THE THEORY OF MICROTOME SECTIONING WITH AN INFINITELY SHARP CUTTING EDGE
Abstract
A variety of metallurgical and other specimens sectioned on a diamond knife ultra microtome were studied by means of light and electron microscope techniques in an investigation of the mechanisms involved in the machining of metals. It was observed (1) that, when elastic properties were maintained under the highest strains applied during cutting, the sections were not deformed, and (2) that for plastically deforming materials the simple plastic shear may be accompanied by plastic shear on another system in the relief of compressive stresses, causing curvature of the section. A model for this composite stress-relieving mechanism is described. Factors determing the propagation of slip in ductile metals may cause either homogeneous shear with successive slip planes activated or a discrete step slip pattern. Section formation in brittle materials or under conditions with knife edge defects occurs as a series of fractures in the plane of maximum shear stress. Special apparatus was designed to facilitate crystal preorientation for transmission electron microscopy and electron diffraction and replication studies.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 28, 1961
- Accession Number
- AD0257950
Entities
People
- Alyssa Brown
- R. Phillips