Influence of geometric shape of specimen in fatigue life characterization on welded joint in titanium alloy

From literature we can find many theories on description of behaviour of different kind of materials. But just a few of them take into account an exact correlation between theoretical and experimental applications. In many instances the behaviour of these materials could be represented in function of some characteristics as density, Young modulus and Poisson ratio. One material with good characteristics of these listed above, that has been subjected to examination in this study, could be represented by titanium alloy and in particular titanium alloy grade 5. This material is suitable for the majority of applications in aeronautical, aerospace and naval industries and biomedical area. To be used in the field mentioned above, often titanium must be incorporated in different structures that can be fabricated by welding process assembly. This new component could be more sensitive to crack initiation near the welded area due to the influence of the welding process. In this paper we try to elucidate some problems related to the fatigue life resistance of components, simulating the activity during the real life of an assembly. The results have been confirmed by fractography analysis of broken surfaces, with Scanning Electron Microscopy (SEM) and an optical microscope, and have been correlated through numerical analysis.