamente 26%. A laminação deu origem a uma microestrutura parcialmente recristalizada, com tamanho médio de grãos entre 3 e 4 μm. A rede de intermetálicos foi quebrada, porém, manteve-se contínua para as ligas com adição de Mm. Quanto à resistência mecânica, a liga ZK60 foi superior, devido à menor quantidade e redes intermitentes de intermetálicos, uma vez que tanto para as ligas fundidas quanto para as laminadas, as trincas foram originadas nas regiões de aglomeração de intermetálicos. As ligas com adição de Mm apresentaram melhor estabilidade térmica durante a soldagem e melhor acabamento superficial, sendo possível a soldagem com rotação de 1200 rpm e velocidade de avanço de 400 mm/min enquanto a liga ZK60 só foi possível a soldagem com 200 mm/min. As análises das tensões residuais apresentaram valores e perfis semelhantes e seguem o fluxo de material, bem como a textura dos cordões de solda. Os mapas de microdureza na secção transversal do cordão de solda revelaram maior dureza nas zonas de mistura, e valores ainda maiores e mais homogêneos para liga ZK60, pode-se afirmar que os intermetálicos do tipo MgZn tem maior dureza que os do tipo MgZnRE. The growing scarcity of renewable energy resources, as well as the continued rise in costs has required in recent decades a dramatic reduction in energy used for transportation freight and passenger, which is increasing daily all over the world. An alternative is to weight reduction with the use of light alloys, this concept the use of magnesium alloys is justified by their low density, about 1/3 lower than that of aluminum. Among the magnesium alloy, the matrix is ZK type that has greater mechanical strength and the addition of rare earth elements (RE) to increase corrosion resistance, working temperature and yield strength due to the formation of thin films and density oxides, and intermetallic of the high melting point and higher hardness. The formation of intermetallic of the MgZn type, which has a low melting point, makes alloys with matrix of the ZK type susceptible to formation of hot crack during the welding, making impossible the use of conventional welding processes, an alternative is the friction stir welding (FSW) that the union is made below the melting point. This work shows the studies the addition of 1.5% wt. of mischmetal (Mm) in the ZK60 alloy and effects of the casting process with mechanical mixing in the semi-solid state. Were produced the alloys: ZK60, ZK60-1.5RE with conventional casting and ZK60-1.5RE Tixo with mechanical mixing in the semi-solid state, all were hot-rolled in a symmetrical laminator and welded with friction stir welding (FSW) process. The methods of casting and cooling gave resulted in materials free of defects and chemical homogeneity, and the mechanical mixing provides homogeneous microstructure with globular grains. The alloy with mischmetal addition had an average grain size of about 22% lower than ZK60 alloy, when compared to the casting method the ZK60- 1.5RE Tixo alloy had an average grain size of about 26% lower than ZK60-1.5RE alloy. The rolling process gave rise to a partially recrystallized microstructure with average grain size of between 3.3 and 4.23 μm, the intermetallic network were broken, however, kept continuous for alloys with Mm addition. As for mechanical strength was higher for ZK60 alloy, due smaller amount and intermittent network of the intermetallic. The alloys with Mm addition had better thermal stability during welding and showed better surface quality, being possible to do a welding with rotation of 1200 rpm and advancing speed of 400 mm/min while the ZK60 alloy only was possible the welding with advancing speed of 200 mm/min. The analyzes of residual stresses had similar values and profiles and follow the flow of material as well as the texture of the weld beads. The micro hardness maps in the cross section of the weld bead showed a higher hardness in the mixing zones, and higher and more homogeneous values for ZK60 alloy, and can thus affirm that the intermetallic MgZn type has higher hardness than the MgZnRE type.

In this investigation the commercial ZK60 magnesium alloy modified with 2.5 wt.% of mischmetal was processed by melt spinning (MS) and equal-channel angular pressing (ECAP), both followed by extensive cold rolling (CR). The results indicate that MS was effective to produce small grain sizes in the order of 700 nm, while specimens prepared only by ECAP reached about 50 μm. However, melt spun ribbons showed long activation (first hydrogenation) times of more than 30 h in contrast to ECAP, which took about 10 h. In addition, after the activation process, the hydrogen storage capacity of ECAP was poorer than MS (2.5 and 3.3 wt.% of H2, respectively). Additional processing by CR caused further grain refinement and breakage of intermetallic particles, as well as favoring crystallographic texture in the (002) direction. All these features promoted a significant improvement in the hydrogen storage capacity, and in the absorption kinetics of the specimens processed by MS and ECAP.

Severe plastic deformation techniques have been extensively used to improve hydrogen storage properties of magnesium based alloys. In this work, the commercial magnesium alloy ZK60 (Mg-6Zn-1Zr in wt.%) was modified with addition of 2.5 wt.% of mischmetal (55Ce-24La-15Nd-4Pr in wt.%) and subsequently processed by equal-channel angular pressing (ECAP) and extensive cold rolling (CR). Due to the mischmetal addition, a network of intermetallic particles was formed at the grain boundaries. Besides Zn and Zr, the particles also contained the rare-earth elements La and Ce. With CR, a breakage of intermetallics occurred, that could also have played a role in enhancing the hydrogen storage properties. Ultimately, after the combined processing of ECAP followed by CR cold rolling, a significant increase in the storage capacity and activation kinetics was observed.

In this work, the casting process under mechanical agitation in the semi-solid state was investigated for the production of ZK60 magnesium alloy modified with the addition of 2.5% wt of mischmetal. The results show that this process enables the production of ingots with homogeneous chemical composition and free of shrinkage, inner defects and internal oxidation. The as-cast microstructure consists of an α-Mg matrix with globular grains reinforced by a grid of distinct intermetallics of Mg-Zn, Mg-Zn-RE and Mg-RE type along the grain boundaries. The yield strength at room temperature undergoes more than 50% increase during direct T5 aging, thus reaching 170 MPa. At 300°C, however, the dispersion of nanometric precipitates does not modify the hot deformation behavior of the aged alloy, which undergoes dynamic recrystallization in a similar manner to the as-cast alloy. DRX at 300°C is fastest for the alloy solution-treated at 500°C.