Effect of cryogenic conditions on the critical crack tip opening displacement for the laminated material AA2519-AA1050-Ti6Al4V-T62

In the case of operating technical objects in conditions that accelerate material wear, it is necessary to adequately protect the object from the aggressive working environment. There are several possibilities, ranging from applying surface coatings (paint, varnish, galvanic layers) to the use of composites. An example of such a material is a composite formed by explosively welded AA2519, AA1050, and Ti6Al4V alloys. Since the described material is relatively new, its mechanical properties are still being determined. Therefore, in this article, the results of research and their analysis regarding the fracture toughness of the described composite in comparison to the fracture toughness of the base materials in the selected range are presented. The main objective of study was to determine the crack tip opening displacement (CTOD) values for the AA2519-AA1050-Ti6Al4V laminated material explosively welded under ambient and cryogenic conditions. The tests were carried out to determine the effect of the aforementioned temperature conditions on selected properties of the tested laminated material. This paper presents the theoretical basis and the adopted testing methodology. The experimental results obtained and their analysis are also presented. Thanks to the analysis, the effect of cryogenic conditions on the value of the crack tip opening displacement was observed. Moreover, the state of knowledge presented in earlier publications on crack tip opening displacement determination for base materials, i.e. AA2519 and Ti6Al4V, has been extended. The paper also presents a CTOD determination procedure for laminated material based on the knowledge on the mechanical properties of the base materials.