Accession Number : AD0815909

Title :   EFFECT OF SPECIMEN TYPE AND CRACK ORIENTATION ON FRACTURE TOUGHNESS.

Descriptive Note : Technical rept. Mar 64-Dec 66,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH

Personal Author(s) : Davis, Sidney O. ; Tupper, Nathan G. ; Niemi, Roger M.

Report Date : MAR 1967

Pagination or Media Count : 50

Abstract : The effect of specimen type on the room temperature plane strain fracture toughness of three aluminum alloys: 7079-T6, 7075-T6, and 7001-T75, is presented. The difference in K sub Ic as evaluated with center notch, single edge notch, slow bend, surface flaw and wedge opening loading specimens is discussed. The orientation of the crack plane and crack propagation direction with respect to the working direction, or grain orientation, of the alloys is considered. The possible influence of crack plane and propagation direction on the resulting plane strain fracture toughness value is discussed. The surface flaw specimens seem to yield the highest K sub Ic value followed by slow bend, single edge notch and center notch specimens. The slow bend and surface flaw specimens were the most sensitive to material variability. Differences in orientation between crack propagation direction and material grain morphology are shown to affect K sub Ic. For 7001-T75 and 7079-T6, the order of decreasing fracture resistance with respect to crack propagation direction is short transverse, long transverse and longitudinal. For 7075-T6 the order is long transverse, short transverse, and longitudinal. (Author)

Descriptors :   *ALUMINUM ALLOYS), (*FRACTURE(MECHANICS), (*TOUGHNESS, ALUMINUM ALLOYS), CRACK PROPAGATION, NOTCH SENSITIVITY, STRAIN(MECHANICS), MECHANICAL PROPERTIES, FORGING, TENSILE PROPERTIES.

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE