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At least 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Surface scattering properties estimated from modeling airborne multiple emission angle reflectance data

Here, researchers apply the Hapke function to airborne bidirectional reflectance data collected over three terrestrial surfaces. The objectives of the study were to test the range of natural surfaces that the Hapke model fits and to evaluate model parameters in terms of known surface properties. The data used are multispectral and multiple emission angle data collected during the Geologic Remote Sensing Field Experiment (GRSFE) over a mud-cracked playa, an artificially roughened playa, and a basalt cobble strewn playa at Lunar Lake Playa in Nevada. Airborne remote sensing data and associated field measurements were acquired at the same time. The airborne data were acquired by the Advanced Solid State Array Spectroradiometer (ASAS) instrument, a 29-spectral band imaging system. ASAS reflectance data for a cobble-strewn surface and an artificially rough playa surface on Lunar Lake Playa can be explained with the Hanke model. The cobble and rough playa sites are distinguishable by a single scattering albedo, which is controlled by material composition; by the roughness parameter, which appears to be controlled by the surface texture and particle size; and the symmetry factor of the single particle phase function, which is controlled by particle size and shape. A smooth playa surface consisting of compacted, fine-grained particles has reflectance variations that are also distinct from either the cobble site or rough playa site. The smooth playa appears to behave more like a Lambertian surface that cannot be modeled with the Hapke function.

Guinness, Edward A.↗
DOE OSTI2021

Surface and subsurface characterization of laser-interference structured Ti6Al4V

Ti6Al4V specimens were exposed to high-energy laser pulses of 1.24 J/cm 2 fluences per pulse using a two-beam optical configuration to attain laser-interference. In addition to the formation of periodic surface textures by laser-interference, scanning electron microscope (SEM) images demonstrated several microstructural changes on the surface processed. Moreover, the surface and subsurface of Ti6Al4V specimens were characterized for the as-received and laser-interference processed conditions using x-ray photoelectron spectroscopy (XPS) and electron energy dispersive spectroscopy (EDS). The XPS data showed that this laser technique is effective at removal of surface contaminants for Ti6Al4V. The XPS analysis also revealed the formation of an oxy-nitride layer on the laser treated material. Finally, the microstructure analysis indicates that grain refinement, dendrite and twin structures were found near the surface due to laser processing.

36 MATERIALS SCIENCE↗
NASA NTRS1977

Laboratory duplication of comb layering in the Rhum pluton

A description is provided of the texture of harrisite comb layers, taking into account the results of crystallization experiments at controlled cooling rates, which have reproduced the textural change from 'cumulate' to comb-layered harrisite. Melted samples of harrisite were used in the dynamic crystallization experiments considered. The differentiation of a cooling rate run with respect to olivine grain size and shape is shown and three possible origins of hopper olivine in differentiated crystallization runs are considered. It is found that olivine nucleation occurred throughout cooling, except for the incubation period during early cooling. The elongate combed olivines in harrisite apparently grew as the magma locally supercooled to at least 30 C. It is suggested that the branching crystals in most comb layers, including comb-layered harrisite, probably grew along thermal gradients.

Donaldson, C. H.↗
NASA NTRS1989

Petrology and thermal history of type IA chondrules in the Semarkona (LL3.0) chondrite

Detailed petrologic studies have been made of 15 type IA, Fe-poor, porphyritic olivine chondrules in Semarkona (LL3.0). Major and minor element concentrations in olivines, pyroxenes, and mesostases, and bulk composition so the chondrules are measured along with zoning profiles in the olivine and pyroxene crystals. The mineral compositions and textures are best interpreted in terms of closed system crystallization in which the olivines and pyroxenes crystallized in situ from a melt corresponding to the bulk composition of the chondrule. Relict olivine grains are not found in the chondrules. Crystallization probably occurred at a cooling rate of the order of 1000 C/hr. Precursor materials of the chondrules were composed of two components, one refractory Ca-, Al-, and Ti-rich, and one less refractory Si-, Fe-, Cr-, and Mn-rich. The evidence is consistent with Semarkona being one of the least metamorphosed ordinary chondrites.

Jones, R. H.↗
NASA NTRS1993

Cathodoluminescence observations of in situ aqueous destruction of chondrules in the Murchison CM chondrite

A low-power cathodoluminescence (CL) mosaic of a 1x2 cm section of the Murchison CM chondrite contains chondrules of two types: one contains olivines with red CL and is thought to be the equivalent of group A chondrules of Sears et.; and one without observable CL, which is probably equivalent to their group B chondrules. Both types of chondrule contain dust mantles with a characteristic uniform red CL due to very fine-grained forsterites, but the mantles of group A chondrules have a complex internal structure and are much thicker than the relatively thin rims on the group B chondrules. The variety of internal textures and the progressive integration of the objects with the surrounding matrix suggests to us that these features are large group A chondrules in the process of being destroyed by aqueous alteration. Prior to aqueous alteration, group A chondrules in CM chondrites were larger than group B chondrules, which is contrary to the situation in ordinary chondrites and were apparently destroyed more rapidly than group B chondrules by aqueous alteration.

Sears, Derek W. G.↗
NASA NTRSDate not supplied

Assessing the Effects of Various Surface Textures and Features on Turbulent Heat Transfer in Hypersonic Flight

Experiments were conducted in the NASA Ames Hypervelocity Free Flight Aerodynamic Facility (ballistic range) to quantify the effects on turbulent convective heat transfer of distributed surface roughness, and of isolated features, representative of thermal protection systems on atmospheric entry vehicles. The surface textures and features were applied on the conic frusta of 45o sphere-cone models having a nose-to-base radius ratio of 0.5, similar to the forebody geometry of the Galileo and Pioneer-Venus entry probes. Test conditions were selected to provide turbulent roughness Reynolds numbers, k+, in the ranges expected for outer planet entry missions. Turbulent flow on the conic frustum was achieved by tripping the flow on the sphere-segment nose cap with distributed surface roughness, created by sand-blasting the nose cap. Surface textures included distributed, acreage, roughness, as well as cavity and groove discrete features. The majority of the data to be presented are results for distributed roughness, which includes both random, sand-grain-like roughness, and regular pattern roughness. The pattern roughness was designed to represent the roughness on woven thermal protection system materials, such as NASA’s 3-D Medium Density Carbon Phenolic (3MDCP), also known as HEEET, developed by the Heatshield for Extreme Entry Environments Technology project. The pattern roughness tested is a 3-D wavy surface, and includes three different roughness element height-to-spacing ratios representative of two configurations of 3MDCP, and spanning ratios measured both before, and after, ablation in an arc jet test facility. The patterns tested in the ballistic range were laser-etched on metal models, and represented an idealized version of the real-world materials in which each roughness element was nearly identical. Additional tests were performed wherein the laser-etched patterns were degraded by sand-blasting with various sized grit media, to produce regular patterns with superimposed irregular roughness, more representative of flight materials. Results of each will be compared. The discrete features tested included cylindrical cavities and rectangular grooves of various width-to-depth ratios. Cavities represent either heatshield damage, such as from micro-meteoroid and orbital debris (MMOD) damage, or from designed penetrations, such as on the Genesis sample return capsule. The grooves were scaled representations of seams between segments of HEEET material in a notional tiled thermal protection system. The tests examined the effects on turbulent heating downstream of the isolated features. The tests were conducted at speeds between 3 km/s and 4 km/s in air between 0.15 atm and 0.25 atm (Mach numbers between 9 and 12). Roughness Reynolds numbers, k+, ranged from 12 to 70 for the sand roughness, and as high as 200 for the pattern roughness. Boundary-layer parameters required for calculating k+ were evaluated using computational fluid dynamics simulations using the DPLR (Data Parallel Line Relaxation) code. Each model included both rough- and smooth-wall segments, and heat transfer augmentation factors were determined as the ratio of the rough-wall to smooth-wall heat flux measured on each test.

hypersonic↗
NASA NTRSDate not supplied

New Directions in the Quest for Unaltered Ci-Like Material From the Early Solar System

CI meteorites have bulk chemical compositions closely matching the solar photosphere (except volatiles) and thus are considered to represent the starting composition of the Solar System. The return of CI-like samples from asteroid (162173) Ryugu by Hayabusa2 has greatly bolstered studies of CI. However, both CI and the Ryugu samples are CI1, i.e., they were extensively altered by aqueous fluids on their parent bodies so the mineralogy, textures, and oxygen isotope compositions of their CI3 precursors have been obscured. Fortunately, they contain rare remnants of primordial minerals in the form of small anhydrous silicate and Ca-Al-rich grains, and detailed petrologic and isotopic studies of these grains have helped elucidate the nature of their precursors. Here, we continue our work on petrologic and isotopic studies of such phases in Ryugu particle C0137.

C A Goodrich↗
DOE OSTI2025

Microstructural Evolution of Steel During Magnetic Field-Assisted Processing

Advancing magnetic field-assisted processing, as an energy-efficient method for tailoring steel microstructures, requires a thorough understanding of how the high magnetic field impacts microstructural evolution, particularly its effect on prior austenite grain structures. The current investigation of a near-eutectoid composition, Fe-C alloy, uses electron backscatter diffraction to examine the morphology and orientation of martensite and pearlite microstructures, and to reconstruct the parent austenite microstructures present during equivalent heating under varied magnetic field strengths (0-T, 2-T, 5-T, and 9-T). It was observed that the magnetic field has a negligible effect on martensite lath/block width, slightly decreases prior austenite grain size, and increases the fraction of austenite grains with annealing twins. Additionally, the magnetic field increases the phase fraction of proeutectoid ferrite but has a negligible effect on pearlite block size and the distribution of boundary misorientation angles. No preferred texture was induced by the magnetic field, regardless of the applied field direction, in the proeutectoid ferrite phase or the martensite and prior austenite microstructures. Furthermore, the observed results contradict previous literature, and the differences are discussed.

Magnetic Materials↗
DOE OSTI2020

Chemo‐mechanical Alterations Induced From CO 2 Injection in Carbonate‐Cemented Sandstone: An Experimental Study at 71 °C and 29 MPa

Abstract Carbon capture, utilization, and storage may lead to mechanical degradation of the subsurface reservoir from fluid‐rock interaction, which could lead to wellbore instability or reservoir compaction. To better understand potential relationship between mechanical degradation with various carbonate cement textures and compositions in sandstone reservoirs, six flow‐through experiments were conducted. Formation water (TDS = 5,390 mg/L) enriched with CO 2 flowed through two types of Pennsylvanian Morrow B Sandstone: an ankerite‐siderite‐cemented sandstone (disseminated cement texture) and a calcite‐cemented sandstone (poikilotopic cement texture). The experiments produced little change in permeability in the ankerite‐siderite‐cemented sandstone, but permeability increased up to more than 1 order of magnitude in the calcite‐cemented sandstone. Ultrasonic measurements and cylinder‐splitting tests (also known as Brazilian tests) suggested negligible mechanical degradation of the ankerite‐siderite‐cemented sandstone. Variable changes, with significant mechanical degradation in the static moduli, were observed in the calcite‐cemented sandstone. Thus, dissolution of the disseminated ankerite‐siderite cement (0.28–0.30%) had minimal impact on modifying the flow network and the mechanical integrity of the sandstone, whereas dissolution of the poikilotopic calcite cement (0.89–1.13%, quantified with fluid chemistry and visualized with X‐ray microcomputed tomography) impacted the mechanical strength of the sandstone by disconnecting framework grains. With the high water‐to‐rock mass ratios (7.3–8.2) and number of pore volumes (147–675) employed in these experiments, potential risks are most relevant to regions near injection wells. Ultimately, the chemo‐mechanical effects induced by CO 2 injection are strongly influenced by the cement texture and composition and the burial history of the reservoir rock.

Wu, Z.↗
NASA NTRS1972

Apollo 14 breccias - General characteristics and classification.

The Apollo 14 breccias are complex and are characterized by a wide range of clast types and textures. The principal fragment types in the breccias are (1) hornfelsed noritic microbreccias; (2) micronorite hornfels; (3) devitrified glass; and (4) ophitic and other kinds of basalt. Based on fragment population, nature of the matrix, grain size and porosity, metamorphic history, and bulk chemical composition, the Apollo 14 breccias can be classified chiefly into regolith microbreccias, Fra Mauro breccias, and spherule-rich microbreccias. Further subdivisions are based principally on the interpretation of metamorphic history. Twenty-six Apollo 14 breccias have been so classified. The complex fragment types contained in Apollo 14 breccias represent multiple episodes of heating and fragmentation. They probably are pre-Imbrian and were not produced by the impact effects of a single event. The variability of their fragment populations is important in the interpretation of pre-Imbrian geologic history.

Chao, E. C. T.↗
NASA NTRS2023

Petrological Traverse of the Olivine Cumulate Séítah Formation at Jezero Crater, Mars: A Perspective From SuperCam Onboard Perseverance

Séítah is the stratigraphically lowest formation visited by Perseverance in the Jezero crater floor. We present the data obtained by SuperCam: texture by imagery, chemistry by Laser-Induced Breakdown Spectroscopy, and mineralogy by Supercam Visible and Infrared reflectance and Raman spectroscopy. The Séítah formation consists of igneous, weakly altered rocks dominated by millimeter-sized grains of olivine with the presence of low-Ca and high-Ca pyroxenes, and other primary minerals (e.g., plagioclase, Cr-Fe-Ti oxides, phosphates). Along a ∼140 m long section in Séítah, SuperCam analyses showed evidence of geochemical and mineralogical variations, from the contact with the overlying Máaz formation, going deeper in the formation. Bulk rock and olivine Mg#, grain size, olivine content increase gradually further from the contact. Along the section, olivine Mg# is not in equilibrium with the bulk rock Mg#, indicating local olivine accumulation. These observations are consistent with Séítah being the deep ultramafic member of a cumulate series derived from the fractional crystallization and slow cooling of the parent magma at depth. Possible magmatic processes and exhumation mechanisms of Séítah are discussed. Séítah rocks show some affinity with some rocks at Gusev crater, and with some Martian meteorites suggesting that such rocks are not rare on the surface of Mars. Séítah is part of the Nili Fossae regional olivine-carbonate unit observed from orbit. Future exploration of Perseverance on the rim and outside of the crater will help determine if the observations from the crater floor can be extrapolated to the whole unit or if this unit is composed of distinct sub-units with various origins.

Mars 2020↗
NASA NTRS1992

TEM studies of a circumstellar rock

Reported here is the discovery of crystals of titanium carbide in a grain of silicon carbide which formed as a circumstellar dust particle in the atmosphere of a carbon-rich star. Just as in the case of terrestrial rocks, whose assemblage of minerals gives us clues to the composition and conditions of the environment in which they formed, the titanium carbide crystals and their textural relationship to the silicon carbide give us important clues to the nature of the stellar atmosphere in which they formed. From microscopic studies of the relationships between the atomic planes of the silicon carbide and the titanium carbide, we can show that the titanium carbide cannot have existed as already-formed crystals in a gas around which silicon carbide subsequently condensed. An alternative possibility is that both minerals grew quickly and simultaneously from condensing gas in the rapidly cooling and expanding stellar atmosphere. Other microscopic features of the silicon carbide, such as abundant atomic layer disorder and crystal twinning, similarly suggest rapid grain growth. However, another possibility is that the titanium carbide grew inside of the silicon carbide by diffusion of titanium atoms. Our calculations suggest that this scenario is less likely, given the relatively short times (a year or less) for which stellar condensates can be expected to be exposed to temperatures high enough to make diffusion sufficiently rapid.

Bernatowicz, Thomas J.↗
DOE OSTI2021

Shear assisted processing and extrusion of enhanced strength aluminum alloy tubing

Hollow extrusions are used in many industries to make strong, lightweight, and affordable structures. Shear Assisted Processing and Extrusion (ShAPE) enables the extrusion of many alloys, often with noteworthy properties. In this investigation, ShAPE was used to extrude 1 and 2 mm wall tubes of aluminum alloy 6063 measuring 12 mm in diameter at extrusion speeds up to 3.8 m/min. This speed is 10 and 15 times faster than has been reported for any alloy using ShAPE and friction stir back extrusion, respectively. Increasing the extrusion speed from 0.7 to 3.8 m/s resulted in using 68% less process energy at steady state. Microstructural analysis and tensile testing were performed on as-extruded tubes and tubes with a direct T5 heat treatment. Grain refinement from 65 µm to below 20 µm was observed. Growth of macroscale Mg 2 Si strengthening precipitates was not observed. ShAPE processing resulted in recrystallization, and extrusion speed was shown to influence final extrudate texture. Here, transmission electron microscopy analysis revealed that the as-extruded microstructure was free of nanoscale ß" strengthening precipitates. Nanoscale ß" was prominent in direct-aged (T5) ShAPE tubes, similar to a slightly over-aged conventional T6 microstructure. As-extruded tubes had ultimate tensile strengths on par with conventional T5 extrusions and approximately double the total elongation. Tubes that underwent a T5 heat treatment had yield and ultimate strengths averaging 198 and 234 MPa, respectively, with an average total elongation of 11%. The tensile test results are comparable to a conventional T6 heat treatment, but without the solutionization heat treatment step. Mechanical properties either remained flat or improved with increased extrusion speed, which suggests that ShAPE can be scaled up to an industrial process to create energy- and economically efficient high-strength extrusions.

36 MATERIALS SCIENCE↗
NASA NTRS2014

Looking for a Source of Water in Martian Basltic Breccia NWA 7034

The recently described martian meteorite NWA 7034 has high water content compared to other SNC meteorites. Deuterium to hydrogen isotope ratio measurements indicates that there are two distinct delta-D components in NWA 7034, a low temperature (150-500degC) light component around -100per mille and a high temperature (300-1000degC) heavy component around +300per mille. NWA 7034 contains iron-rich phases that are likely secondary aqueous alteration products. They are commonly found as spheroidal objects of various sizes that are often rich in Fe-Ti oxides and possibly iron hydroxides. Iron oxides and oxyhydroxides are very common in weathered rocks and soils on Earth and Mars and they are important components of terrestrial and Martian dust. In NWA 7034 iron-rich phases are found throughout the fine-grained basaltic groundmass of the meteorite. The total amount of martian H2O in NWA 7034 is reported to be 6000 ppm, and in this study we attempt to determine the phase distribution of this H2O by texturally describing and characterizing hydrous phases in NWA 7034, using Fourier transform infrared spectrometry (FTIR) and transmission electron microscopy (TEM).

Muttik, N.↗
NASA NTRS2019

The unexpected surface of asteroid (101955) Bennu

NASA’S Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft recently arrived at the near-Earth asteroid (101955) Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth1. Bennu is a low-albedo B-type asteroid2 that has been linked to organic-rich hydrated carbonaceous chondrites3. Such meteorites are altered by ejection from their parent body and contaminated by atmospheric entry and terrestrial microbes. Therefore, the primary mission objective is to return a sample of Bennu to Earth that is pristine—that is, not affected by these processes4. The OSIRIS-REx spacecraft carries a sophisticated suite of instruments to characterize Bennu’s global properties, support the selection of a sampling site and document that site at a sub-centimetre scale5,6,7,8,9,10,11. Here we consider early OSIRIS-REx observations of Bennu to understand how the asteroid’s properties compare to pre-encounter expectations and to assess the prospects for sample return. The bulk composition of Bennu appears to be hydrated and volatile-rich, as expected. However, in contrast to pre-encounter modelling of Bennu’s thermal inertia12 and radar polarization ratios13—which indicated a generally smooth surface covered by centimetre-scale particles—resolved imaging reveals an unexpected surficial diversity. The albedo, texture, particle size and roughness are beyond the spacecraft design specifications. On the basis of our pre-encounter knowledge, we developed a sampling strategy to target 50-metre-diameter patches of loose regolith with grain sizes smaller than two centimetres4. We observe only a small number of apparently hazard-free regions, of the order of 5 to 20 metres in extent, the sampling of which poses a substantial challenge to mission success.

D. S. Lauretta↗
DOE OSTI2019

Selective laser melting of 304L stainless steel: Role of volumetric energy density on the microstructure, texture and mechanical properties

The role of volumetric energy density on the microstructural evolution, texture and mechanical properties of 304L stainless steel parts additively manufactured via selective laser melting process is investigated. 304L is chosen because it is a potential candidate to be used as a matrix in a metal matrix composite with nanoparticles dispersion for energy and high temperature applications. The highest relative density of 99 %±0.5 was achieved using a volumetric energy density of 1400 J/mm 3 . Both XRD analysis and Scheil simulation revealed the presence of a small trace of the delta ferrite phase, due to rapid solidification within the austenitic matrix of 304L. Here, a fine cellular substructure ranged between 0.4–1.8 μm, was detected across different energy density values. At the highest energy density value, a strong texture in the direction of [100] was identified. At lower energy density values, multicomponent texture was found due to high nucleation rate and the existing defects. Yield strength, ultimate tensile strength, and microhardness of samples with a relative density of 99 % were measured to be 540 ± 15 MPa, 660 ± 20 MPa and 254 ± 7 HV, respectively and higher than mechanical properties of conventionally manufactured 304L stainless steel. Heat treatment of the laser melted 304L at 1200 °C for 2 h, resulted in the nucleation of recrystallized equiaxed grains followed by a decrease in microhardness value from 233 ± 3 HV to 208 ± 8 HV due to disappearance of cellular substructure.

304L stainless steel↗
NASA NTRS2006

Mineralogy of nakhlite Martian meteorites: Implications for their relative burial depths

Nakhlites are Martian cumulate rocks mainly composed of augite with variable amounts of olivine and groundmass (mesostasis). Currently seven samples are known: Nakhla (Nak), Governador Valadares (GV), Lafayette (Laf), NWA817, Y000593 (Y), NWA998 and MIL03346 (MIL). All the nakhlites show a similar unbrecciated cumulate texture, and their identical crystallization and exposure ages suggest that they originated from the same igneous body on Mars and were ejected by the same impact event. It is important to study difference of their mineralogy to reconstruct the igneous body from which nakhlites originated. Augite grains in all nakhlites have a nearly identical core composition (En39Fs22Wo39) and have thin Fe-rich rims. These Fe-rich rims are zoned to Ca-poor pyroxene compositions and the degree of chemical zoning varies from one sample to another. NWA998 has the most Mg-rich edge composition. The edge composition becomes more Fe-rich in the order of Laf, Nak/GV, Y and NWA817. Unlike other samples, the Fe-rich edge of MIL augite is zoned to the hedenbergite composition. Olivine grains in all samples except Laf and NWA998 show extensive chemical zoning whose degree is clearly related to the chemical zoning of pyroxenes. MIL and NWA817 have the widest compositional ranges (Fa54-93). Y has a slightly narrower compositional range of Fa58-85. Nak and GV have even narrower ranges (Fa58-72). In contrast to these samples, olivines in Laf and NWA998 are homogeneous (Fa66-67 and Fa61-62, respectively). Such chemical zoning (Fa and Ca) can be used to quantitatively estimate their cooling rates (burial depths) because it was clearly formed by interaction with the intercumulus melt. The obtained burial depths are 1-2 m for NWA817, 4 m for MIL, 7 m for Y, approx.10 m for Nak and GV, and >30 m for Laf and NWA998. This order is clearly related to the degree of pyroxene chemical zoning. The abundance and mineralogy of nakhlite groundmass are also consistent with this order. In Nak, GV and Laf, the groundmass abundance is about 7-8%. Y and NWA998 have a slightly higher abundance (10%), while NWA817 and MIL have much higher abundance (20-24%). The groundmass texture is also related to its abundance. The groundmass of Nak, GV, Laf and Y is mainly composed of feldspar laths. In contrast, NWA817 and MIL have glassy mesostasis without feldspar crystals. In NWA998, feldspar is a large blocky crystal with clear twinning, suggesting that it is even deeper than Laf.

Mikouchi, T.↗
DOE OSTI2021

Microstructure and Mechanical Properties of the AA7075 Tube Fabricated using Shear Assisted Processing and Extrusion (ShAPE)

Shear Assisted Processing and Extrusion (ShAPE) experimental setup and tooling were adopted for extruding thin-walled AA7075 aluminum tube from as-cast non-homogenized billet material in a single run. The mechanical and microstructural characterizations were performed on the extrudate in the as-extruded condition without subsequent heat treating. It was shown that the ShAPE process developed a significantly refined microstructure with uniform and almost equiaxed grain structure on both hoop and axial cross-sections of the extrudate as well as through the thickness of the material. The pole figures and inverse pole figures of the EBSD data showed an strong shear texture development, and it was found out that axial shear is the dominant deformation mechanism in the regions near the inner surface of the tube, while combined axial and torsional shears are the two dominant modes of deformation near the outer surface of the extrudate. As for the mechanical properties, there was an increase of 150% and 73% in the yield and ultimate strengths of the tube produced using ShAPE process, respectively, and a 18% decrease in maximum uniform plastic elongation compared to the conventionally extruded AA7075-O tube.

Shear Assisted Processing and Extrusion, Friction ↗