Investigation of the Fracture Process of Explosively Welded AA2519–AA1050–Ti6Al4V Layered Material

Abstract

The study presents an analysis of the cracking process of explosive welded layered material AA2519–AA1050–Ti6Al4V (Al–Ti laminate) at ambient (293 K) and reduced (223 and 77 K) temperatures. Fracture toughness tests were conducted for specimens made of base materials and Al–Ti laminate. As a result of loading, delamination cracking occurred in the bonding layer of specimens made from Al–Ti laminate. To define the crack mechanisms that occur at the tested temperatures, a fracture analysis was made using a scanning electron microscope. Moreover, acoustic emission (AE) signals were recorded while loading. AE signals were segregated to link their groups with respective cracking process mechanisms. Numerical models of the tested specimens were developed, taking into account the complexity of the laminate structure and the ambiguity of the cracking process. A load simulation using the finite element method FEM allowed calculating stress distributions in the local area in the crack tip of the Al–Ti laminate specimens, which enabled the explanation of significant material cracking process development aspects. Results analysis showed an influence of interlayer delamination crack growth on the process of the Al–Ti laminate specimen cracking and the level of KQ characteristics at different temperatures.

Analytic Model of Maximal Experimental Value of Stress Intensity Factor KQ for AA2519–AA1050–Ti6Al4V Layered Material

“…It should be noted that the details of determining individual mechanical properties can be found in Boroński et al [ 24 ].…”

“…The diagrams so achieved for the considered Al-Ti are presented in Figure 9 and the test results are presented in Table 5. It should be noted that the details of determining individual mechanical properties can be found in Boroński et al [24].…”

“…where P Q -load determined on the basis of the experimental curve, B-sample thickness, W-nominal sample width and a-crack length. Details of those tests can be found in Boroński et al [24]. However, it needs to be stressed that the tests described were focused on the influence of delamination between particular layers of the Al-Ti material on the mechanical quantities characterizing the material fracture toughness.…”

Using AE Signals to Investigate the Fracture Process in an Al–Ti Laminate

“…Comprehensive and in-depth analysis of AE signals confirmed occurring various mechanisms of failure in the cracking process of the Al–Ti composite, which tested in the range of ambient to cryogenic temperatures [ 52 ].…”