Accession Number : ADA189745

Title :   The Effective Fracture Toughness of Aluminum at Rapid Heating Rates.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Nichols, Joseph W

PDF Url : ADA189745

Report Date : Dec 1987

Pagination or Media Count : 102

Abstract : The fracture of aluminum plates, at high temperatures and at rapid heating rates, was investigated using 6061 T-6 aluminum as the test material. Three heating rates were tried low (15 C/sec), medium (150 C/sec), and high (1500 C/sec). Rapid heating and room temperature tensile tests were performed to characterize the material as a function of temperature. Single edge notched specimen and center cracked panels were fabricated for use in fracture tests. A modified linear elastic fracture toughness, called the effective fracture toughness was used to quantify the relationship between fracture toughness and temperature. The Kc was found to decrease as temperatures increased in the same manner as the strength. Heating rate, at least in the range tested, had little effect on either the strength or the fracture toughness. Further, it was found that the fracture behavior of 6061 T-6 aluminum under the tested conditions can be related to net-section yielding. A ductile Fracture model was found to be useful in relating the critical crack size to critical stress. The test data from the present study showed good agreement with this model. Keywords: Fracture toughness, Temperature effects, Rapid heating, Laser effects, Mechanical properties.

Descriptors :   *ALUMINUM, *ALUMINUM ALLOYS, DUCTILITY, ELASTIC PROPERTIES, EXPERIMENTAL DATA, FRACTURE(MECHANICS), HIGH TEMPERATURE, LASER BEAMS, MECHANICAL PROPERTIES, METAL PLATES, PANELS, RADIATION EFFECTS, STRESSES, TENSILE PROPERTIES, TEST AND EVALUATION, TEST METHODS, TOUGHNESS, CRACK PROPAGATION, AEROSPACE CRAFT, PLASTIC DEFORMATION

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE