Components often manifest varied local behavior due to their manufacturing process. In order to be able to determine local material behavior in the best possible way, it is necessary to take specimens from the area under investigation. Due to constant developments in efficiency and lightweight construction, it is difficult to produce standard-compliant specimens from the examined area in a component. For this reason, specimens with smaller dimensions are often taken. Through the investigation of the influence of size in the area of high-cycle fatigue, it is well known that the size of a test specimen influences its lifespan. Not so much is known about the influence of specimen size on the behavior of material in the field of low-cycle fatigue (LCF). In this work, tensile, LCF and thermomechanical fatigue tests are performed using AlCu4PbMgMn with varied specimen geometries, the smallest test diameter being 3 mm, the largest 7.5 mm. The results of the tensile test show that the mean values of tensile strength for both diameters is within one percent. At LCF load and thermomechanical load, there are no or only slight deviations in deformation behavior. The low cycle fatigue behavior at RT is identical for both diameters. However, the results show that stress-strain behavior is the same for both test diameters, and fatigue behavior is the same, except in tests with high strain amplitudes and temperature.