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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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107 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Friction-Stir-Welded and Spin-Formed End Domes for Cryogenic Tanks

Manufacturing of single-piece end domes for cryogenic tanks employing spin forming of tailored, friction-stir-welded blanks of Al-Li alloy 2195 plate offers cost and reliability benefits. The introduction of plastic deformation into a friction stir weld is a unique feature of the proposed manufacturing route. This investigation addressed abnormal grain growth [AGG] within the friction stir weldments during postfabrication processing of a prototype dome. The phenomenon of AGG was observed during the solution heat treatment [SHT] phase of T8 tempering and is a major concern for meeting specifications. Such abrupt microstructural transitions can be detrimental to notch-sensitive mechanical properties, such as ductility and/or fracture toughness. If the issue of AGG cannot be resolved, then the acceptance of this approach as a viable manufacturing route may be in jeopardy. The innovative approach adopted in this investigation was the insertion of a stand-alone, Intermediate Annealing Treatment [IAT] between the spin forming and T8 processing operations. A simple, recovery annealing step was deemed to be the most readily-scalable solution when fabricating thin-walled, ellipsoidal domes. The research effort culminated in the development of an effective IAT, which resulted in a significant decrease in AGG following SHT. The processing philosophy adopted in designing the IAT is outlined and the microstructural reasons for success are discussed. The analytical results presented are consistent with promoting continuous grain growth during the IAT, thereby suppressing AGG during the SHT.

Hales, S. J.↗
NASA NTRS2012

Correlation of Fracture Behavior With Microstructure in Friction Stir Welded, and Spin Formed AI-Li 2195 Domes

Single-piece, spin-formed domes manufactured from friction stir welded (FSW) plates of Al-Li alloy 2195 have the potential to reduce the cost of fabricating cryogenic propellant tanks. Mechanical properties in the completed domes can be related directly to the final material condition and the microstructures developed. However, these new fabrication techniques have resulted in unexpected material challenges, such as abnormal grain growth in the weld nugget and the propensity for fracture in the adjacent thermo-mechanically affected zone (TMAZ). In this study, the microstructure and texture transformations within the TMAZ are related to fracture location in the vicinity of the weldment. The texture variations in the TMAZ are caused primarily by the varying amounts of shear deformation introduced during the FSW process. Grain morphology and microtexture characteristics are examined as a function of location in the TMAZ via electron backscatter diffraction (EBSD). A strong correlation between fracture location and the presence of texture banding in the TMAZ is observed. The fracture path tends to follow a distinct region of low Taylor Factor (TF) grains.

Tayon, Wesley A.↗
NASA NTRS2013

Structures and Design Phase I Summary for the NASA Composite Cryotank Technology Demonstration Project

A description of the Phase I structures and design work of the Composite Cryotank Technology Demonstration (CCTD) Project is in this paper. The goal of the CCTD Project in the Game Changing Development (GCD) Program is to design and build a composite liquid-hydrogen cryogenic tank that can save 30% in weight and 25% in cost compared to state-of-the-art aluminum metallic cryogenic tank technology when the wetted composite skin wall is at an allowable strain of 5000 in/in. Three Industry teams developed composite cryogenic tank concepts that are compared for weight to an aluminum-lithium (Al-Li) cryogenic tank designed by NASA in Phase I of the CCTD Project. The requirements used to design all of the cryogenic tanks in Phase I will be discussed and the resulting designs, analyses, and weight of the concepts developed by NASA and Industry will be reviewed and compared.

Johnson, Ted↗
NASA NTRS2015

Buckling Test Results from the 8-Foot-Diameter Orthogrid-Stiffened Cylinder Test Article TA01

Results from the testing of cylinder test article SBKF-P2-CYLTA01 (referred to herein as TA01) are presented. The testing was conducted at the Marshall Space Flight Center (MSFC), November 19‒21, 2008, in support of the Shell Buckling Knockdown Factor (SBKF) Project.i The test was used to verify the performance of a newly constructed buckling test facility at MSFC and to verify the test article design and analysis approach used by the SBKF project researchers. TA01 is an 8-foot-diameter (96-inches), 78.0-inch long, aluminum-lithium (Al-Li), orthogrid-stiffened cylindrical shell similar to those used in current state-of-the-art launch vehicle structures and was designed to exhibit global buckling when subjected to compression loads. Five different load sequences were applied to TA01 during testing and included four sub-critical load sequences, i.e., loading conditions that did not cause buckling or material failure, and one final load sequence to buckling and collapse. The sub-critical load sequences consisted of either uniform axial compression loading or combined axial compression and bending and the final load sequence subjected TA01 to uniform axial compression. Traditional displacement transducers and strain gages were used to monitor the test article response at nearly 300 locations and an advanced digital image correlation system was used to obtain low-speed and high-speed full-field displacement measurements of the outer surface of the test article. Overall, the test facility and test article performed as designed. In particular, the test facility successfully applied all desired load combinations to the test article and was able to test safely into the postbuckling range of loading, and the test article failed by global buckling. In addition, the test results correlated well with initial pretest predictions.

Hilburger, Mark W.↗
NASA NTRS2015

Aluminum 2195 T8 Gore Development for Space Launch System Core and Upper Stage

Gores are pie-shaped panels that are welded together to form the dome ends of rocket fuel tanks as shown in figure 1. Replacing aluminum alloy 2219 with aluminum (Al)-lithium (Li) alloy 2195 as the Space Launch System (SLS) cryogenic tank material would save enormous amounts of weight. In fact, it has been calculated that simply replacing Al 2219 gores with Al 2195 gores on the SLS core stage domes could save approximately 3,800 pound-mass. This is because the Al-Li 2195 alloy exhibits both higher mechanical properties and lower density than the SLS baseline Al 2219 alloy. Indeed, the known advantages of Al 2195 led to its use as a replacement for Al 2219 in the shuttle external tank program. The required thicknesses of Al 2195 gores for either SLS core stage tanks or upper stage tanks will depend on the specific design configurations. The required thicknesses or widths may exceed the current experience base in the manufacture of such gores by the stretch-forming process. Accordingly, the primary objective of this project was to enhance the formability of Al 2195 by optimizing the heat treatment and stretch-forming process for gore thicknesses up to 0.75 inches, which envelop the maximum expected gore thicknesses for SLS tank configurations.

Volz, Martin↗
NASA NTRS2017

Buckling Test Results and Preliminary Test and Analysis Correlation from the 8-Foot-Diameter Orthogrid-Stiffened Cylinder Test Article TA02

Results from the testing of cylinder test article SBKF-P2-CYL-TA02 (referred to herein as TA02) are presented. TA02 is an 8-foot-diameter (96-inches), 78.0-inch-long, aluminum-lithium (Al-Li), orthogrid-stiffened cylindrical shell similar to those used in current state-of-the-art launch-vehicle structures and was designed to exhibit global buckling when subjected to combined compression and bending loads. The testing was conducted at the Marshall Space Flight Center (MSFC), February 3-6, 2009, in support of the Shell Buckling Knockdown Factor Project (SBKF). The test was used to verify the performance of a newly constructed buckling test facility at MSFC and to verify the test article design and analysis approach used by the SBKF researchers.

Hilburger, Mark W.↗
NASA NTRS2019

Automated Grain Yield Behavior Classification

A method for classifying grain stress evolution behaviors using unsupervised learning techniques is presented. The method is applied to analyze grain stress histories measured in-situ using high-energy X-ray diffraction microscopy (HEDM) from the aluminum-lithium alloy Al-Li 2099 at the elastic-plastic transition (yield). The unsupervised learning process automatically classified the grain stress histories into four groups: major softening, no work-hardening or softening, moderate work-hardening, and major work-hardening. The orientation and spatial dependence of these four groups are discussed. In addition, the generality of the classification process to other samples is explored.

Pagan, Darren C↗
NASA NTRSDate not supplied

Parametric Studies of Human Mars Entry, Descent, and Landing Systems

This paper will present a parametric analysis for entry, descent, and landing (EDL) concepts, enabling rapid systems assessment and tradespace exploration. The entry system uses a hypersonic inflatable aerodynamic decelerator (HIAD) technology. The baseline system includes elements for Mars aerocapture (AC) and EDL segments of the mission. The mission concept of operations (ConOps) begins at Mars arrival in a polar inclination. After performing an aerocapture (AC) maneuver into a pre-defined Mars parking orbit, the AC HIAD is jettisoned. The rest of thevehicle stays in the parking orbit for up to one year. The EDL sequence starts with a deorbit burn at the apoapsis of the parking orbit. After hypersonic entry with the EDL HIAD, the entry system uses a supersonic retropropulsion maneuver to slow the vehicle for the descent and landing segments of the mission. The vehicle will maintain a constant velocity of 2.5 m/s for 5 seconds prior to landing.The system includes a Mars Ascent Vehicle (MAV), Mars Descent Module (MDM), and two HIADs. The MDM includes a primary structure, tanks, engines, and radiators. The primary structure is an aluminum-lithium (Al-Li)cruciform design similar to the structural design of the Apollo Lunar Module. The cruciform planform layout results in four outer bays, with adequate volume in the corners between outer bays to package four landing gears. The central bay is reserved for packaging the MAV and the recessed MAV engines. Two of the outer bays accommodate main propellant tanks, with one LOX and one CH4 tank in each bay. The two remaining outer bays each house four rocket engine systems and associated support structure. Each HIAD comprises an inflatable structure, flexible thermal protection system, gas, and gas generators. The HIAD design used in this study is a stacked-toroid concept with pairing loop straps and radial/chevron straps. The baseline system lands a 20-t payload on the Mars surface. It is assumed the vehicle arrives at 6.2 km/s relative velocity at 90° inclination and is captured to a 1-Sol parking orbit.The baseline design includes many assumptions such as margins, arrival state, ConOps options, parking orbit, physical dimensions, propellant options, and technology concepts. The impact of these parameters are quantified through systems-level sensitivity analyses, which capture the global impact—not at a component level—but at the systems level. The systems-level sensitivities expose major design drivers and importance of each assumption for a design.Through tradespace exploration, a wide range of systems parameters are examined and compared for several feasible design options. Studies have been completed for the following input parameters: payload mass, propellant options, AC/EDL ballistic coefficient, lander thrust to weight ratio (T/W) (surrogate for the maximum EDL g’s),engine specific impulse (Isp), parking orbit, and inclination.The final paper will present and discuss the parametric approach used in the study. It will also include the results of recent systems analyses, sensitivity analyses, and tradespace exploration

Jamshid Samareh↗
DOE OSTI2022

Origin of strain softening in a nanograined Al alloy

Here, one-step and multi-step nanoindentation experiments were conducted to investigate the mechanical response of an Al-Mg-Li alloy. Opposite to the strain hardening effect observed in the coarse-grained (CG) alloy, the nanograined (NG) alloy exhibits strain softening. Compared with multi-step nanoindentation experiments, the ultralow dislocation density and the grain boundary (GB) segregation promote a higher stress level during one-step nanoindentation experiments. Residual perfect dislocations induced by a previous loading and unloading during multi-step nanoindentation experiments lower the stress required for further plastic deformation. In addition, the storage of partial dislocations also serves to render plastic flow to commence at lower stresses. This work provides new insights for the fabrication and property optimization of NG alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiAl3 by Materials Project

Al3Li is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Li is bonded to twelve equivalent Al atoms to form LiAl12 cuboctahedra that share corners with twelve equivalent LiAl12 cuboctahedra, edges with twenty-four equivalent AlLi4Al8 cuboctahedra, faces with six equivalent LiAl12 cuboctahedra, and faces with twelve equivalent AlLi4Al8 cuboctahedra. All Li–Al bond lengths are 2.85 Å. Al is bonded to four equivalent Li and eight equivalent Al atoms to form distorted AlLi4Al8 cuboctahedra that share corners with twelve equivalent AlLi4Al8 cuboctahedra, edges with eight equivalent LiAl12 cuboctahedra, edges with sixteen equivalent AlLi4Al8 cuboctahedra, faces with four equivalent LiAl12 cuboctahedra, and faces with fourteen equivalent AlLi4Al8 cuboctahedra. All Al–Al bond lengths are 2.85 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li3Al2 by Materials Project

Al2Li3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded in a 4-coordinate geometry to four equivalent Al atoms. There are three shorter (2.73 Å) and one longer (2.90 Å) Li–Al bond lengths. In the second Li site, Li is bonded in a distorted linear geometry to two equivalent Al atoms. Both Li–Al bond lengths are 2.81 Å. Al is bonded in a 8-coordinate geometry to five Li atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li9Al4 by Materials Project

Al4Li9 is zeta silver zinc-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are five inequivalent Li sites. In the first Li site, Li is bonded in a 2-coordinate geometry to two Al atoms. There are one shorter (2.79 Å) and one longer (2.83 Å) Li–Al bond lengths. In the second Li site, Li is bonded in a 4-coordinate geometry to four Al atoms. There are a spread of Li–Al bond distances ranging from 2.77–2.92 Å. In the third Li site, Li is bonded in a 2-coordinate geometry to two equivalent Al atoms. There are one shorter (2.76 Å) and one longer (2.91 Å) Li–Al bond lengths. In the fourth Li site, Li is bonded in a distorted linear geometry to two equivalent Al atoms. Both Li–Al bond lengths are 2.75 Å. In the fifth Li site, Li is bonded in a 3-coordinate geometry to three Al atoms. There are two shorter (2.71 Å) and one longer (2.85 Å) Li–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 8-coordinate geometry to six Li atoms. In the second Al site, Al is bonded in a 9-coordinate geometry to six Li atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li3Al by Materials Project

Li3Al is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded to eight Li and four equivalent Al atoms to form distorted LiLi8Al4 cuboctahedra that share corners with twelve equivalent LiLi8Al4 cuboctahedra, edges with eight equivalent LiLi8Al4 cuboctahedra, edges with eight equivalent AlLi12 cuboctahedra, faces with four equivalent AlLi12 cuboctahedra, and faces with ten equivalent LiLi8Al4 cuboctahedra. There are four shorter (2.77 Å) and four longer (2.94 Å) Li–Li bond lengths. All Li–Al bond lengths are 2.94 Å. In the second Li site, Li is bonded in a square co-planar geometry to eight equivalent Li and four equivalent Al atoms. All Li–Al bond lengths are 2.77 Å. Al is bonded to twelve Li atoms to form AlLi12 cuboctahedra that share corners with four equivalent AlLi12 cuboctahedra, edges with eight equivalent AlLi12 cuboctahedra, edges with sixteen equivalent LiLi8Al4 cuboctahedra, faces with four equivalent AlLi12 cuboctahedra, and faces with eight equivalent LiLi8Al4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiAl3 by Materials Project

Al3Li is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Li is bonded to twelve Al atoms to form LiAl12 cuboctahedra that share corners with four equivalent LiAl12 cuboctahedra, edges with eight equivalent LiAl12 cuboctahedra, edges with sixteen equivalent AlLi4Al8 cuboctahedra, faces with four equivalent LiAl12 cuboctahedra, and faces with eight equivalent AlLi4Al8 cuboctahedra. There are four shorter (2.83 Å) and eight longer (2.86 Å) Li–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Li and eight Al atoms to form distorted AlLi4Al8 cuboctahedra that share corners with twelve equivalent AlLi4Al8 cuboctahedra, edges with eight equivalent LiAl12 cuboctahedra, edges with eight equivalent AlLi4Al8 cuboctahedra, faces with four equivalent LiAl12 cuboctahedra, and faces with ten equivalent AlLi4Al8 cuboctahedra. There are four shorter (2.83 Å) and four longer (2.86 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a distorted square co-planar geometry to four equivalent Li and eight equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li2Al by Materials Project

Li2Al crystallizes in the orthorhombic Cmcm space group. The structure is two-dimensional and consists of two Li2Al sheets oriented in the (0, 1, 0) direction. there are two inequivalent Li sites. In the first Li site, Li is bonded in a 4-coordinate geometry to four equivalent Al atoms. There are two shorter (2.73 Å) and two longer (2.89 Å) Li–Al bond lengths. In the second Li site, Li is bonded in a 2-coordinate geometry to two equivalent Al atoms. Both Li–Al bond lengths are 2.81 Å. Al is bonded in a 9-coordinate geometry to six Li atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiAl by Materials Project

LiAl crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Li is bonded in a 11-coordinate geometry to four equivalent Li and seven Al atoms. There are one shorter (2.86 Å) and three longer (2.95 Å) Li–Li bond lengths. There are one shorter (2.87 Å) and six longer (2.95 Å) Li–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 9-coordinate geometry to six equivalent Li and three equivalent Al atoms. All Al–Al bond lengths are 2.58 Å. In the second Al site, Al is bonded in a 11-coordinate geometry to eight equivalent Li and three equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiAl by Materials Project

LiAl crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. there are three inequivalent Li sites. In the first Li site, Li is bonded to four equivalent Al atoms to form distorted edge-sharing LiAl4 tetrahedra. There are two shorter (2.85 Å) and two longer (2.88 Å) Li–Al bond lengths. In the second Li site, Li is bonded in a 6-coordinate geometry to four Al atoms. There are two shorter (2.79 Å) and two longer (2.81 Å) Li–Al bond lengths. In the third Li site, Li is bonded in a 6-coordinate geometry to six Al atoms. There are a spread of Li–Al bond distances ranging from 2.77–2.98 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 9-coordinate geometry to four Li and five Al atoms. There are a spread of Al–Al bond distances ranging from 2.55–2.70 Å. In the second Al site, Al is bonded in a 5-coordinate geometry to five Li and two equivalent Al atoms.

36 MATERIALS SCIENCE↗