Correlation of acoustic emission generated during uniform biaxial loading to microstructural sources in 7075-T651 aluminum and 21Cr-6Ni-9Mn stainless steel. Final report

Technical Report · Tue Dec 01 04:00:00 EST 1981

DOI:https://doi.org/10.2172/5683011· OSTI ID:5683011

Leon, E; Mukherjee, A K

This paper reports on the effect on acoustic emission (AE) of uniform biaxial loading of a thin-walled tube designed by Hamstad, Patterson and Mukherjee. The AE generated during biaxial loading of 7075-T651 aluminum and 21Cr-6Ni-9Mn stainless steel had several anomalous features relative to tensile generated AE. The biaxial AE data was of a much higher level and peaked at a lower strain than the uniaxial AE response. A particle cracking model was proposed in which inclusions with the largest projected surface area perpendicular to the principal axis of applied loading will crack before smaller inclusions, and the resulting energy released per AE will be proportional to the crack surface area. The inclusion contents were studied with respect to size, shape, density, hardness, and fracture/decohesion behavior. The inclusions in both 7075-T651 and 21-6-9 display the preferred cracking orientation predicted in the Hamstad, et al. model and are shown to be associated with the generated AE. However, other factors appear to contribute to the total AE responses. There is evidence that for 7075-T651 subjected to biaxial loading, a grain boundary-related mechanism becomes a significant source of AE in the latter stages of strain hardening. Also, for both materials, the complex applied load during biaxial loading appears to amplify the level of AE.

• Research Organization: Lawrence Livermore National Lab., CA (USA); California Univ., Davis (USA). Dept. of Mechanical Engineering
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5683011
• Report Number(s): UCRL-15421; ON: DE82006783
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
42 ENGINEERING
420500 -- Engineering-- Materials Testing
ACOUSTIC EMISSION TESTING
ACOUSTIC TESTING
ALLOYS
ALUMINIUM
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
CRACK PROPAGATION
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
ELEMENTS
GRAIN BOUNDARIES
INCLUSIONS
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MATERIALS TESTING
METALS
MICROSCOPY
MICROSTRUCTURE
NICKEL ALLOYS
NONDESTRUCTIVE TESTING
OPTICAL MICROSCOPY
SCANNING ELECTRON MICROSCOPY
STAINLESS STEEL-21-6-9
STAINLESS STEELS
STEELS
TESTING