Accession Number : AD0834868

Title :   INVESTIGATIONS TO UNDERSTAND THE DEFORMATION AND STRENGTHENING MECHANISMS OF THE SOLID SOLUTION PHASES OF TITANIUM,

Corporate Author : FRANKLIN INST PHILADELPHIA PA

Personal Author(s) : Jones, R. L. ; Cooke, F. W. ; Conrad, H. ; Banerjee, B. R.

Report Date : FEB 1968

Pagination or Media Count : 98

Abstract : Mechanical properties data are reported for alpha-titanium of four impurity contents and various grain sizes, tested in the temperature range 4.2K to 800K. Dislocation substructures produced by deformation of commercial purity and high purity alpha-titanium at room temperature were examined by transmission electron microscopy and representative examples are presented and discussed. Work hardening behavior is connected with long-range interactions and is modified by both purity and grain size as well as temperature. The effect of impurity content appears to be related to the degree to which dislocations are restricted to their slip planes. Grain size also influences the yield and flow stresses, the relations observed being approximately of the Hall-Tetch type. The effects of grain size are shown to be athermal in nature and are accounted for in terms of work hardening model. Thermal activation analysis is used to show that the behavior reported is in agreement with the concept that the rate controlling process for low temperature deformation is thermally activated dislocation glide on first order prism planes over barriers associated with individual interstitial impurity atoms. The analysis shows that the nature of barriers is the same in all four materials and that the rate controlling process is unaffected by either grain size or plastic strain. (Author)

Descriptors :   (*TITANIUM, METALLOGRAPHY), SOLID SOLUTIONS, MECHANICAL PROPERTIES, DISLOCATIONS, CRYOGENICS, LOW TEMPERATURE, HIGH TEMPERATURE, IMPURITIES, GRAIN SIZE, DEFORMATION, ELECTRON MICROSCOPY, CRYSTAL SUBSTRUCTURE, INTERACTIONS, THERMAL ANALYSIS, RECRYSTALLIZATION, GRAIN STRUCTURES(METALLURGY), HARDENING, NONDESTRUCTIVE TESTING.

Subject Categories : Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE