Comparative study of mechanical properties using standard and micro-specimens of base materials Inconel 625, Inconel 718 and Ti-6Al-4 V

To improve innovative joining and deposition technologies for the construction of dissimilar joints, precise knowledge of the local mechanical properties of materials must be obtained. In the present article a comparative study of the tensile properties and fatigue behaviour in case of flat standard and micro-specimens of base materials Inconel 625, Inconel 718 and Ti-6Al-4 V was accomplished. The aim of the study was to develop an efficient method for the investigation of the local mechanical properties by the use of micro-specimens subjected to electro discharge machining treatment and to obtain reliable tensile and fatigue test results. By the miniaturization of specimens a significant effect of roughness on mechanical properties was obtained. By considering a correction for the effective load-bearing cross-section the data obtained from micro-specimens are within 3% error with respect to standard specimen results. The results showed that the proposed technique can be successfully used to determine the tensile and fatigue properties of a small material volume.