Shear Punch Test Research Articles

Microstructural features and mechanical behavior of duplex stainless steel/low carbon steel friction stir dissimilar weld

This paper aims to understand the effect of friction stir butt welding on the microstructure and mechanical performance, measured in terms of hardness characteristics, transverse tensile test, and shear punch, of dissimilar weld of duplex stainless steel (DSS) and low carbon steel (LCS). The dynamic recrystallization, material intermixing, and atomic interdiffusion between DSS and LCS governed the microstructure of the stirred zone. The stirred zone was free from harmful intermetallic phases like the sigma phase. It was identified that three distinct metallurgical regions feature the stirred zone, including (i) dual-phase zone (DPZ) with an unbalanced fine duplex microstructure of austenite and ferrite, (ii) ferrite phase zone (FPZ) with fine-grained ferrite strengthened by an enhanced Ni and Cr content, (iii) martensite zone (MRZ), which was formed due to the formation of thermally unstable austenite at high temperatures due to Cr, Ni, and C interdiffusion between DPZ and FPZ. Furthermore, when LCS was positioned on the advancing side, a higher fraction of martensite was formed in the stirred zone due to the more efficient material mixing. The shear punch test indicated that the shear strength of the stirred zone in the dissimilar welds was ∼130% and ∼16% higher than that in the LCS and DSS base metals, respectively. The contributions of solid solution hardening and grain boundary hardening to the hardness/strength of the stirred zone were elucidated.

Phase Stability, Microstructure, and Mechanical Properties of Spark Plasma Sintered Nanocrystalline Boron-Doped AlCoFeMnNi High-Entropy Alloy

The microstructure and mechanical properties of mechanically alloyed and spark plasma sintered AlCoFeMnNi-xB (x = 0, 0.5, 1, and 5 at. %) high-entropy alloys (HEAs) have been investigated. Boron-doped HEAs were synthesized using mechanical alloying up to 50 h of milling. Synthesized powders were then consolidated at 850, 900, and 950 °C for 10 min under a uniaxial pressure of 40 MPa using spark plasma sintering (SPS). A scanning electron microscope, which was equipped with energy dispersive spectroscopy (EDS), together with an optical microscope (OM) were used to analyze the microstructural evolution. X-ray diffraction analysis was used to differentiate the phases formed in the solution. The mechanical properties of the sintered specimens were analyzed using the shear-punch test (SPT). The fracture surface of the SPT samples was studied using SEM. Thermodynamic calculations revealed that by employing this process, it is possible to produce solid solution HEAs with a duplex FCC + BCC structure. It was shown that boron-doped AlCoFeMnNi high-entropy alloys contain some unique attributes. SPS at 900 °C for a sample with boron up to 0.5 at. % leads to the formation of an alloy with the highest shear strength. A further increase in the boron content in the boron-doped HEAs exhibited a decrease in the maximum shear strength. Finally, the correlations between the microstructural and mechanical characteristics of the sintered boron-containing high-entropy alloys are discussed.

Complementary research on the Al–Cu nanostructured composite processed by ARB: finite element, crystal plasticity, intermetallic, and failure analysis

A unique Al–Cu composite was manufactured using the accumulative roll bonding (ARB) process. For characterization purposes, a variety of methods was conducted on the resulting composite. Also, the shear band formation which is a prevalent phenomenon in the ARBed materials was analyzed using the finite element method (FEM). For experimental analysis, the crystallographic texture was evaluated for the material by the X-ray diffraction method (XRD). A well-developed rolling (β-fiber) texture was dominated on the Al side, however, recrystallization led to the occurrence of other component mainly around <001> orientation on the Cu side. Upon annealing, the formation of different intermetallic compounds (IMCs) was observed and evaluated using scanning electron microscopy (SEM). An unexpected AlCu4 was detected between the layers as the prominent IMC after the annealing process. Furthermore, the shear punch test was employed for the material's mechanical characterization. It was observed that the strength of the composite material was higher than that of primary metals i.e., Al and Cu. Finally, failure analysis revealed a ductile fracture with separated layers at earlier cycles and a brittle fracture at higher ARB cycles.

Superplasticity in a coarse-grained as-cast magnesium alloy

Superplasticity of a coarse-grained cast Mg–2.5Gd–0.5Zr alloy was investigated by assessing the strain rate sensitivity index (m-value) through the shear punch testing (SPT) method in the temperature range of 623–748 K and shear strain rate range of 2.8 × 10−3–2.2 × 10−2 s−1. The initial as-cast grain size of about 150 μm was reduced to about 3.5 μm at the end of the test. This severe grain refinement caused by dynamic recrystallization (DRX) facilitated superplasticity in the studied cast alloy. According to the respective m-values of 0.51 and 0.53 obtained at 698 and 723 K, and the activation energy of 80 kJ mol−1, the prevailing mechanism of deformation was suggested as grain boundary sliding (GBS) controlled by grain boundary diffusion.

Study on fusion boundary microstructure and mechanical properties of austenitic stainless steel-nickel based dissimilar alloy materials welded joints

The metallographic test, microhardness test, and shear punch test of overlayer joint were carried out. The microstructure distribution and micro-zone mechanical properties of overlayer-girth weld fusion boundary (O-G), overlayer-austenitic (O-A) fusion boundary, and austenitic-grith weld fusion boundary (A-G) were studied respectively. At the same time, the type II boundary, DDC, and liquefaction crack were discovered. The results show that the microstructures on both sides of the O-G fusion boundary are γ phase and austenite-ferrite, respectively. There are three types of fusion limitations: type II boundary, direct fusion boundary, and transition fusion boundary. There are DDCs in the transition fusion boundary of the O-G zone, and liquefaction cracks caused by composition segregation in the inner of overlayer. The microstructures on both sides of the O-A fusion boundary are γ phase and uniaxial austenite, respectively, and there is no evident transition zone. Microstructures on both sides of the A-G fusion boundary are equiaxed austenite and austenite-ferrite (lath-skeleton-short rod). The average microhardness and shear strength of the O-A-G fusion border overlayer is the highest, 241 HV and 782 MPa respectively, and the microhardness decreases to 215 HV at DDCs defect. The microhardness and shear strength of base metal are 212 HV, 661 MPa, respectively. The microhardness and shear strength of the girth weld are 192 HV, 600 MPa, respectively. The maximum shear work of O zone is 1.62 J, and the minimum O-G fusion boundary is 1.12 J.

Hot deformation constitutive analysis and processing maps of the as-cast and wrought Mg–2.5Gd–0.5Zr alloy

Hot deformation behavior and constitutive analysis of the as-cast and extruded Mg–2.5Gd–0.5Zr alloy were compared, using the shear punch testing (SPT) method in the temperature range of 623–723 K and shear strain rate range of 2.8 × 10–3–2.2 × 10–2 s–1. The respective hyperbolic-sine exponents of 2.67 and 2.59 as well as activation energies of 183 and 275 kJ mol–1 obtained for the as-cast and extruded alloy suggested grain boundary sliding as the prevailing deformation mechanism. Surprisingly, regardless of the instability domains, the efficiency of power dissipation exceeded 30% in most areas in the processing maps of both cast and wrought conditions. The safe and instability domains were rather similar in both processing maps. The relatively high potential of the as-cast alloy for hot deformation, despite its initial coarse grain size of about 150 µm, can be ascribed to the severe dynamic recrystallization (DRX) during hot deformation caused by Zr. This could be economically advantageous, as there would be no need for homogenization of the as-cast material before deformation processing. The most noticeable optimum window occurred in the temperature range of 673–723 K for both as-cast and extruded conditions with a vaster strain-rate range for the extruded one (5.6 × 10–3–1.4 × 10–2 s–1), owing to its initial finer grain size. The instability domains, however, took place for both conditions in the temperature range of 648–673 K and strain rates of about 5.6 × 10–3 s–1, manifested by cracking in the deformed zone, and also at temperatures higher than 673 K and medium to high strain rates.

Thermal stability, grain growth kinetics, mechanical properties, and bio-corrosion resistance of pure Mg, ZK30, and ZEK300 alloys: A comparative study

Thermal stability, grain growth kinetics, tensile properties, and corrosion resistance of commercially pure (CP) magnesium can be tailored by zinc addition in conjunction with small additions of zirconium and rare earth (RE) elements, which need to be systematically investigated. Accordingly, the thermal stability, grain growth kinetics, tensile properties, and bio-corrosion resistance of hot rolled CP Mg, and ZK30 (Mg-3Zn-0.5Zr) and ZEK300 (Mg-3Zn-0.5RE-0.5Zr) alloys were compared in this work. The solute drag effect of Zn in the ZK30 alloy and the Zener pinning effect of CeZn 5 compound in the ZEK300 alloy were responsible for the improved thermal stability and higher grain growth activation energy of these alloys compared to CP Mg. The tensile properties of hot rolled ZK30 and ZEK300 alloys were superior due to their fine grain sizes. Moreover, corrosion tests in simulated body fluid (SBF) solution confirmed the higher corrosion resistance of the ZEK300 alloy for biomedical implant applications. The shear punch testing (SPT) results revealed that the ZEK300 alloy can better retain its superior mechanical properties during deformation/testing at elevated temperatures. Grain growth annealing led to a decrement in strength but an increment in the total elongations, and hence, the highest tensile toughness was obtained for the ZEK300 alloy with an average grain size of ~ 8.5 μm. Accordingly, this work proposed that RE addition at the micro-alloying level to a lean Mg-Zn alloy is quite effective in the enhancement of thermal stability, room/elevated-temperature mechanical properties, and bio-corrosion resistance.

Microstructure and hot shear deformation behavior of a fine-grained AA5083 aluminum alloy

Dual Equal Channel Lateral Extrusion (DECLE) was performed in different passes on an annealed AA5083 aluminum alloy. The microstructural evolution of the alloy was investigated using electron backscatter diffraction images and the dislocation density was determined by X-ray line profile analysis. It was found that DECLE is effective in grain refinement, and while dislocation density is almost saturated after the fourth pass of DECLE, applying the sixth pass results in more grain size reduction of annealed sample from 59.2 μm to 3.8 μm. To assess the mechanical behavior of the DECLE-processed materials, shear punch tests (SPT) at high temperatures (300–400 °C) and various strain rates (3×10−3−3×10−1s−1) were conducted. The shear stress-normalized displacement curves obtained from SPT were utilized to obtain the material constants such as the stress exponent (n) and the activation energy (Q) in the hyperbolic-sine constitutive model. The variations of n and Q were analyzed based on the microstructural features such as grain size, HAGBs fraction, dislocation density, and second phase particles fraction. The results suggest that the Q value is competitively influenced by these parameters. Accordingly, finer grain size, higher HAGBs volume fraction, lower second phase volume fraction, and smaller dislocation density result in lower Q values.

Improved mechanical properties of the cast Mg–2.5Gd–0.5Zr alloy via hot extrusion

Microstructural evolution and mechanical properties of the Mg–2.5Gd–0.5Zr alloy in the as-cast and extruded conditions were studied. Their flow behavior was investigated at room and elevated temperatures of 100, 175 and 250 °C through the shear punch testing (SPT) method. The as-cast alloy exhibited a non-dendritic microstructure due to the presence of Zr, which provided nucleation sites during solidification. A recrystallized microstructure was developed in the extruded alloy, due to the counteraction of Zr against the retarding effect of Gd on DRX. The enhancement in the strength of the extruded alloy was mainly ascribed to grain boundary strengthening. The reduction of shear yield stress (SYS) and ultimate shear strength (USS) with increasing the testing temperature in both as-cast and extruded conditions was a direct result of dislocation annihilation and reduction in the CRSS of non-basal slip systems. Both conditions developed reasonable ductility that was slightly enhanced with increasing temperature. The as-cast alloy, however, showed higher ductility and a more ductile fracture behavior compared to the extruded one at each testing temperature, caused by the synergy of twinning and slip in this condition and the very fine-grained structure of the extruded condition.

Effects of heat treatment and Y addition on the microstructure and mechanical properties of as-cast Mg–Si alloys

In Mg–Si alloys, both primary and eutectic Mg2Si particles normally appear with sharp edges, which can lead to weak mechanical properties as the result of stress concentration at the sharp corners of these brittle particles. Thus, it would be of great importance to modify the morphology of these particles. In this study, microstructure modification mechanisms after 0.5 wt% Y addition and heat treatment (HT) at 420 °C for 24 h are comprehensively studied in hypo-eutectic Mg–1Si and hyper-eutectic Mg–2Si alloys. Microstructural observations were performed using optical and scanning electron microscopy equipped with electron disperse spectroscopy, while phase analysis was done by X-ray diffraction. Mechanical properties of the studied alloys were evaluated by shear punch testing technique. The obtained results indicate that 0.5% Y addition to the as-cast Mg–1Si and Mg–2Si alloys could modify morphology of the eutectic Mg2Si from coarse lamellar to very short rod-shaped. The poisoning effect of Y was the main mechanism for this modification. The ultimate shear strength (USS) increased after Y addition to the Mg–1Si and Mg–2Si alloys, due to the modified eutectic Mg2Si morphology and also formation of fine Y-containing particles. Moreover, it was observed that HT could modify the morphology of the eutectic Mg2Si phase to the punctiform or disconnected rod-shaped in the studied alloys. Another important effect of HT was observed to be rounding sharp corners of the primary Mg2Si particles and changing their morphology to some new shapes such as star-like, indicating unstable morphology of the primary Mg2Si particles in the Mg–2Si–0.5Y alloy at high temperature. The USS values were improved for the Mg–1Si and Mg–2Si alloys after HT due to the modified morphology of the Mg2Si particles.

Probe-less friction stir spot processing (PFSSP) of AA5754/AA5083 joint by adding the B4C ceramics: Effect of shoulder features on mechanical properties and tribological behavior

This study aims to improve the local shear behaviors of dissimilar spot welds of Al alloys through a particle-dispersion strengthening mechanism. Probe-less friction stir spot processing of the AA5083-H112 and AA5754-O alloys with B4C ceramic reinforcement was investigated by modifying the tool shoulder surfaces. The smooth and scrolled shoulder tools were utilized for this study. The mechanical properties of the B4C-reinforced spots were examined via the use of the miniaturized shear punch testing method and the tensile-shear test. At an unchanged process condition, the scrolled shoulder tool improved particle dispersion and dislocation density to an extent while it significantly reduced the average B4C particle size from 60 to 6.71 μm more than that of the smooth shoulder tool. The scroll-pattern-assisted straining, material flow. The wear rate was significantly reduced in the sample fabricated with the scroll tool. The scrolled shoulder tool is recommended for the fabrication of the B4C-reinforced spots.

Effects of titanium addition on the microstructure and mechanical properties of quaternary CoCrFeNi high entropy alloy

The effects of minor Ti addition on the microstructure and mechanical properties of the as-cast quaternary equiatomic CoCrFeNi high entropy alloy were studied experimentally and supported by thermodynamic modeling. The phase evolution, microstructure, and shear properties were investigated using X-ray diffraction, optical and scanning electron microscopy, and the shear punch test. It was shown that during the solidification process, the interdendritic segregation of Ti resulted in discontinuous precipitation of the R-phase and serrated grain boundaries. The mechanism of grain refinement was attributed to some additional constitutional undercooling and intersection of tortuous grain boundaries; this, in turn, led to the formation of a bimodal grain structure. The shear elongation and shear strength of 1 and 2 at.% Ti-containing samples simultaneously increased, in comparison with the base alloy. This interesting improvement of the mechanical properties was related to the simultaneous grain refinement, precipitation of the R-phase, and the formation of tortuous grain boundaries.

Thermokinetic stabilisation of nanocrystalline Cu by ternary approach

ABSTRACT Nanocrystalline alloy design with the synergistic contribution of ‘thermodynamic’ and ‘kinetic’ stabilisation mechanism leads to much superior microstructural stabilisation at elevated temperatures. Ternary Cu98.5W1Zr0.5 (at. %) alloy, synthesised by mechanical milling under cryogenic temperature followed by consolidation through hot pressing at 550°C, has been examined to access the potential of their concurrence. A meager drop in hardness (∼0.5 GPa) confirms the stability of the alloy up to 800°C. The effect of alloy addition has been studied in terms of microstructure alteration, measured by X-ray diffraction, transmission electron microscopy, and Molecular dynamics (MD) simulation. In addition, the shear punch test (SPT) has been employed to assess the mechanical property of the consolidated alloy. Results suggest that the current approach provides a framework en route to designing bulk nanostructured alloys adapting the bottom-up method.

Improved corrosion resistance and mechanical properties of biodegradable Mg–4Zn–xSr alloys: effects of heat treatment, Sr additions, and multi-directional forging

The effects of Sr additions, heat treatment (T4 and T6), and multi-directional forging on the microstructural evolution, mechanical properties and biodegradability of Mg–4Zn–xSr alloys were investigated. Corrosion behavior of the alloys was evaluated by the polarization and hydrogen evolution tests. Shear punch and hardness tests were employed to determine the mechanical properties. It was found that mechanical properties and corrosion resistance of the as-cast Mg–4Zn alloy increased by 0.3 wt% Sr addition. However, further increasing the Sr content not only did not improve the mechanical strength, but also had detrimental effects on the corrosion resistance, due to the increased size and volume fraction of the intermetallic particles. While T4 heat treatment decreased the corrosion current density of Mg–4Zn–0.3Sr alloy from 2.58 to 2.1 μA/cm2, it resulted in some mechanical softening. On the other hand, T6 heat treatment significantly improved mechanical strength of the Mg–4Zn–0.3Sr alloy by about 10 MPa, while its effect on corrosion resistance was minor. Multi-directionally forged Mg–4Zn–0.3Sr alloy also demonstrated improved mechanical and corrosion properties compared to the as-cast condition, which was mainly attributed to the smaller grain size as well as better distribution of the secondary phases.

Hot shear deformation constitutive analysis of fine-grained ZK60 Mg alloy sheet fabricated via dual equal channel lateral extrusion and sheet extrusion

Dual equal channel lateral extrusion (DECLE) process with various passes followed by sheet extrusion process was performed to produce fine-grained ZK60 alloy sheets. The coarse grain structure of the annealed sample after applying sheet extrusion (size: 68 µm) changed to fine grains of 6.0 and 5.2 µm after 3 and 5 passes of DECLE and following extrusion. The hot shear deformation behavior of samples was studied by developing constitutive equations based on shear punch test (SPT) results. SPT was carried out in the temperature range of 200−300 °C and strain rate range of 0.003−0.33 s–1. The activation energy of 125−139 kJ/mol and the stress exponent of 3.5−4.2 were calculated for all conditions, which indicated that dislocation creep, controlled by dislocation climb and solute drag mechanism, acted as the main hot deformation mechanism. It was concluded that material constants of n and Q are dependent on the microstructural factors such as grain size and second phase particle fraction, and the relationship of which was anticipated using a 3D surface curve. Moreover, the similar strong basal texture of extruded sheets gave rise to the same deformation mechanisms during SPT and similar n and Q values for ZK60 alloy.

Influence of ultrasonic impact treatment on microstructure and mechanical properties of nickel-based alloy overlayer on austenitic stainless steel pipe butt girth joint

Ultrasonic impact treatment (UIT) is carried out on the Ni-based alloy stainless steel pipe gas tungsten arc welding (GTAW) girth weld, the differences of microstructure, microhardness and shear strength distribution of the joint before and after ultrasonic shock are studied by microhardness test and shear punch test. The results show that after UIT, the plastic deformation layer is formed on the outside surface of the Ni-based alloy overlayer, single-phase austenite and γ type precipitates are formed in the overlayer, and a large number of columnar crystals are formed on the bottom side of the overlayer. The average microhardness of the overlayer increased from 221 H V to 254 H V by 14.9%, the shear strength increased from 696 MPa to 882 MPa with an increase of 26.7% and the transverse average residual stress decreased from 102.71 MPa (tensile stress) to −18.33 MPa (compressive stress), the longitudinal average residual stress decreased from 114.87 MPa (tensile stress) to −84.64 MPa (compressive stress). The fracture surface has been appeared obvious shear lip marks and a few dimples. The element migrates at the fusion boundary between the Ni-based alloy overlayer and the austenitic stainless steel joint, which is leaded to form a local martensite zone and appear hot cracks. The welded joint is cooled by FA solidification mode, which is forming a large number of late and skeleton ferrite phase with an average microhardness of 190 H V and no obvious change in shear strength. The base metal is all austenitic phase with an average microhardness of 206 H V and shear strength of 696 MPa.

Synthesis of FeCrCoNiCu high entropy alloy through mechanical alloying and spark plasma sintering processes

FeCrCoNiCu high entropy alloy (HEA) was produced through mechanical alloying (MA) and spark plasma sintering (SPS) processes. Using X-Ray diffraction, scanning electron microscopy, differential scanning calorimetry, and shear punch testing, the structural, microstructural, and mechanical properties of the milled and SPSed samples were evaluated. After 50 h of milling, a dual-phase solid solution HEA formed consisting of a major FCC phase and a minor BCC phase. Increasing milling time and repeated deformation of the powders led to increased strain and dislocation density, and eventually, an alloy with a uniform distribution of particles with reduced size was achieved. Sintering of the alloy at 750 °C resulted in the annihilation of the BCC phase and the formation of a sigma phase. Moreover, segregation of the elements due to the different mixing enthalpies led to the formation of a new FCC phase. Results revealed that the SPSed alloy that was properly sintered had a porosity of less than 8%, which resulted in good final mechanical properties such as ultimate shear strength of 300 MPa and ultimate tensile strength of 540 MPa.

A Novel Microshear Geometry for Exploring the Influence of Void Swelling on the Mechanical Properties Induced by MeV Heavy Ion Irradiation.

Small disks are often the specimen of choice for exposure in nuclear reactor environments, and this geometry invariably limits the types of mechanical testing that can be performed on the specimen. Recently, shear punch testing has been utilized to evaluate changes arising from neutron irradiation in test reactor environments on these small disk specimens. As part of a broader effort to link accelerated testing using ion irradiation and conventional neutron irradiation techniques, a novel microshear specimen geometry was developed for use with heavy-ion irradiated specimens. The technique was demonstrated in pure Cu irradiated to 11 and 110 peak dpa with 10 MeV Cu ions. At 11 peak dpa, the Cu specimen had a high density of small voids in the irradiated region, while at 110 peak dpa, larger voids with an average void swelling of ~20% were observed. Micropillar and microshear specimens both exhibited hardening at 11 dpa, followed by softening at 110 dpa. The close alignment of the new microshear technique and more conventional micropillar testing, and the fact that both follow intuition, is a good first step towards applying microshear testing to a wider range of irradiated materials.

Nanocomposite AlCoCrFeNi2.1 high-entropy alloy produced by FSP

In the present work, the nanocomposite AlCoCrFeNi2.1 high-entropy alloy was produced using friction stir processing (FSP). SiC nanoparticles were distributed on the surface via the stirring action imposed by FSP. The size and weight percent of added nanoparticles were 45–60 nm and 3wt.%, respectively. The applied rotating and transverse speeds were 800 rpm and 50 mm/min, respectively. The microstructural evolutions, the hardness changes and the shear properties were evaluated after applying FSP. These studies were carried out using X-ray fluorescence (XRF), optical microscopy, scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDS) and X-Ray diffraction (XRD). Also, the mechanical properties were investigated using Rockwell C and Vickers hardness testing as well as shear punch testing (SPT). The initial microstructure was significantly modified due to the occurrence of dynamic recrystallization as well as Zener pinning applied by nanoparticles. During the FSP, the SiC nanoparticles along with the broken B2 phases were distributed uniformly in the matrix. The microstructural changes resulted in an increase in the hardness and shear strength from 308 HV to 480 HV and 344 MPa to 407 MPa, respectively for initial and FSPed cases.

A comparative study on the microstructural features and mechanical properties of an Mg–Zn alloy processed by ECAP and SSE

The influence of the equal channel angular pressing (ECAP) and simple shear extrusion (SSE) processes on the microstructural and textural developments, as well as mechanical properties of Mg–4Zn alloy was studied. Application of 1, 2, and 4 passes of ECAP and SSE resulted in remarkable grain refinement of the initial microstructure of extruded material. Due to the greater shear strain and finer second phase particles, acting as obstacles to grain growth, smaller grain sizes were developed in the SSEed samples compared to the ECAPed counterparts. The fiber texture component of the extruded alloy was gradually transformed to a shear texture component after 4 ECAP passes, while 1, 2, and 4 passes of SSE produced a semi-fiber texture, in which basal planes were parallel to the longitudinal axis of the processed sample. Due to the applied reversal shear strain to the sample inside the SSE die, the volume fraction of the dynamically recrystallized (DRXed) regions was lower than that in the ECAP process which exerted a one-step shear strain to the sample. Shear punch test (SPT) results indicated that both ECAP and SSE improved the strength of the extruded alloy due to the grain boundary strengthening, texture hardening, and dislocation-dislocation interaction mechanisms. The strength of the SSEed samples was greater than ECAPed specimens, due to the finer grain size, higher volume fraction of un-DRXed grains, and lower Schmid factor of the semi-fiber texture component of the former.