SEARCH · Engineering Papers

Results for “treatment”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34

All sources NASA NTRS DOE OSTI

NASA NTRS1986

Creep properties of PWC-11 base metal and weldments as affected by heat treatment

In a preliminary study using single specimens for each condition, PWC-11 (a niobium-base alloy with a nominal composition of Nb-1%Zr-0.1%C) was creep tested at 1350 K and 40 MPa. Base metal specimens and specimens with transverse electron beam welds were tested with and without a 1000 hr, 1350 K aging treatment prior to testing. In the annealed condition (1 hr at 1755 K + 2 hr at 1475 K), the base metal exhibited superior creep strength compared to the nonaged condition, reaching 1 percent strain in 3480 hr. A 1000 hr, 1350 K aging treatment prior to creep testing had a severe detrimental effect on creep strength of the base metal and transverse electron beam weldments, reducing the time to attain 1 percent strain by an order of magnitude. Extrapolated temperature compensated creep rates indicate that the present heat of PWC-11 may be four times as creep resistant as similarly tested Nb-1%Zr. The extrapolated stress to achieve 1 percent creep strain in 7 yr at 1350 K is 2.7 MPa for annealed Nb-1%Zr and 12 MPa for annealed and aged PWC-11 base metal with and without a transverse electron beam weld.

Titran, R. H.↗

NASA NTRS1986

Microstructure/mechanical property relationships for various thermal treatments of Al-Cu-Mg-X PM aluminum alloys

The thermal response and aging behavior of three 2XXX-series powder metallurgy aluminum alloys have been investigated, using Rockwell B hardness measurements, optical and electron microscopy, and energy-dispersive chemical analysis, in order to correlate microstructure with measured mechanical properties. Results of the thermal response study indicated that an increased solution heat treatment temperature was effective in resolutionizing large primary constituents in the alloy bearing more copper but had no apparent effect on the microconstituents of the other two. Aging studies conducted at room temperature and at 120, 150, and 180 C for times ranging up to 60 days indicated that classic aging response curves, as determined by hardness measurements, occurred at lower aging temperatures than were previously studied for these alloys, as well as at lower aging temperatures than are commonly used for ingot metallurgy alloys of similar compositions. Microstructural examination and fracture surface analysis of peak-aged tension specimens indicated that the highest tensile strengths are associated with extremely fine and homogeneous distributions of theta-prime or S-prime phases combined with low levels of both large constituent particles and dispersoids. Examination of the results suggest that refined solution heat treatments and lower aging temperatures may be necessary to achieve optimum mechanical properties for these 2XXX series alloys.

Blackburn, L. B.↗

NASA NTRS1986

The response of cobalt-free Udimet 700 type alloy to modified heat treatments

A superalloy based on Udimet 700, in which all of the cobalt was replaced by nickel, was prepared from hot isostatically pressed prealloyed powders. This material was given various heat treatments consisting of partial solutioning and aging in a sequence of four different temperatures. Comparisons were made of microstructures and mechanical properties. Best results were obtained by partially solutioning at 1145 deg C and aging through a sequence of 870, 1030, 650 and 760 deg C. This heat treatment also provided significantly improved properties for wrought material of the same composition. The results suggest that cobalt free Udimet 700 should be considered as a substitute for Udimet 700 with the standard 17 percent cobalt content.

Harf, F. H.↗

NASA NTRS1987

Heat treatment for superalloy

A cobalt-free nickel-base superalloy composed of in weight % 15 Cr-5 Mo-3.5 Ti-4 Al-0.07 (max) C-remainder Ni is given a modified heat treatment. With this heat treatment the cobalt-free alloy achieves certain of the mechanical properties of the corresponding cobalt-containing nickel-base superalloy at 1200 F (650 C). Thus, strategic cobalt can be replaced by nickel in the alloy.

Harf, Fredric H.↗

NASA NTRS1986

Ultrasonic verification of microstructural changes due to heat treatment

Ultrasonic attenuation was measured for polycrystalline samples of nickel and copper with various grain-size distributions produced by heat treatment. Attenuation as a function of frequency was determined for a sample having a known mean grain diameter. Once this function was determined, it could be scaled to determine the mean grain size of other samples of the same material with different mean grain diameters. These results were obtained by using broadband pulse-echo ultrasound in the 25 to 100 MHz frequency range. The results suggest an ultrasonic, nondestructive approach for verifying heat treatment of metals.

Generazio, E. R.↗

NASA NTRS1987

Effect of heat treatment on the fracture behaviour of directionally solidified (gamma/gamma-prime)-alpha alloy

An investigation is conducted into the influence of various heat treatments on the work of fracture and its relation to microstructure for a directionally solidified Ni-33Mo-5.7Al (wt pct) (gamma/gamma-prime)-alpha alloy. The jagged crack propagation observed is due to delamination of the ligaments and associated plastic deformation. Fracture behavior is examined with respect to alloy microstructures and load-deflection curves. The four heat-treatment conditions considered are: (1) as-directionally solidified, (2) solutionized, (3) directionally solidified and thermally cycled, and (4) solutionized and thermally cycled.

Sriramamurthy, A. M.↗

NASA NTRS1989

Acoustic evaluation of the Helmholtz resonator treatment in the NASA Lewis 8- by 6-foot supersonic wind tunnel

The acoustic consequences of sealing the Helmholtz resonators of the NASA Lewis 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT) were experimentally evaluated. This resonator sealing was proposed in order to avoid entrapment of hydrogen during tests of advanced hydrogen-fueled engines. The resonators were designed to absorb energy in the 4- to 20-Hz range; thus, this investigation is primarily concerned with infrasound. Limited internal and external noise measurements were made at tunnel Mach numbers ranging from 0.5 to 2.0. Although the resonators were part of the acoustic treatment installed because of a community noise problem their sealing did not seem to indicate a reoccurrence of the problem would result. Two factors were key to this conclusion: (1) A large bulk treatment muffler downstream of the resonators was able to make up for much of the attenuation originally provided by the resonators, and (2) there was no noise source in the tunnel test section. The previous community noise problem occurred when a large ramjet was tested in an open-loop tunnel configuration. If a propulsion system producing high noise levels at frequencies of less than 10 Hz were tested, the conclusion on community noise would have to be reevaluated.

Heidelberg, Laurence J.↗

NASA NTRS1990

Ozone Treatment For Cooling Towers

Report presents results of study of cooling tower in which water treated with ozone instead of usual chemical agents. Bacteria and scale reduced without pollution and at low cost. Operating and maintenance costs with treatment about 30 percent of those of treatment by other chemicals. Corrosion rates no greater than with other chemicals. Advantage of ozone, even though poisonous, quickly detected by smell in very low concentrations.

Blackwelder, Rick↗

NASA NTRS1990

Heat treatment study of the SiC/Ti-15-3 composite system

The oxidation and aging behaviors of a continuous fiber SiC/Ti-15V-3Cr-3Sn-3Al composite (SiC/Ti-15-3) were investigated. The aging characteristic of the composite were compared with those of the unreinforced Ti-15-3 matrix material, which was processed in the same manner as the composite. Various age hardened conditions of both the unreinforced matrix and the composite were evaluated by using optical microscopy, hardness measurements, and room temperature tensile tests (unreinforced matrix only). The Ti-15-3 material formed a thick surface oxide at temperature at or above 550 C when heat treated in air. The in situ composite matrix was softer than the unreinforced matrix for equivalent aging conditions. Both materials hardened to a maximum, then softened during overaging. The temperature at which peak aging occurred was approx. 450 C for both the in situ composite matrix and the unreinforced matrix. The room temperature elastic modulus and ultimate tensile strength of the unreinforced matrix varied as a function of aging treatment and paralleled the hardness behavior. The modulus and tensile strength showed little response to aging up to temperatures of 300 C; however, these properties increased after aging at 550 C. Aging at temperatures above 550 C resulted in a decrease in the modulus and tensile strength. The failure strain was a function of the precipitation state and of the amount of oxidation resulting from the heat treatment. Aging in air at the higher temperatures (greater than 550 C) caused the formation of a thick oxide layer and reduced the ductility. Aging in vacuum at these temperatures resulted in significantly higher ductilities. Long term exposures at 700 C caused the formation of a large grain boundary alpha-phase which reduced the ductility, even though the specimens were heat treated in vacuum.

Lerch, Bradley A.↗

NASA NTRS1991

Design and performance of duct acoustic treatment

The procedure for designing acoustic treatment panels used to line the walls of aircraft engine ducts and for estimating the resulting suppression of turbofan engine duct noise is discussed. This procedure is intended to be used for estimating noise suppression of existing designs or for designing new acoustic treatment panels and duct configurations to achieve desired suppression levels.

Motsinger, R. E.↗

NASA NTRS1992

Application of the Stogryn-Hirschfelder treatment of weak dimers to planetary atmospheres

The thermodynamics of carbon dioxide dimerization is treated as an example of the evaluation of weak dimer populations in planetary atmospheres (e.g., Mars and Venus). Two approaches considered are the Stogryn-Hirschfelder (1960) treatment using the Lennard-Jones interaction and calculations based on recent quantum chemical data. Several improvements of these treatments are developed. It is indicated that carbon dioxide dimers may be less or more abundant at the surfaces of Mars or Venus, respectively, than is suggested by previous calculations.

Slanina, Zdenek↗

NASA NTRS1992

Enhanced fatigue and retention in ferroelectric thin film memory capacitors by post-top electrode anneal treatment

Thin film ferroelectric capacitors comprising a ferroelectric film sandwiched between electrodes for nonvolatile memory operations are rendered more stable by subjecting the capacitors to an anneal following deposition of the top electrode. The anneal is done so as to form the interface between the ferroelectric film and the top electrode. Heating in an air oven, laser annealing, or electron bombardment may be used to form the interface. Heating in an air oven is done at a temperature at least equal to the crystallization temperature of the ferroelectric film. Where the ferroelectric film comprises lead zirconate titanate, annealing is done at about 550 to 600 C for about 10 to 15 minutes. The formation treatment reduces the magnitude of charge associated with the nonswitching pulse in the thin film ferroelectric capacitors. Reduction of this charge leads to significantly more stable nonvolatile memory operations in both digital and analog memory devices. The formation treatment also reduces the ratio of change of the charge associated with the nonswitching pulse as a function of retention time. These improved memory devices exhibit greater performance in retention and reduced fatigue in memory arrays.

Thakoor, Sarita↗

NASA NTRS1993

Eddy current characterization of magnetic treatment of nickel 200

Eddy current methods have been applied to characterize the effect of magnetic treatments on component service-life extension. Coil impedance measurements were acquired and analyzed on nickel 200 specimens that have been subjected to many mechanical and magnetic engineering processes: annealing, applied strain, magnetic field, shot peening, and magnetic field after peening. Experimental results have demonstrated a functional relationship between coil impedance, resistance and reactance, and specimens subjected to various engineering processes. It has shown that magnetic treatment does induce changes in electromagnetic properties of nickel 200 that then exhibit evidence of stress relief. However, further fundamental studies are necessary for a thorough understanding of the exact mechanism of the magnetic field processing effect on machine-tool service life.

Chern, E. J.↗

NASA NTRS1993

Treatment efficacy of intramuscular promethazine for Space Motion Sickness

Intramuscular promethazine and its efficacy in the treatment of Space Motion Sickness (SMS) were evaluated using standardized questions administered during postflight debriefings to crewmembers immediately after their first Shuttle flight. The comparison showed that 25 percent of crewmembers treated with IM promethazine were 'sick' on flight day 2, compared to 50 percent of crewmembers who did not receive promethazine, 90 percent reported immediate symptom relief as well. Untreated crewmembers typically have slow symptom resolution over 72-96 h, and those treated with oral scopolamine/dextroamphetamine show delayed symptom development. This study suggests that intramuscular promethazine is an effective treatment for SMS and merits continued use and further controlled investigations.

Davis, Jeffrey R.↗

NASA NTRS1988

Conceptual design of a water treatment system to support a manned Mars colony

The initial tasks addressed by the Prairie View A&M University team were the conceptual design of a breathable-air manufacturing system, a means of drilling for underground water, and a method for storing water for future use. Subsequently, the design objective of the team for the 1987-1988 academic year was the conceptual design of an integrated system for the supply of quality water for biological consumption, farming, residential and industrial use. The source of water for these applications is assumed to be artesian or subsurface. The first step of the project was to establish design criteria and major assumptions. The second step of the effort was to generate a block diagram of the expected treatment system and assign tasks to individual students. The list of processes for water purification and wastewater treatment given above suggests that there will be a need for on-site chemicals manufacturing for ion-exchange regeneration and disinfection. The third step of the project was to establish a basis for the design capacity of the system. A total need of 10,000 gal/day was assumed to be required. It was also assumed that 30,000 gallon raw-water intake volume is needed to produce the desired effluent volume.

Source record↗

NASA NTRS1950

Dependence of the elastic strain coefficient of copper on the pre-treatment

The effect of various pre-treatments on the elastic strain coefficient (alpha) (defined as the reciprocal of the modulus of elasticity E) (Epsilon) and on the mechanical hysteresis of copper has been investigated. Variables comprising the pre-treatments were pre-straining by stretching in a tensile testing machine and by drawing through a die, aging at room and elevated temperatures and annealing. The variation of the elastic strain coefficient with test stress was also investigated.

RODS - TENSION↗

NASA NTRS1993

Terrestrial bitumen analogue of orgueil organic material demonstrates high sensitivity to usual HF-HCl treatment

The relationship between the chemical composition and the interlayer spacing (d002) of organic materials (OM's) is known for various terrestrial OM's. We improved this general trend by correlation with corresponding trend of natural solid bitumens (asphaltite-kerite-anthraxolite) up to graphite. Using the improved trend we identified bitumen analogs of carbonaceous chondrite OM's residued after HF-HCl treatment. Our laboratory experiment revealed that these analogs and, hence, structure and chemical composition of carbonaceous chondrite OM's are very sensitive to the HF-HCl treatment. So, usual extraction of OM from carbonaceous chondrites may change significantly structural and chemical composition of extracted OM.

Korochantsev, A. V.↗

NASA NTRS1993

Autogenic-feedback training: A potential treatment for post-flight orthostatic intolerance in aerospace crews

Postflight orthostatic intolerance was identified as a serious biomedical problem associated with long duration exposure to microgravity in space. High priority was given to the development of countermeasures for this disorder which are both effective and practical. A considerable body of clinical research demonstrated that people can be taught to increase their own blood pressure voluntarily and that this is an effective treatment for chronic orthostatic intolerance in paralyzed patients. The present pilot study was designed to examine the feasibility of adding training in control of blood pressure to an existing preflight training program designed to facilitate astronaut adaptation to microgravity. Using an operant conditioning procedure, Autogenic-Feedback Training (AFT), three men and two women participated in four to nine (15-30 training sessions). At the end of training, the average increase in systolic and diastolic pressure, as well as mean arterial pressures that the subjects made, ranged between 20 and 5O mmHg under both supine and 45 deg head-up tilt conditions. These findings suggest that AFT may be a useful alternative treatment or supplement to existing approaches for preventing postflight orthostatic intolerance. Further, the use of operant conditioning methods for training cardiovascular responses may contribute to the general understanding of the mechanisms of orthostatic intolerance.

Cowings, Patricia S.↗