STUDY OF MICRODISTRIBUTION OF INTERSTITIAL ELEMENTS IN TITANIUM BY INTERNAL FRICTION TECHNIQUES. Period covered: March 1, 1956 to February 28, 1957

Technical Report · Thu Aug 01 00:00:00 EDT 1957

OSTI ID:4313468

Gupta, D; Weinig, S

S>An investigation of the microdistribution of interstitial elements in Ti and Ti binary alloys end its effect on the mechanical properties was initiated. The experimental techniques which were utilized during this period were internal friction measurements and ''hard'' tensile testing. A study of the solute atom- dislocation interaction of Ti-O alloys was performed. It was foumd that the behavior of the phenomenon was in accord with the relatlonship C = Coexp (V/KT). The interaction energy between an O atom and a dislocation was calculated to be 0.015 ev. The O content required to saturate the dislocatlons was found to be approximately 1.5%. It was also observed that the transit tion from ductile to brittle behavior occurred at the same composition. It was suggested that the transition phenomenon was due to the adsorption of O atoms at the dislocations. In view of this suggestion it was possible to predict the proper treatment to shift the onset of the embrittling effect to higher 0 contents. This was demonstrated experimentally and it was possible to increase the ductility of Ti-O alloys. It was demonstrated that an interstitial stress relaxation phenomenon could be observed in ''superpurity'' Ti. The development of the interstitial peak in alpha Ti is shown to be directly related to the atomic size of the substitutional element in solutlon with the O. The greater the difference in size factor between the solute and the Ti atom, the greater the enhancement of the ''interstitial'' peak. It is suggested that the mechanism whereby the substitutional solute atoms enhance the appearance of the interstital peak is as follows: The out-of-size substitational atom causes a localized distortion of the lattice which effectively destroys the isotropic nature of the octahedral interstitial sites. Hence, one site becomes energetically favorable to another upon the application of an external stress. This causes a stress-induced interstitial relaxation phenomenon which is manifested by the appearance of an internal friction peak. (auth)

• Research Organization: New York Univ., New York. Coll. of Engineering
• DOE Contract Number: AF33(616)-3393
• NSA Number: NSA-12-004201
• OSTI ID: 4313468
• Report Number(s): WADC-TR-57-420; AD-142145
• Resource Relation: Other Information: Project title: METALLIC MATERIALS. Task title: TITANIUM METAL AND ALLOYS. Orig. Receipt Date: 31-DEC-58
• Country of Publication: United States
• Language: English

Related Subjects

MINERALOGY, METALLURGY, AND CERAMICS
ALLOTROPY
ATOMIC MODELS
ATOMS
BRITTLENESS
DEFECTS
DEFORMATION
DISTRIBUTION
DUCTILITY
FRICTION
IMPURITIES
LATTICES
MATERIALS TESTING
MEASURED VALUES
MECHANICAL PROPERTIES
OXYGEN
QUANTITY RATIO
REACTION KINETICS
SOLUTIONS
STRESSES
TENSILE PROPERTIES
TITANIUM
TITANIUM ALLOYS
TITANIUM OXIDES