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Investigation of the parameters influencing the microstructure of hot-pressed boron carbide

Description: An investigation was conducted to determine the influence of various parameters on the microstructure of hot-pressed boron carbide compacts. It was determined that a critical temperature (approximately 2200/sup 0/C) was necessary to suppress exaggerated grain growth, and that exaggerated growth was also enhanced at higher pressures within the pressure range investigated. Microhardness examinations and twin density analyses were also performed, both of which demonstrated a primary dependence on … more
Date: November 1, 1975
Creator: Munir, Z. A. & Veerkamp, G. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effect of point defects on mechanical properties of metals. Progress report, January 1, 1975--December 31, 1975

Description: Results of research activities are presented on electron irradiation softening in pure Fe, effects of impurities on electron irradiation softening, electron microscopic investigation of electron irradiation softening, surface film softening, and dislocation motion. (JRD)
Date: December 1, 1975
Creator: Meshii, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Irradiation Softening in Pure Iron Single Crystals

Description: The characteristics of irradiation softening in Fe were studied. Results show that irradiation softening effect can be explained by the intrinsic mechanism, namely, the interaction of screw dislocations with randomly dispersed interstitials. At least some of the solid solution softening phenomena observed in alloys can be explained by the same mechanism. However, the alloying may be accompanied by an additional effect such as solute segregation to dislocations which may also strongly affect the… more
Date: January 1, 1975
Creator: Meshii, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Positron lifetime measurements as a non-destructive technique to monitor fatigue damage

Description: In the fatigue cycling of initially hard copper, self consistent positron lifetime and x-ray particle size measurements followed the softening process and revealed a new feature which may be the final development of microvoids before fracture. In the cyclic fatigue of initially soft 4340 steel closely spaced concurrent measurements of these parameters are now in progress. For initially hard 4340 steel fatigue softening was revealed with a large positron lifetime decrease. In hydrogen embrittlem… more
Date: September 1, 1975
Creator: Byrne, J.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Cluster carburizing. Progress report, June 1, 1975--May 31, 1976. [Ta--Hf]

Description: The Ta--Hf phase diagram was found to be sensitive to carbon content, even at levels low enough to prevent carbide formation. The ..beta../..cap alpha.. solvus at 1200/sup 0/C went from 27 to 7 percent Hf as the soluble carbon concentration increased. This effect was seen in aged and carburized samples. Just below the carbide-containing subscale, the dissolved C concentration was greater than in the bulk sample and correspondingly the amount of ..cap alpha.. phase there was greater. The hardnes… more
Date: June 1, 1975
Creator: Morral, J. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ductile to brittle transition of U--0.75 wt% Ti penetrator cores

Description: V-notch Charpy impact specimens were machined from U--0.75 wt percent Ti penetrator cores supplied by the Air Force Armament Laboratory. The response of these specimens to impact loads at various temperatures was measured. The data indicated that the impact energy required to cause fracture was a function of temperature and appeared to be insensitive to microstructural and hardness variations. All tests from --54 to 300$sup 0$C indicated a brittle condition with data fitting the impact energy =… more
Date: August 1, 1975
Creator: Jones, Thomas I. & Sandstrom, Donald J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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