Engineering topics

Hendrix, J. C.

Publications and source records attributed to Hendrix, J. C..

7 records

NASA NTRS1987

Directional Solidification of Nodular Cast Iron

Cerium enhances formation of graphite nodules. Preliminary experiments in directional solidification of cast iron shows quantitative correlation of graphite microstructure with growth rate and thermal gradient, with sufficient spheroidizing element to form spheroidal graphite under proper thermal conditions. Experimental approach enables use of directional solidification to study solidification of spheriodal-graphite cast iron in low gravity. Possible to form new structural materials from nodular cast iron.

Curreri, P. A.↗

NASA NTRS1987

Directional solidification of flake and spheroidal graphite cast iron in low and normal gravity environment

A NASA KC-135 research aircraft, flying repeated low-g trajectories that yield 20-30 sec of 0.1-0.001 g microgravity, has been used to study microgravity solidification's elimination of sedimentation and convection (with formation of unique and advantageous microstructures) for the case of eutectic-composition cast irons. The solidification interface of hypereutectic flake and spheroidal graphite cast irons has been slowly advanced through a 4 mm-diameter rod sample. Sample solidification rates have been correlated with accelerometer data, while independently controlling thermal gradients and solidification rates.

Hendrix, J. C.↗

NASA NTRS1986

Low-Gravity Alloy Studies on Aircraft

Controlled solidification continued through many dives. Since each dive gives 20 to 30 seconds in which gravity is 0.001 to 0.1 its normal value, and aircraft may make about ten low-gravity maneuvers in mission, technique allows substantial time to conduct a low-gravity experiment. In directional solidification, liquid/solid interface advanced slowly through rod of sample alloy. Solidification continues during several aircraft maneuvers. Known solidification rate of sample correlated with accelerometer data to find gravity value during solidification for any point in sample. Thermal gradient and solidification rate controlled independently.

Curreri, P. A.↗

NASA NTRS1986

Cast Iron With High Carbon Content

Method proposed for solidifying high-carbon cast iron without carbon particles segregating at upper surface. Solidification carried out in low gravity, for example on airplane flying free-fall parabolic trajectory. Many different microstructures obtained by proposed technique, and percentage by weight of carbon retained in melt much higher than at present.

Curreri, P. A.↗

NASA NTRS1986

Solidifying Cast Iron in Low Gravity

Report describes study of solidification of cast iron in low and normal gravity. Because flotation, sedimentation, and convection suppressed, alloys that solidify at nearly zero gravity have unusual and potentially useful characteristics. Study conducted in airplane that repeatedly flew along parabolic trajectories. Appears iron/carbon alloys made at low gravity have greater carbon content (as high as 5 to 10 percent) than those made of Earth gravity because carbon particles do not float to top of melt.

Hendrix, J. C.↗

NASA NTRS1984

Directional solidification of flake and nodular cast iron during KC-135 low-g maneuvers

Alloys solidified in a low-gravity environment can, due to the elimination of sedimentation and convection, form unique and often desirable microstructures. One method of studying the effects of low-gravity (low-g) on alloy solidification was the use of the NASA KC-135 aircraft flying repetitive low-g maneuvers. Each maneuver gives from 20 to 30 seconds of low-g which is between about 0.1 and 0.001 gravity. A directional solidification furnace was used to study the behavior of off eutectic composition case irons in a low-g environment. The solidification interface of hypereutectic flake and spheroidal graphite case irons was slowly advanced through a rod sample, 5 mm in diameter. Controlled solidification was continued through a number of aircraft parabolas. The known solidification rate of the sample was then correlated with accelerometer data to determine the gravity level during solidification for any location of the sample. The thermal gradient and solidification rate were controlled independently. Samples run on the KC-135 aircraft exhibited bands of coarser graphite or of larger nodules usually corresponding to the regions solidified under low-g. Samples containing high phosphorous (used in order to determine the eutectic cell) exhibited larger eutectic cells in the low-g zone, followed by a band of coarser graphite.

Curreri, P. A.↗

NASA NTRS1983

Preliminary science report on the directional solidification of hypereutectic cast iron during KC-135 low-G maneuvers

An ADSS-P directional solidification furnace was reconfigured for operation on the KC-135 low-g aircraft. The system offers many advantages over quench ingot methods for study of the effects of sedimentation and convection on alloy formation. The directional sodification furnace system was first flown during the September 1982 series of flights. The microstructure of the hypereutectic cast iron sample solidified on one of these flights suggests a low-g effect on graphite morphology. Further experiments are needed to ascertain that this effect is due to low-gravity and to deduce which of the possible mechanisms is responsible for it.

Curreri, P. A.↗