M. T. Pérez-Prado

• PhD, MBA
• Managing Director at IMDEA Materials, Madrid, Spain

The aim of this work is to explore the laser powder bed fusion (LPBF) processability window of the nanocrystalline soft magnetic Finemet alloy. With that purpose, several laser power and scan speed values and a meander scanning strategy were probed to process simple geometry specimens. Good dimensional accuracy was obtained within the entire proces...

The aim of this work is to investigate the formation of an anomalously high fraction of twin boundaries (TBs) during laser directed energy deposition (DED) of a Mg-3Al-1 Zn (wt.%) alloy. With that goal, single tracks are deposited using different combinations of scan speed and powder feed rate. The melt pool dimensions are related to the DED parame...

Magnesium alloys, among the lightest structural materials, represent excellent candidates for lightweight applications. However, industrial applications remain limited due to relatively low strength and ductility. Solid solution alloying has been shown to enhance Mg ductility and formability at relatively low concentrations. Zn solutes are signific...

This work investigates the strain-dependent activation of second-order <c+a> pyramidal slip and other non-basal systems with increasing tensile strain in a Mg-Zn alloy. With that purpose, a polycrystalline solid solution Mg-Zn alloy with ∼2 wt.% Zn (∼0.75 at. %) and with an average grain size of ∼36 μm was processed by casting, hot rolling and subs...

This research aims to study the laser powder bed fusion (L-PBF) processability, the microstructure and the tensile mechanical properties of an AlFeCr alloy at a wide range of temperatures. With this goal, Al-5Fe-6Cr (wt%) pre-alloyed powder was produced by casting and gas atomization. The microstructure of the as-atomized powders and the as-built s...

This work provides unambiguous evidence for the occurrence of icosahedral quasicrystal (iQC) enhanced nucleation during selective laser melting of gas atomized commercially-pure Ni powders. This solidification mechanism, which has only been recently reported in a few alloys and has to date never been observed in pure metals, consists on the solidif...

This work provides unambiguous evidence for the occurrence of icosahedral quasicrystal (iQC) enhanced nucleation during selective laser melting of gas atomized commercially-pure Ni powders. This solidification mechanism, which has only been recently reported in a few alloys and has to date never been observed in pure metals, consists on the solidif...

The objective of this research is to study the effect of the Zr on the L-PBF processability, microstructure, and microhardness of an AlZnMgCu-Zr alloy. Two AlZnMgCu-0.5 and 1.5 wt% Zr pre-alloyed powders were produced by casting followed by gas atomization. In addition, an excess of Mg and Zn was added to the target compositions to compensate for v...

This work investigates the effect of solid solution on ductility and on the activation of individual deformation mechanisms at moderate temperatures and at quasi-static strain rates in Mg-Zn and Mg-Al alloys. With that aim, four solid solution Mg-Zn and Mg-Al binary alloy ingots containing 1 and 2 wt.% solute atoms were subjected to hot rolling and...

This work aims to understand the inefficiency of nanoprecipitates to strengthen a weakly textured, polycrystalline Mg-Gd-Y-Zr alloy. An experimental micromechanical approach consisting on micropillar compression combined with analytical electron microscopy is put in place to analyze the effect of nanoprecipitation on soft and hard basal slip and tw...

The aim of this work is to investigate the interaction of basal dislocations and twin boundaries with ultrafine basal disk-shaped precipitates at the atomic scale in the the peak-aged Mg-1Mn-1Nd-3Zn (wt.%) alloy. With that goal, an experimental approach consisting on micropillar compression of two grains oriented favorably for basal slip and for te...

Selective laser melting (SLM) is rapidly evolving to become a mainstream technology. However, the fundamental mechanisms of solidification and microstructure development inherent to the non-equilibrium conditions of this additive manufacturing method, which differ largely from those typical of conventional processing techniques, remain widely unkno...

Selective laser melting (SLM) is rapidly evolving to become a mainstream technology. However, the fundamental mechanisms of solidification and microstructure development inherent to the non-equilibrium conditions of this additive manufacturing method, which differ largely from those typical of conventional processing techniques, remain widely unkno...

The aim of this work is to investigate the influence of the addition of Cu on the microstructure and on the microhardness of a laser powder bed fusion (L-PBF)-fabricated AlSi10Mg alloy. With this goal, AlSi10Mg+4 wt%Cu pre-alloyed powder was produced by gas atomization. Following a parameter optimization study, dense as-built specimens with a high...

Despite corrosion being commonly seen as a problem to be avoided, applications such as batteries or biodegradable implants do benefit from corrosion‐like phenomena. However, current strategies address corrosion control from a global perspective for a whole component, without considering local adaptations to functionality specifications or inhomogen...

The influence of Zr additions (in the form of ZrH2 particles) on the microstructure and mechanical properties of IN718 Ni-based superalloy manufactured by selective laser melting was explored. Fully dense alloys could be obtained by careful selection of the processing parameters. The addition of ZrH2 did not modify the microstructure of the alloy b...

The influence of Zr additions (in the form of ZrH2 particles) on the microstructure and mechanical properties of IN718 Ni-based superalloy manufactured by selective laser melting was explored. Fully dense alloys could be obtained by careful selection of the processing parameters. The addition of ZrH2 did not modify the microstructure of the alloy b...

The industrial use of laser powder-bed fusion (L-PBF) in turbomachinery is gaining momentum renderingthe inspection and quali?cation of certain post-processing steps necessary. This includes fusiontechniques that allow to print multiple parts separately to take advantage of e.g. various print orientationsand join them subsequently. The main motivat...

The aim of this work is to investigate the fundamentals of dislocation-particle interactions in a Mg-1%Mn-1%Nd (wt.%) (MN11) alloy in order to better understand the limited precipitation strengthening exhibited by this material. A combined approach including micromechanical testing, slip trace analysis, and high resolution transmission electron mic...

It is commonly accepted that prismatic precipitates in Mg alloys are more potent strengtheners than the ones formed on basal planes. However, in most rare-earth (RE) free Mg alloys, precipitation commonly occurs on basal planes. Recent results showed that coupling {102} twinning, aging and detwinning (a process termed TAD) promotes prismatic precip...

The objective of this work is to assess the accuracy of different approaches to represent the microstructure of a polycrystalline sample using EBSD (electron backscatter diffraction) maps of a single external surface as input. To this aim, the stress and strain fields predicted using the finite element method and considering either columnar grains,...

The aim of this work is to investigate the influence of the volumetric energy density (EV) on the microstructure, texture and Vickers hardness of Ti-6Al-4V (wt%) processed by laser powder bed fusion (LPBF), both in the as-built and heat-treated conditions. With this goal, Ti-6Al-4V powder was processed using energy densities ranging between 24.2 an...

The aim is, first, to optimize gas atomization of a γ‐TiAl alloy at the laboratory scale (atomized mass < 150 g) and, second, to investigate the microstructure of the produced powders. Gas atomization variables, such as the gas pressure and the melt temperature, are adjusted to produce the highest yield of particles with sizes smaller than 150 μm....

This work investigates the origin of the simultaneous increase in strength and ductility that takes place in Mg polycrystals alloyed with Al and Zn solutes. With that purpose, twelve polycrystalline binary Mg–Zn and Mg–Al alloys, with up to 2 wt % of alloying additions and average grain sizes comprised between 3 and 42 μm, were prepared by casting,...

In this work electron backscattered diffraction (EBSD)-assisted slip trace analysis and transmission electron microscopy have been utilized to investigate the interaction of basal dislocations with precipitates in the Mg alloys Mg-1%wt.Mn-0.7%wt.Nd (MN11) and Mg-9%wt.Al-1%wt.Zn (AZ91), with the ultimate aim of determining the origin of their poor p...

Modification of alloy compositions is currently widely investigated to improve the processability of nickel based superalloys by selective laser melting (SLM). In several alloys, including Hastelloy X, it has been observed that marginal amounts of specific elements may influence the solidification cracking susceptibility during SLM. This paper desc...

This work analyses the texture and microstructure gradients emerging in a 316L stainless steel processed by selective laser melting, using an island scan strategy, followed by annealing. Laser processing leads to the alignment of different crystallographic directions with the build direction at the mid and top layers, as well as to gradual structur...

In this work electron backscattered diffraction-assisted slip trace analysis was utilized to investigate the origin of the high temperature reversed yield asymmetry in a Mg-rare earth alloy. This material was tested at room and high temperature, in tension and compression, both in the as-extruded condition, in which the alloying elements are in sol...

This study aims at determining the strength of a fully lamellar Ti-45Al-2Nb-2Mn (at.%) + 0.8 (vol.%)TiB2 alloy, with nanoscale lamellar thicknesses. With this aim, the average lamellar thickness of a centrifugally cast alloy was refined one order of magnitude, down to just a few nanometers, by water quenching, followed by a low temperature ageing t...

The effect of prismatic plates on the mechanical behaviour at low and high temperature of a Mg-1 wt.% Mn- 1 wt%Nd alloy was determined. For this purpose, a weakly textured extruded bar, exhibiting similar values for the critical resolved shear stresses of the various deformation systems, was annealed at 275 °C for different time periods. During the...

The aim of this study is to determine the influence of lamellar orientation on the strength and operative deformation mechanisms of a fully lamellar Ti-45Al-2Nb-2Mn (at.%) + 0.8(vol.%) TiB2 (Ti4522XD) alloy. With this aim, micropillars with lamellae oriented at 0°, 45° and 90° with respect to the loading direction were compressed at room temperatur...

This work demonstrates that room temperature (RT) ferromagnetism might be triggered in pure hafnium (Hf), a classic paramagnet, by severe plastic deformation (SPD) via high pressure torsion (HPT). The origin of this phenomenon is elucidated by a combined approach including density functional theory (DFT) calculations and transmission electron micro...

The aim of this work was to investigate the influence of the precipitate distribution on the microstructure and on the room and high temperature mechanical properties of an age-hardenable aluminium AA6082 alloy following severe straining by high-pressure torsion (HPT). With this goal, specimens in the as-cast and T6 peak-aged conditions were proces...

This work shows that plastic deformation may trigger a spontaneous magnetization at ambient temperature in pure paramagnetic metals such as zirconium, titanium and magnesium. Subsequent strain relaxation by annealing leads to a decrease of the permanent magnetization. We propose that the lattice distortions associated with dislocations promote the...

The aim of the present work is to assess the activity of the dominant deformation slip systems in the commercial cast alloy Mg-9%wt. Al-1%wt. Zn (AZ91) in the as-rolled, solution treated and peak-aged conditions. It is well known that the microstructure of this alloy is formed by α-Mg grains, β-Mg17Al12 phases which precipitate mostly as plates par...

Ceramic AlN nanoparticles were added to a melt of magnesium alloy Elektron21 assisted by mechanical stirring and sonication for deagglomeration. The produced nanocomposite was investigated to determine its metallography, hardness, physical and mechanical properties, and compression creep resistance. Creep tests at a constant temperature of 240 °C a...

Tensile experiments were performed on a rolled AZ31 alloy in an SEM at 323K (50°C), 423K (150°C), and 523K (250°C) in order to analyze the deformation mechanisms in-situ. Electron backscatter diffraction (EBSD) was performed both before and after deformation. The mechanical anisotropy was considerably reduced with temperature. Extension twinning wa...

Nanoscale particles have been uniformly dispersed in a magnesium alloy, yielding composites with record-breaking strengths - and raising the prospect of using magnesium as a lightweight metal for structural applications.

Tensile twinning is a key deformation mode in magnesium and its alloys, as well as in other hcp metals. However, the fundamentals of this mechanism are still not fully understood. In this research, instrumented nanoindentation and crystal plasticity finite element simulations are utilized to investigate twin formation and propagation in pure Mg. Wi...

The aim of this paper is to highlight the unique capabilities of electron backscattered diffraction-assisted trace analysis during in situ SEM mechanical testing of metals in order to get a better understanding of plasticity at the microscale. The technique allows for the direct observation of different deformation mechanisms, such as slip and twin...

A limiting factor of high pressure die cast (HPDC) Mg alloys is the presence of porosity, which has a detrimental effect on the mechanical strength and gives rise to a large variability in the ductility. The application of hydrostatic pressure after casting is known to be beneficial to improve the mechanical response of HPDC Mg alloys. In this stud...

The mechanical behaviour in tension and compression of an extruded Mg–1 wt.% Mn–1 wt.% Nd (MN11) alloy was studied along the extrusion direction in the temperature range −175 °C to 300 °C at both quasi-static and dynamic strain rates. Microstructural analysis revealed that the as-extruded bar presents a recrystallized microstructure and a weak text...

The aim of this paper is to elucidate the origin of the transition from twinning to slip dominated flow in pure Mg. With that purpose, two polycrystals with average grain sizes of 19 and 5 μm were prepared by rolling and annealing and they were tested in compression along the rolling direction at strain rates ranging from 10−3 to 10−5 s−1 and at te...

The effect of temperature on the main deformation mechanisms of pure magnesium (Mg) was investigated using nanoindentation combined with atomic force microscopy, electron backscatter diffraction and finite element crystal plasticity simulations. While twinning is clearly apparent near the indents performed at room temperature, almost no twinning ac...

Several controversies regarding the mechanical behavior of Mg at moderate temperatures and quasi-static strain rates remain unsolved. In particular, the fundamental reasons behind the anomalous grain size dependence of the flow stress during power law slip-dominated creep as well as of the observed decrease in the strain anisotropy with increasing...

The aim of this work is to investigate the effect of grain size on slip activity, a critical issue for materials design that remains unsolved. Three pure magnesium polycrystals with average grain sizes (d) of 36, 19 and 5 μm and with very similar textures and grain boundary (GB) misorientation distributions were designed by selecting appropriate ro...

This chapter discusses superplasticity, which is the ability of a polycrystalline material to exhibit very high tensile elongations prior to failure. Since the first observations of this phenomenon, superplasticity has been extensively studied in metals. It is believed that both the arsenic bronzes, used in Turkey in the Bronze Age (2500 BC), and t...

An inverse optimization strategy based on crystal plasticity finite element simulations of polycrystals was used to obtain the critical resolved shear stresses of two Mg–1%Mn alloys containing neodymium from macroscopic experimental data. It was found that, with respect to pure Mg, the presence of Nd increases the CRSSbasal, CRSStwinning, and the C...

An extruded Mg-1 wt pct Mn-1 wt pct Nd (MN11) alloy with a recrystallized microstructure and a weak texture was subjected to different thermal treatments at temperatures ranging from 548 K to 673 K (275 °C to 400 °C) for time intervals between 1 and 45 hours. Room-temperature mechanical tests were carried out in tension and compression at 10−3 s−1...

This work aims to contribute to a further understanding of the fundamentals of crystallographic slip and grain boundary sliding in the γ-TiAl Ti–45Al–2Nb–2Mn (at%)–0.8 vol%TiB2 intermetallic alloy, by means of in situ high-temperature tensile testing combined with electron backscatter diffraction (EBSD). Several microstructures, containing differen...

One of the main limiting factors in the development of new magnesium (Mg) alloys with enhanced mechanical behavior is the need to use vast experimental campaigns for microstructure and property screening. For example, the influence of new alloying additions on the critical resolved shear stresses (CRSSs) is currently evaluated by a combination of m...

The effect of grain boundary (GB) misorientation (theta) on twinning in a Mg AZ31 alloy is investigated using a three-dimensional (3-D) experimental and modeling approach, in which 3-D electron backscattered diffraction is performed in a volume consisting of a central grain, favorably oriented for twinning, and surrounded by three boundaries, with...

Two Mg-1 wt pct Mn alloys containing 0.5 wt pct and 1 wt pct Nd have been processed by indirect extrusion at temperatures ranging from 548 K (275 °C) to 633 K (360 °C) and speeds between 2.8 and 11 mm/s. The microstructure and the texture of the extruded bars were analyzed in order to understand the effect of the processing parameters and of the ra...

The mechanical behavior of an extruded magnesium–manganese alloy containing 1 wt% of neodymium (MN11) has been investigated at temperatures ranging from room temperature to 400 °C at both quasi-static and dynamic rates. Conventional ex-situ tests, carried out in compression along the extrusion axis (EA), have been combined with in-situ tests in a s...

Currently, most magnesium lightweight components are fabricated by casting as this process is cost effective and allows forming parts with complex geometries and weak textures. However, cast microstructures are known to be heterogeneous and contain unpredictable porosity distributions, which give rise to a large variability in the mechanical proper...

The effect of heat treatments on an as-HIPed γ-TiAl intermetallic alloy was examined. Duplex and fully lamellar microstructures were generated by annealing and subsequently characterized. The relationship between the microstructures and the deformation mechanisms of the intermetallic alloy was studied by means of in-situ tensile experiments perform...

This paper presents new data and a summarization of earlier work, especially by the authors, regarding the large strain deformation (generally severe plastic deformation) of pure zirconium, generally at elevated temperatures (300–800 °C range). It appears clear, now, that Zr deforms by classic five-power-law creep. Large strain deformation revealed...

The technique of high pressure torsion (HPT) has been widely used to refine the microstructure of many metallic materials, especially pure metals and disordered alloys. Comparatively fewer studies have, however, been carried out in intermetallics. γ-TiAl alloys are envisioned as high potential materials to replace Ni superalloys in some turbine com...

The effect of the applied stress on the deformation and crack nucleation and propagation mechanisms of a γ-TiAl intermetallic alloy (Ti-45Al-2Nb-2Mn (at. pct)-0.8 vol. pct TiB2) was examined by means of in situ tensile (constant strain rate) and tensile-creep (constant load) experiments performed at 973 K (700 °C) using a scanning electron microsco...

Pure Zn was processed by high pressure torsion (HPT) at room temperature in order to evaluate the effect of this severe plastic deformation (SPD) technique on materials processed at high homologous temperatures. HPT leads to the development of coarse grains with orientations belonging to a basal fiber by discontinuous dynamic recrystallization (DDR...

An extruded Mg–1Mn–1Nd (wt%) (MN11) alloy was tested in tension in an SEM at temperatures of 323 K (50°C), 423 K (150°C), and 523 K (250°C) to analyse the local deformation mechanisms through In situ observations. Electron backscatter diffraction was performed before and after the deformation. It was found that the tensile strength decreased with i...

Highly-textured, rolled AZ31 sheet material shows a significant drop in the plastic anisotropy (r-value; r=ew/et) in tension between 25°C and 200°C. This behavior was initially explained as a result of the increased activity of non-basal slip with increased temperature. Other authors suggested, however, that the mechanism responsible for this pheno...

The effect of stress on the deformation and crack nucleation and propagation mechanisms of a γ-TiAl intermetallic alloy (Ti-45Al-2Nb-2Mn (at.%) - 0.8v.%TiB2) was studied by means of in situ tensile (constant strain rate) and tensile-creep (constant load) experiments performed at 973 K inside a scanning electron microscope (SEM). The evolution of th...

The dynamic behavior of the die-cast Mg-6 % Al-0.5 % Mn and Mg-9 % Al-1 % Zn alloys has been investigated in a wide range of temperatures and compared to the quasi-static behavior. It has been found that, at high strain rates, these alloys possess very good energy absorption capacity and that twinning is significantly enhanced. The small variabilit...

IntroductionExperimentalResultsDiscussionConclusions Acknowledgements

The high strain rate behaviour of magnesium alloys is of great interest to automotive, aerospace and/or defence industries because some critical components should have the proper mechanical properties to work under crash or impact conditions. In the current study, results from an extensive experimental program are presented. The uniaxial mechanical...

The work carried out by the authors over the last decade on the processing, microstructural characterization and the mechanical behaviour of Mg alloys is reviewed. In particular, the potential for grain refinement and for the development of specific textures of large strain hot rolling (LSHR), equal channel angular pressing (ECAP) and accumulative...

Acrystal plasticity continuum model with differentiated self- and cross- hardeningmechanisms for twin and slip systems has been utilized to predict the slip/twin activities and texture evolution in a rolled and annealed Mg-3%Al-1%Zn sheet compressed along the rolling direction (RD) and tensile tested along the normal direction (ND). The contributio...

Lightweight magnesium alloys, such as AZ31, constitute alternative materials of interest for many industrial sectors such as the transport industry. For instance, reducing vehicle weight and thus fuel consumption can actively benefit the global efforts of the current environmental industry policies. To this end, several research groups are focusing...

An AZ31 rolled sheet alloy has been tested at dynamic strain rates (∼103 s-1) at 250°C up to various intermediate strains before failure in order to investigate the predominant deformation and restoration mechanisms. In particular, tests have been carried out in compression along the rolling direction (RD), in tension along the RD and in compressio...

The microstructural evolution of an AZ31 rolled sheet during dynamic deformation at strain rates of ∼103 s−1 has been investigated by electron backscatter diffraction, X-ray and neutron diffraction. The influence of orientation on the predominant deformation mechanisms and on the recovery processes taking place during deformation has been systemati...

A coarse-grained (CG) Al6061 alloy after solution treatment is subjected to high pressure torsion at room temperature resulting in the formation of a homogeneous ultra-fine grained (UFG) microstructure with average grain size of 170nm. Tensile tests are performed at room and liquid nitrogen temperatures for both CG and UFG conditions. Analysis of t...

The alpha (α) to omega (ω) plus beta (β) phase transformation in pure zirconium by high-pressure torsion depends on the orientation of the polycrystalline aggregate with respect to the applied stress. The transformation can be triggered without any applied shear at 1 GPa when the pressure is perpendicular to the c-axes. Twinning plays a major role...

A solution treated coarse grained (CG) Al6061 was subjected to high pressure torsion (HPT) at room temperature resulting in the formation of a homogeneous ultra-fine grained (UFG) microstructure with an average grain size of 170 nm. Tensile tests were performed at room temperature (RT) and liquid nitrogen temperature (LNT). The as-HPT UFG Al6061 al...

Accumulative roll bonding (ARB) has been considered as one of the promising techniques for fabrication of ultra-fine grained (UFG) metallic materials. The ARB process consists of several cycles of cutting, stacking, and rolling of metal sheets, so very high strains can be induced in the material resulting in significant grain refinement and in the...

This paper analyzes the influence of Nb on the shear-induced α → ω → β transformation taking place when processing Zr by high pressure torsion (HPT) under suitable conditions of pressure and shear. With that purpose, pure Zr and Zr–2.5%Nb were processed by HPT at room temperature and at pressures ranging from 0.25 to 6 GPa using 5 anvil turns. Nb c...

The deformation and fracture mechanisms of a nearly lamellar Ti-45Al-2Nb-2Mn (at. pct) + 0.8 vol pct TiB2 intermetallic, processed into an actual low-pressure turbine blade, were examined by means of in situ tensile and tensile-creep experiments performed inside a scanning electron microscope (SEM). Low elongation-to-failure and brittle fracture we...

Commercially pure (CP) Ti was subjected to a complex severe plastic deformation (SPD) processing route consisting of equal channel angular pressing, swaging and drawing, resulting in the formation of a homogeneous ultra-fine-grained (UFG) microstructure showing a very high strength. The significant anisotropy of mechanical properties found in the p...

The microstructure and mechanical properties of austenitic stainless steel 316 LVM (Low Vacuum Melting) blasted with either small and rounded ZrO2 particles or larger and angular shaped Al2O3 particles are analysed through magnetic force microscopy, synchrotron radiation diffraction and ultramicroindentation techniques. It is shown that blasting ca...

Zirconium at normal conditions (room temperature and atmospheric pressure) has an HCP structure with lattice parameters a = 3.2313 Å and c = 5.1477 Å (α-phase). During loading under hydrostatic conditions in diamond anvil cells, a transition from the α -phase to an ω-phase occurs at a pressure between 2 and 6 GPa and from ω to β (bcc) at 30 GPa. It...

The effect of the press geometry in the α to ω + β transformation in pure Zr by high pressure torsion (HPT) was investigated. Specimens were processed in constrained and unconstrained setups using a wide range of applied pressures and 5 anvil turns. The resulting microstructures were characterized by X-ray diffraction (XRD), transmission electron m...

The mechanical behavior of an AZ31 Mg sheet has been investigated at high strain rate (103 s−1) and compared with that observed at low rates (10−3 s−1). Dynamic tests were carried out using a Hopkinson bar at temperatures between 25 and 400 °C. Tensile tests were carried out along the rolling and transverse directions and compression tests along th...

A new SPD technique, equal channel angular pressing with parallel channels (ECAP-PC), has been recently developed. The method has a few advantages over conventional ECAP. In this work, the ECAP-PC is applied to the Al alloys 6061 and 6063. The AAl6061 is subjected to ECAP-PC at 100°C for 4 passes. The Al6063 alloy is subjected to ECAP-PC at 100°C a...

This work focuses on the mechanical properties and on the deformation behavior of commercially pure (CP) Ti processed via a novel SPD route. The material was subjected to equal-channel angular pressing at 450°C for 8 passes using the processing route Bc. Then the rods were subjected to swaging and drawing with the total accumulated strain of ∼80%....

Recently pure omega plus bcc Zr was fabricated for the first time through the simultaneous application of compression and shear to pure alpha Zr by high pressure torsion. This phase was found to be stable under ambient conditions after processing. Here the thermal stability of the pure bcc Zr thus fabricated is analyzed using differential scanning...

In the current contribution the mechanical behaviour at high strain rates of AZ31 magnesium alloy sheet is studied. Uniaxial deformation properties were studied by means of tensile split Hopkinson pressure bar (SHPB) at different temperatures. The influence of the strain rate and temperature on the deformation mechanisms was investigated by means o...

Shear stresses are shown to induce the alpha (hcp) to omega (simple hexagonal) plus beta (bcc) transformation in pure Zr at room temperature. The beta Zr thus fabricated is stable at 1 atm and room temperature. This phase has so far only been found to occur at high pressures (P>30 GPa) and/or at high temperatures (T>1135 K). This experimental obser...