Experimental And Numerical Study On Microscale Laser Peen Forming Of Metallic Glass Strip

Metallic glass presents low-ductility in room temperature, therefore the practical applications are limited, although it has good mechanical, physical and chemical properties. Laser peen forming is a high stain rate plastic forming technology, which employs the shock wave pressure induced by laser pulse to deform sheet metal plastically. In this paper, the deformation and its mechanism of laser shocked metallic glass are studied.In the experiments, ND:YAG laser and Fe78Si9B13metallic glass strip with the thickness of30μm were adopted. The strip was clamped and supported by a rigid plate. The experiments were conducted in air without absorbent layers or confining overlays. The paper discussed the effect of the number of laser shocks and scanning passes on bending angle. The bending angle increases with the increase of shock number, and the increase rate decreases gradually. Meanwhile, with the increase of scanning passes, the bending angle increase linearly. We compared the thickness and microstructure of deformed area and unde formed area, which will help to discover the process mechanism of laser peen forming of metalic glass strips.The elasticity modulus, hardness, yield strength and the load-displacement curve of Fe78Si9B13metallic glass strip were obtained from the nanoindentation tests. The results show that there are large differences of mechanical properties between bulk and strip metallic glass.Finite element analysis software LS-Dyna was used to simulate the laser peen forming of Fe78Si9B13metallic glass strip. From this analysis, the displacement field, thickness, stress and strain field during deformation were obtained. The numerical model was simplified as two dimensional and was developed by using the finite element modeling software LS-Prepost.