Study On Fatigue Performance Of 2A70 Aluminum Alloy Under Different Standard Printing Process

2A70 aluminum alloy is used in many parts of aero-engine,which suffer from fatigue damage due to long-term alternating load,and the service safety and life of aircraft are significantly affected.On the aero-engine,due to components installation,fault tracing and other reasons,we have to conduct marking processing on aircraft parts.If the selected marking method is not applicable to the selected materials and service conditions,it is likely to lead to a major accident.Moreover,there are very few studies on the selection of suitable marking technology for alloys in the light of service conditions.Therefore,it is of great significance to study the influence of different marks on the microstructure evolution,mechanical properties and fatigue properties of 2A70 aluminum alloy.The vibration and laser marking of 2A70 aluminum alloy were carried out and the tensile test was carried out.The results show that the mechanical properties of vibration marking are slightly better than laser marking.Abaqus software was used to calculate the stress concentration coefficients near different marks.To prepare for the following analysis of fatigue fracture mechanism of different marks.High cycle fatigue tests were carried out on 2A70 aluminum alloy base material and two kinds of post-marking samples.The results show that the high cycle fatigue life of the sample after laser marking is only 15.1%of that after vibration marking.The stress concentration near the vibration mark is smaller,the size of S 'phase and A19FeNi phase is smaller,and the volume fraction is higher.The high cycle fatigue performance of vibration-labeled specimens is better than that of laser labeled specimens due to the combined action of stress concentration,precipitation phase size and volume fraction.The low cycle fatigue behavior and fracture mechanism of 2A70 aluminum alloy after two kinds of marking were studied.The microstructure and crack initiation and propagation mechanism were analyzed.The results show that the high cycle fatigue life of the sample after laser marking is only 3.2%of that after vibration marking.The stress concentration and plastic deformation degree are smaller near the vibration mark.At the same time,scanning electron microscope and optical microscope were used to observe the fracture surface.EDS was used to analyze the element composition of the lateral tissue of fracture.The size and volume fraction of precipitated phase were measured using image tool software.