Accession Number : AD0475734

Title :   FRACTURE OF METALS DURING DEFORMATION PROCESSING UNDER CONDITIONS OF HOT WORKING.

Descriptive Note : Final rept.,

Corporate Author : DREXEL INST OF TECH PHILADELPHIA PA DEPT OF METALLURGICAL ENGINEERING

Personal Author(s) : Dieter, G. E. ; Mullin, J. V. ; Shapiro, E.

Report Date : 30 NOV 1965

Pagination or Media Count : 48

Abstract : The objective of this research is the study of the fracture of metals under conditions of stress, strain, strain rate, and temperature that are representative of hot working deformation processing operations. These experimental conditions are achieved with an instrumented hot torsion test which is modified so that axial stress can be superimposed on the torsional shearing stresses. Torsion tests on Inconel 600 from 800 to 2000 F revealed a ductility minimum at 1400 F. The ductility minimum corresponds to a temperature at which shear deformation is localized to a narrow region. Below this temperature shear deformation is spread throughout the test section. Above 1400 F the metal recrystallizes during the short time of the test. Fracture initiates at grain boundaries and triple points and propagates by a link-up of these voids in a transgranular fashion. Axial tensile load accentuates the void formation. The superposition of a compressive axial stress on the torsional shearing stress produces an eight to ten fold increase in the total strain to fracture. Metallographic evidence of non-propagating cracks leads to the belief that crack propagation is difficult under these conditions. (Author)

Descriptors :   *FRACTURE(MECHANICS)), (*NICKEL ALLOYS, (*DEFORMATION, METALS), HOT WORKING, SHEAR STRESSES, PLASTICS, STRAIN GAGES, DUCTILITY, STRAIN(MECHANICS), TORSION, LOADS(FORCES), INSTRUMENTATION, DYNAMOMETERS, TEMPERATURE, TEST METHODS, HARDENING, ROLLING(METALLURGY), FRACTOGRAPHY, TENSILE PROPERTIES, GRAIN BOUNDARIES, ELECTRON MICROSCOPY, PROCESSING.

Subject Categories : Metallurgy and Metallography
      Fabrication Metallurgy
      Plastics

Distribution Statement : APPROVED FOR PUBLIC RELEASE