Size effect of laser shock sheet bulk microforging.

In this paper, a new laser shock microforming method, laser shock sheet bulk microforging (LSSBMF), is put forward on the basis of the merit of sheet bulk forming and laser shock microforming. In this study, AZ31B magnesium alloy workpieces with different grain sizes, workpieces with different thicknesses, and microgroove dies with different widths are selected to evaluate the size effects on the forming properties. In the experiment, the influences of laser loading on grain size, grain size on depth of forming, and microhardness are studied. In the numerical simulation, the die geometry and workpiece size effects on the material forming process are analysed. The research results show that under the same laser energy loading, the larger the grain size is, the more obvious the grain size refinement phenomenon is. The forming depth increases with growing grain size, whereas the microhardness decreases. Numerical simulation results indicate that under the same laser energy loading, workpiece forming depth decreases with growing die feature groove width, whereas the equivalent plastic stress increases. The equivalent plastic stress increases with increasing workpiece thickness, whereas the forming depth decreases. [ABSTRACT FROM AUTHOR]