Acoustic Emission Evaluation and Mechanical Property Characterization of Stainless Steel Specimens Manufactured by Powder Based 3-D Printer

This research aims at establishing relationship between acoustic emission characteristics and mechanical properties of 3d-printed stainless steel specimens including 420 (SS 420) series and 316L (SS 316L) series. Acoustic emission (AE), one kind of nondestructive testing (NDT), is widely applied in structure health monitoring and crack detection during dynamic processes. Using AE method, it is possible to detect fracture events of a specimen during the whole process of mechanical testing. \ud Results of AE analysis accompanying tensile tests present similar AE properties but no distinct differences between the two series. In AE figures, there are notable characteristics which indicate yield point and break point for samples with high ductility, while the notable characteristics can only indicate break point for specimens with low ductility. Also, the cumulative AE hits tend to decrease with increasing porosity of samples. Mechanical properties of SS 420 and SS 316 specimens are far away from those of standard materials, which may be caused by low packing density during printing or insufficient sintering.\u