Influence of Water-Jet on Micro-Formed Parts Process via Nano-Indentation and SEM Analysis

Abstract

Based on the experimental study of cavitation water jet impact on micro-forming, a single round hole micro-die was used in this paper. The effect of different process parameters on the performance of AISI 304 stainless steel foil was examined, which involves the nanometer hardness, and elastic modulus. The nano-indentation tester was used to test the nano-hardness of the formed part, and the performance of the workpiece before and after the impact was analyzed. The nano-hardness and elastic modulus increased significantly with an increase in the incident pressure. When the incident pressure was 20 MPa and the impact time of 5 min, the hardness increased by at least 122%, and the elastic modulus increased by at least 76%. After the cavitation water jet shocked the metallic foil of the SEM analysis and the results indicated that, as the incident pressure increases, the surface morphology of the formed part changes from approximately spherical to spherical, and the spherical roundness increases. In addition, there were different degrees of defects at the bottom of the formed part, and as the incident pressure increased, the bottom defects became more and more obvious, from micro-cracks to micro-layer cracks.