Influence of the theoretical load point on the value of the J - JQ integral during determination of fracture toughness of 2519 aluminium alloy

Abstract

The J integral is a value describing the fracture toughness of non-linear-elastic materials. One of such materials is the aluminum alloy AA2519. Due to the fact that it became the base material for the composite AA2519 - AA1050 - Ti6Al4V, it was decided to re-test this material. Due to the use of the aforementioned Al - Ti composite alloy AA2519 was also tested under cryogenic conditions. During the tests, its fracture toughness was determined using the J integral. Both in the method of one sample and many samples it is necessary to include the geometry of the sample. Currently, standard methods withdrawn, and did not describe all the required aspects of the research. During the time when the described material was created, the displacement point was not taken into account during the fracture toughness tests. Accordingly, there is a need to re-verify the determined once the fracture toughness of the described material. This article presents the author’s method of determining load displacement lines in compact samples (CT). It should be noted that this sample had an uncommonly encountered geometry. In the described case the width of the sample was four times the thickness.