Investigation Of The Magnetic Monitoring Technology For The Aluminum Alloy Fatigue

Aluminum alloy because of its superior performance,has been widely used in great quantities such as the aerospace, electronics, daily life, etc. But for its fatigue strength stress is more sensitive to concentration, prone to fatigue failure, major accidents were often caused by fatigue crack,so the study of the technology of monitor materials fatigue is significant.In view of the aluminum alloy material fatigue fracture,the paper puts forward a kind of magnetic nondestructive monitoring method in magnetic field environment. First, according to the change of the magnetic properties of aluminum alloy fatigue process, a magnetic monitoring principle is put forward. Second, the fatigue experiment of aluminum alloy were investigated, using group independent research and development of instruments monitor the test process magnetic number changes, get tired week cycle time and the curve of magnetic induction intensity, analysis this curve can exactly judge without fatigue fracture of the prefabricated defects sample point. On the curve fitting and differential treatment, can predict the fatigue life of aluminum alloy material, and through repeated test verifies the reliability of magnetic monitoring technology.At last, test the fatigue before and after fatigue fracture of magnetic susceptibility in the aluminum alloy sample by squid, found that fatigue fracture after aluminum alloy magnetic susceptibility get larger,verify the principle of magnetic method of aluminum alloy fatigue monitoring technology validity and feasibility.Determination of fatigue before and after fatigue fracture element content by EDS, found that fatigue fracture area rich iron,lead to magnetic susceptibility get larger,and fatigue life of aluminum alloy material is made up of calcium particles of impurities and the influence of iron content after fatigue fracture.Calcium impurity particles easily initiation of fatigue crack, shorten the fatigue life of aluminum alloy material.Fatigue fracture after iron content is more, the shorter the fatigue life of aluminum alloy material.Through monitoring fatigue experiments, the result shows that this method have very good monitoring effect to the fatigue fracture of aluminum alloy material.