Ca Mn Research Articles

Significantly enhanced grain boundary Zn and Ca co-segregation of dilute Mg alloy via trace Sm addition

Increasing the level of grain boundary (GB) segregation is one of the effective strategies for the preparation of new high-performance Mg alloys. Here based on careful experimental design, we clearly demonstrate that the addition of trace Sm could significantly increase the GB segregation concentration of Zn and Ca in the as-extruded dilute Mg–Zn–Ca–Mn alloy, and confirm that the increased GB segregation could improve the yield strength of the as-extruded alloy and further inhibit the grain growth and the separation of the segregation atmosphere from GBs during annealing. The proposed idea of multi-element promoting efficient GB segregation is expected to contribute to the design strategy of advanced Mg alloys.

Geochemistry and Diagenetic Evidence of Middle-Late Permian Deposits, Northern Iran

This study provides a evaluation of the initial carbonate mineralogy, and diagenetic condition of the Ruteh Formation, a middle-late Permian carbonate sequence, in the Emarat section in Central Alborz, northern Iran. 200 samples were examined for petrographical contents and thirty-four samples were collected for geochemical analysis. The high Sr and Na contents, Sr/Na>1, and the presence of dolomites and dissolution fractures are indicative aragonite early mineralogy. The diagenetic process in the Ruteh Fm. are an indication of the marine, meteoric and burial diagenetic environments. The original carbonate texture in the Ruteh Fm. are Severely affected by diagenetic process. The data obtained from the values of the Major (Ca and Mg), minor (Sr, Na, Fe, and Mn), oxygen and carbone isotopes show the initial aragonite composition of the Ruteh Fm. deposited in a subtropical shallow water. An open diagenetic system was indicated by changes in the values of Sr / Ca and δ18O vs. Mn. The shallow burial diagenetic temperature of the Ruteh carbonate was approximate 28.6°C with the maximum diagenetic temperature of 53.4°C.

Investigations of High-Strength Mg-Al-Ca-Mn Alloys with a Broad Range of Ca+Al Contents.

The low mass and high specific stiffness of Mg alloys make them particularly interesting as means of transportation. Due to further desirable properties, such as good machinability and excellent castability, Mg alloys have gained acceptance as castings in high-volume applications, such as gearbox housings and automotive steering wheels. However, in forming processes, such as extrusion and forging, Mg alloys find little to no industrial use at the moment. The reasons for this are their poor formability, which is reflected in limited processing speeds and low ductility, and their modest mechanical performance, compared to competing materials, such as Al alloys and high-strength steels. Much research is being conducted worldwide on high-strength Mg alloys, most of which rely on high levels of rare earths, making these materials both ecologically and economically questionable. Here, it is shown that high yield strengths (>300 MPa) can be achieved in the Mg–Al–Ca system while maintaining good ductility, using only low-cost elements. The investigations have shown that these properties can be adjusted over broad alloy compositions, which greatly simplifies both the processing and recyclability.

Experimental investigation on the mechanical properties and strain rate sensitivity of Mg–Al–Ca–Mn alloy under various strain rates

An Mg-0.8Al-0.1Ca-0.4Mn (AXM080104, wt%) alloy was developed with extraordinary extrudability. The mechanical properties and strain rate sensitivity of the alloy were evaluated under various strain rates. The as-extruded alloy exhibited a tensile 0.2% proof stress of 222 MPa and an ultimate tensile strength of 380 MPa at the strain rate of 500/s. The performance of the extruded AXM080104 is superior to that of the AZ31 alloy at the high strain rate. The deformation mechanism of the extruded AXM080104 was examined and analyzed. The high strength is attributed to the simultaneous activation of multiple slip systems, and then a large number of dislocations are packed and entangled at the grain boundaries to cause work hardening.

Effect of Al on the Microstructure and Mechanical Properties of Mg–Sn–Ca–Mn Wrought Alloy

Effect of Al on the Microstructure and Mechanical Properties of Mg–Sn–Ca–Mn Wrought Alloy

Structure and Mechanical Properties of Al–Ca–Mn–Fe–Zr–Sc Eutectic Aluminum Alloy after Warm Equal Channel Angular Pressing

Structure and Mechanical Properties of Al–Ca–Mn–Fe–Zr–Sc Eutectic Aluminum Alloy after Warm Equal Channel Angular Pressing

Structure and mechanical properties of Al–Ca–Mn–Fe– Zr–Sc eutectic aluminum alloy after equal channel angular pressing

Multicomponent eutectic alloys developed in recent years based on the Al–Ca system have high practical application prospects due to their low density, high corrosion resistance, good processability when casting, and high formability in the as-annealed state. Alloy hardening is achieved by doping with Mn, Fe, Zr, Sc and other elements. Obtaining an ultrafine-grained state in aluminum alloys by the methods of severe plastic deformations, e.g. equal channel angular pressing (ECAP), significantly increases the complex of their mechanical properties. In this regard, the purpose this paper was aimed to study the effect of warm ECAP on the structure, mechanical properties and thermal stability of the eutectic aluminum alloy, wt.%: Al–3.5Ca–0.9Mn–0.5Fe–0.1Zr–0.1Sc. The ECAP process was carried out on as-cast alloy specimens with a diameter of 20 mm (temperature 400 °C, route BC, channel intersection angle 110°, number of passes N = 6). It is shown that as a result of ECAP, a developed substructure with high-density dislocations and released nanosized Al6(Mn, Fe), and Al3Sc particles is formed in the alloy, as well as primary coarse Al6(Mn, Fe) particles and eutectic Al4Ca particles are reduced in size. Such a change in the structure during ECAP leads to the significant hardening of the alloy: its strength properties increased by 1.5–2.0 times, and relative elongation decreased by 1.3 times in the longitudinal section sample and slightly changed in the «transverse» section sample as compared to the initial condition.

Corrosion Behavior of Mg–Zn–Ca–Mn Alloy Coated with Nano-hydroxyapatite by Cyclic Voltammetry Method

Coating and alloying are the two possible solutions for enhancing the corrosion resistance of magnesium. Nanostructured hydroxyapatite (n-HA) was coated on Mg–1% Zn–0.5% Ca–0.2% Mn by cyclic voltammetry method to increase its biocompatibility and bioactivity alongside corrosion resistance. XRD and EDS analyses approved the formation of hydroxyapatite. A central composite design (CCD) coupled with response surface methodology (RSM) was employed to optimize the four selected variables. Corrosion current density obtained from polarization tests in the simulated body fluid (SBF) was considered as the main response for optimization. The experimental values were fitted well by the derived model (R2 = 96.8%). The proposed optimum condition was − 1.4 V, 75 °C, 7 cycles, and 0.05 M for the start potential, temperature, cycle number and concentration of NaNO3, respectively. The corrosion current density of the sample made at the optimum condition was decreased around 90% compared with the bare one (1423 µA/cm2 to 136 µA/cm2). The FESEM images confirmed the formation of n-HA coating on magnesium alloy. The best coating adhesion among all samples was determined to be 4.52 MPa. Finally, the EIS test confirmed the results of previous corrosion experiments. The corrosion resistance of the optimized sample was measured to be about 2000 Ω cm2.

Microstructure refinement, mechanical and biocorrosion properties of Mg–Zn–Ca–Mn alloy improved by a new severe plastic deformation process

In this study, the microstructural evolution, mechanical properties and biocorrosion performance of a Mg–Zn–Ca–Mn alloy were investigated under different conditions of heat treatment, extrusion, one pass and two passes of half equal channel angular pressing (HECAP) process. The results showed significant grain refinement of the homogenized alloy after two passes of HECAP process from 345 µm to 2 µm. Field emission scanning electron microscopy (FESEM) revealed the presence of finer Mg 6 Zn 3 Ca 2 phase as well as α-Mn phase after HECAP process. The results also showed that mechanical characteristics such as yield strength, ultimate tensile strength and elongation of the HECAPed samples improved by ∼208%, ∼144% and ∼100% compared to the homogenized one, respectively. Crystallographic texture analysis indicated that most of the grains at the surface were reoriented parallel to the (0001) basal plane after HECAP process. Electrochemical corrosion tests and immersion results indicated that the sample with two passes of HEACP had the highest biocorrosion resistance confirming that the basal planes had the lowest corrosion rate compared to the non-basal ones. The mechanical behavior and bio-corrosion evaluation demonstrated that the HECAPed Mg–Zn–Ca–Mn alloy has great potential for biomedical applications and a mechanism was proposed to explain the interrelations between the thermomechanical processing and bio-corrosion behavior.

Analysis and evaluation of mineral elements of Chrysanthemum morifolium for medicinal and tea use of different germplasm resources

In this study, 23 germplasm resources of Chrysanthemum morifolium used in medicine and tea were collected from Dabie Mountains and its surrounding producing areas, and the contents of 13 mineral elements were determined and compared. The thermal maps of correlation analysis, principal component analysis and cluster analysis were used for comprehensive evaluation. The results showed that the average content of each element in Ch. morifolium of different germplasm resources was: K>N>P>Mg>Ca>Fe>Mn>Zn>Cu>Ni>Cr>Pb>Cd, and the leaves were: K>N>Ca>Mg>P>Fe>Mn>Zn>Cr>Cu>Ni>Pb>Cd. There are rich contents of N, P, K, Ca, Mg and Fe in Ch. morifolium flowers and their leaves, among them, K element has the largest change range, while N, Ca, Fe, Mg and Zn elements have a larger change range. The absorption and accumulation of each element in the leaves of different germplasm resources varied greatly. The correlation analysis shows that there is a strong positive correlation between Ca element, Mg, Mn and Cd element.Principal component analysis in Ch. morifolium flowers characteristic elements for Mn, Cr, Cu, P, K, can be used as a Ch. morifolium resources to identify the characteristics of the elements, choose top five principal component(F1-F5) comprehensive evalua-tion of medicinal Ch. morifolium, scored in the top five varieties for Hangiu-Fuhuangju, Hangju-Xiaoyangju, Hangju-Sheyangju, Hangju-Dayanghua, Hangju-Subeiju,indicates that in terms of mineral elements, the five medicinal Ch. morifolium resources quality is better. The PCA score chart can divide 23 Ch. morifolium resources into 4 groups, and the cluster analysis heat map divides 23 Ch. morifolium resources into 5 groups. All the Ch. morifolium resources of the same type can be well clustered together, indicating that the difference in mineral element content of Ch. morifolium germplasm resources is closely related to genetic factors.

Effect of Warm Equal-Channel Angular Pressing on the Structure and Mechanical Properties of Al–Mg–Ca–Mn–Fe–Zr Alloy

The effect of equal-channel angular pressing on the structure, mechanical properties, and thermal stability of the Al–5% Mg–1% Ca–0.9% Mn–0.5% Fe–0.1% Zr alloy has been studied. Samples in the annealed state have been subjected to ECAP under the following conditions: by route BC, at a temperature of 400°C, an angle of channel intersection of 110°, and the number of passes of N = 8. ECAP results in (i) the formation of a substructure with a high dislocation density and (ii) the precipitation of Al6(Mn, Fe) and Al3Zr nanoparticles in the alloy. ECAP increases both strength and plasticity of the alloy. The strength of the alloy after ECAP increases by a factor of 1.3–1.5 and the relative elongation, by a factor of 2.0–2.5 in comparison with the initial state.

Calcination Behaviour of Nsuta Rhodochrosite Ore in the Presence and Absence of End-of-Life High Density Polyethylene

This research investigated the calcination behaviour of the Nsuta Rhodochrosite (MnCO3) in the presence and absence of end-of-life high density polyethylene (HDPE) using a custom-made palm kernel shell fired furnace. Samples of pulverised Nsuta rhodochrosite were heated rapidly for 30, 40, 50 and 60 minutes, coupled with temperature measurements to determine the maximum temperature attained in the fireclay crucible. The procedure at 60 min was repeated using three blends of rhodochrosite samples containing different masses of HDPE (30 g, 40 g and 50 g) and heated for an hour. For gas analyses studies during calcination, cylindrical compacts of rhodochrosite ore in a LECOTM crucible were heated rapidly with and without high density polyethylene (HDPE at C/O ratio = 1.0, 1.5, and 2.0) in a horizontal tube furnace for 600 s at 1150 °C under high purity argon gas and the off gas was continuously analysed for CH4, CO and CO2 using an online infrared gas analyser. The content of H2 in the off gas was detected using a GC3 gas chromatographic analyser equipped with a thermal conductivity detector. The Nsuta rhodochrosite ore was found to consist of a mixture of manganese II carbonate (MnCO3), silica (SiO2), mixed transition metal carbonate of the form Ca(Mn, Mg)(CO3)2 and mixed metal silicate of the form Ca0.6Mg1.94Si2O6. Calcination results indicated visible colour changes (from grey to dark brown), along with significant changes in the mass before and after calcination. In the absence and presence of the polymer, measured temperatures in the crucible ranged from 1001 °C to 1366 °C and 1361 °C to 1369 °C, respectively. Analyses by XRF showed marginal increase in the content of Mn in the calcined ore with HDPE addition. Gas analyses indicate that blending the carbonate with HDPE before heating results in significant decrease in the amount of CO2 emitted.
 
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Improving room-temperature stretch formability of a high-alloyed Mg–Al–Ca–Mn alloy sheet by a high-temperature solution-treatment

Various solution-treatments were applied on a rapidly solidified and subsequently rolled Mg-7.50Al-1.07Ca-0.17Mn (mass%) alloy sheet, and a room-temperature stretch formability, tensile properties, microstructures, and textures of the solution-treated sheets have been investigated. Although the solution-treatment at 400 °C gives high strengths, the sheet shows poor room-temperature stretch formability with the Index Erichsen value of 4.8 mm due to densely dispersed second phase particles. Also, the particles tend to distribute to the rolling direction, leading to limited elongation to failure of 11.0% along the transverse direction. The solution-treatment at higher temperature leads to the sparse and relatively uniform dispersion of the particles. This results in the significant improvement in the room-temperature stretch formability and ductility. The Index Erichsen increases to 6.8 mm by the solution-treatment at 450 °C for 4 h, and the sheet shows large elongation to failure of 19.1% and 17.1% along the rolling and transverse directions, respectively. The sheet also exhibits high strengths and in-plane isotropic properties, tensile strength over 320 MPa and 0.2% proof stress of ~180 MPa could be obtained due to fine grain structure with the average grain size of 9.5 μm.

Development of a high-strength Mg alloy with superior ductility through a unique texture modification from equal channel angular pressing

Abstract In the current study, a homogenous ultra-fine grained microstructure with average grain size of 1.0 µm is achieved in the Mg–Zn–Ca–Mn alloy through the reduplicative equal channel angular pressing (ECAP) at 300 °C, and the mechanical properties are remarkably improved, with room-temperature yield strength of 269.6 MPa and elongation of 22.7%. The twinning deformation results in a discontinuous recrystallization behavior in the initial stage of ECAP. With further deformation, the continuously dynamic recrystallization contributes to an obvious grain refinement effect. The activation of non-basal slip system leads to the formation of a unique basal texture, which is related to the elevated ECAP temperature and the decreased grain size. Both grain refinement and texture modification derived from ECAP process result in the increase of yield strength, while the cracked secondary phase particles are beneficial to the enhanced ductility, through reducing the stress concentration and hindering premature failure.

Evolution of microstructure, phases and mechanical properties in lean as-cast Mg–Al–Ca–Mn alloys under the influence of a wide range of Ca/Al ratio

In the present investigation, the microstructure and phase evolution, and their implications on the mechanical properties for different Ca/Al ratios (within ~0.06–2.21, wt.%) in lean as-cast Mg–Al–Ca–Mn alloys are experimentally studied. Further, the evolution of the second phases and the matrix phase in different alloy compositions have been estimated through thermodynamic calculations using Scheil conditions. The primary phase in all these alloys is a solid solution of hcp Mg with the other elements like Al and Ca. Apart from the fine Al8Mn5 particles present in all the compositions, the major eutectic second phase is γ-Mg17Al12 in the specimen with Ca/Al ratio ~0.06, C36-(Mg,Al)2Ca in the specimen with Ca/Al ratio ~0.28 and C14–Mg2Ca in the specimens with Ca/Al ratio ~1.56 and ~2.21. The area fraction of the eutectic second phases increases from ~2.1 to ~7.2% with the Ca/Al ratio, with a concomitant increase in its network connectivity as confirmed through fractal analysis. Contrarily, the lattice parameters (both a and c) and the elastic modulus (E) of the matrix phase decrease with increasing Ca/Al ratio, due to the decreasing concentration of solute atoms in the matrix. Therefore, the specimen with the minimum Ca/Al ratio (~0.06) attains maximum strength (YS ~130 MPa, UTS ~183 MPa), primarily owing to solid solution strengthening from higher solute content and precipitation strengthening from fine γ-Mg17Al12 particles. The large fraction and strong networks of hard and brittle Mg2Ca phase promote cracks during tensile deformation and deteriorates the ductility (≤1.6%) and work hardening response in the alloys with higher Ca/Al ratios (≥1.56).

Improved tensile properties of low-temperature and low-speed extruded Mg–χAl–(4.8 − χ)Ca–0.6Mn alloys

In this work, the microstructure and mechanical properties of Mg–Al–Ca–Mn alloys with different Ca/Al ratios (0.2, 0.6 and 1.0) have been investigated. The results showed that with the increase of the Ca/Al ratios, the grain sizes of the alloys were significantly refined, and the morphologies and types of main second phases changed from a block Mg17Al12 phase to a semi-continuous Al2Ca (C15) phase and a continuous network (Mg, Al)2Ca (C36) phase. The extruded Mg–2.4Al–2.4Ca–0.6Mn alloy, which was consisted of dynamically recrystallized grains and undynamically recrystallized regions, possessed outstanding mechanical properties with the yield strength of 335.9MPa, the ultimate tensile strength of 354.7MPa and the elongation of 8.4%. This was mainly due to the resultant effects of grain refinement strengthening, secondary phases strengthening, texture strengthening and work hardening.

Role of Zn on the room temperature formability and strength in Mg–Al–Ca–Mn sheet alloys

We clarified the role of Zn on the mechanical properties and texture evolution in Mg-1.2Al-0.5Ca-0.4Mn-xZn (wt.%, x = 0, 0.8 and 1.6) alloy sheets fabricated by twin-roll casting and hot rolling. The room temperature stretch formability of the solution-treated sheet is improved with increasing Zn content, x. The Mg-1.2Al-0.5Ca-0.4Mn-1.6Zn alloy shows excellent stretch formability with the largest Index Erichsen value of 8.2 mm due to a weak transverse direction split texture. The development of the transverse direction split texture is attributed to the preferential nucleation of recrystallized grains at double twin boundaries promoted by the moderate segregation of Zn and Al. Subsequent artificial aging at 170 °C for 2 h (T6) leads to a substantial increase in strength without loss of ductility. The peak-aged Mg-1.2Al-0.5Ca-0.4Mn-1.6Zn alloy exhibits a high tensile yield stress of 210 MPa with an excellent elongation of 30.1% because of the dense dispersion of Guinier Preston zones within the Mg matrix. The insights gained in this work would establish a base for rational design and fabrication of bake-hardenable magnesium alloy sheet with excellent room temperature formability and high strength.

Effect of extrusion temperature on microstructure and mechanical properties of a low-alloying and ultra-high strength Mg–Zn–Ca–Mn matrix composite containing trace TiC nanoparticles

Abstract Mechanical properties of microalloying Mg–2.2Zn–1.8Ca–0.5Mn (wt%) matrix composites reinforced by 0.5 wt% TiC nanoparticles before and after extrusion were investigated based on the detailed microstructural analysis. A uniform distribution of TiC nanoparticles was realized in the nanocomposite by the method of ultrasonic-assisted semisolid stirring. The morphology of eutectic Ca2Mg6Zn3 phases changed from plate-like in the free TiC nanoparticles region to lamellar in the dense TiC nanoparticles region for the as-cast nanocomposite. Both the grain structure and precipitates were obviously refined as the extrusion temperature decreased from 350 to 270 °C. The nanocomposite exhibited excellent tensile yield strength (352–428 MPa) which was governed by the extrusion temperature. The grain refinement strengthening with the contribution ratio of ∼80% to this strength increment was much higher relative to thermal expansion effect, Orowan strengthening and dislocation strengthening. Ultrafine recrystallized grain structure with a substantial of fine precipitates appeared in the nanocomposite extruded at 270 °C. The refined grain structure was not only due to dynamic recrystallization, but also the synergistic pinning effect of nano-TiCp, precipitated MgZn2 and α-Mn particles. The tensile toughness value of nanocomposite after extrusion improved with increasing the extrusion temperature. Massive micro-cracks formed along the remnant coarse Ca2Mg6Zn3 led to the structural failure during tension.

Kimberlite Metasomatism of the Lithosphere and the Evolution of Olivine in Carbonate-rich Melts — Evidence from the Kimberley Kimberlites (South Africa)

AbstractOlivine is the most abundant phase in kimberlites and is stable throughout most of the crystallization sequence, thus providing an extensive record of kimberlite petrogenesis. To better constrain the composition, evolution, and source of kimberlites we present a detailed petrographic and geochemical study of olivine from multiple dyke, sill, and root zone kimberlites in the Kimberley cluster (South Africa). Olivine grains in these kimberlites are zoned, with a central core, a rim overgrowth, and occasionally an external rind. Additional ‘internal’ and ‘transitional’ zones may occur between the core and rim, and some samples of root zone kimberlites contain a late generation of high-Mg olivine in cross-cutting veins. Olivine records widespread pre-ascent (proto-)kimberlite metasomatism in the mantle including the following features: (1) relatively Fe-rich (Mg# <89) olivine cores interpreted to derive from the disaggregation of kimberlite-related megacrysts (20 % of cores); (2) Mg–Ca-rich olivine cores (Mg# >89; >0·05 wt% CaO) suggested to be sourced from neoblasts in sheared peridotites (25 % of cores); (3) transitional zones between cores and rims probably formed by partial re-equilibration of xenocrysts (now cores) with a previous pulse of kimberlite melt (i.e. compositionally heterogeneous xenocrysts); (4) olivine from the Wesselton water tunnel sills, internal zones (I), and low-Mg# rims, which crystallized from a kimberlite melt that underwent olivine fractionation and stalled within the shallow lithospheric mantle. Magmatic crystallization begins with internal olivine zones (II), which are common but not ubiquitous in the Kimberley olivine. These zones are euhedral, contain rare inclusions of chromite, and have a higher Mg# (90·0 ± 0·5), NiO, and Cr2O3 contents, but are depleted in CaO compared with the rims. Internal olivine zones (II) are interpreted to crystallize from a primitive kimberlite melt during its ascent and transport of olivine toward the surface. Their compositions suggest assimilation of peridotitic material (particularly orthopyroxene) and potentially sulfides prior to or during crystallization. Comparison of internal zones (II) with liquidus olivine from other mantle-derived carbonate-bearing magmas (i.e. orangeites, ultramafic lamprophyres, melilitites) shows that low (100×) Mn/Fe (∼1·2), very low Ca/Fe (∼0·6), and moderate Ni/Mg ratios (∼1·1) appear to be the hallmarks of olivine in melts derived from carbonate-bearing garnet-peridotite sources. Olivine rims display features indicative of magmatic crystallization, which are typical of olivine rims in kimberlites worldwide; that is, primary inclusions of chromite, Mg-ilmenite and rutile, homogeneous Mg# (88·8 ± 0·3), decreasing Ni and Cr, and increasing Ca and Mn. Rinds and high-Mg olivine are characterized by extreme Mg–Ca–Mn enrichment and Ni depletion, and textural relationships indicate that these zones represent replacement of pre-existing olivine, with some new crystallization of rinds. These zones probably precipitated from evolved, oxidized, and relatively low-temperature kimberlite fluids after crustal emplacement. In summary, this study demonstrates the utility of combined petrography and olivine geochemistry to trace the evolution of kimberlite magmatic systems from early metasomatism of the lithospheric mantle by (proto-)kimberlite melts, to crystallization at different depths en route to surface, and finally late-stage deuteric or hydrothermal fluid alteration after crustal emplacement.

Microstructure, Tensile Properties and Work Hardening Behavior of an Extruded Mg–Zn–Ca–Mn Magnesium Alloy

A new Mg-2.2 wt% Zn alloy containing 1.8 wt% Ca and 0.5 wt% Mn has been developed and subjected to extrusion under different extrusion parameters. The finest (~ 0.48 μm) recrystallized grain structures, containing both nano-sized MgZn2 precipitates and α-Mn nanoparticles, were obtained in the alloy extruded at 270 °C/0.01 mm s−1. In this alloy, the deformed coarse-grain region possessed a much stronger texture intensity (~ 32.49 mud) relative to the recrystallized fine-grain region (~ 13.99 mud). A positive work hardening rate in the third stage of work hardening curve was also evident in the alloy extruded at 270 °C, which was related to the sharp basal texture and which provided insufficient active slip systems. The high work hardening rate in the fourth stage contributed to the high ductility extruded at 270 °C/1 mm s−1. This alloy exhibited a weak texture, and the examination of fracture surface revealed highly dimpled surfaces. The optimum tensile strength was achieved in the alloy extruded at 270 °C/0.01 mm s−1, and the yield strength, ultimate tensile strength and elongation to failure were ~ 364.1 MPa, ~ 394.5 MPa and ~ 7.2%, respectively. Fine grain strengthening from the recrystallized fine-grain region played the greatest role in the strength increment of this alloy compared with Orowan strengthening and dislocation strengthening in the deformed coarse-grain regions.