A series of micro-deep drawing experiments were conducted on stainless steel 304 foils with four thicknesses that were heat treated at four different temperatures. Due to heat treatments, a variety of different grain sizes and T/D ratios (the number of grains throughout thickness) were obtained. In this study, the limit drawing rations (LDR) of these foils were obtained; it has also been found that the factors that influence LRD of the foils include, but are not limited to, thickness, grain size, and T/D ratios. Tensile tests were conducted to obtain their mechanical properties that were used for two macroempirical equations to predict the maximum drawing load and LDR. It has been verified that the two equations can be applied to foils that are not thinner than 150 µm for reasonable predictions. However, the size effects are more noticeable and significant for the foils that are less than or equal to 100 µm so that the macroscale empirical equations cannot be applied to them.

Laser flexible shock micro-bulging (LFSB) is a novel micro fabrication technology, which combines laser dynamic forming and flexible die forming, which is a type of high strain rate micro-forming. The LFSB of 304 stainless steel foils was investigated in this paper. Experimental and simulated results indicated that the bulging depth and thickness thinning rate of bulging parts increased with an increase of laser energy and a decrease of workpiece thickness. Experimental results also showed the surface morphology of bulging parts. The hardness distribution in the cross section of bulging parts was revealed by nanoindentation experiments. The internal microstructure of micro bulging parts was observed by TEM. In addition, the equivalent stress and plastic strain distribution of bulging parts were shown in the numerical simulation under different workpiece thicknesses and laser energies.

Multilayer metal composite sheets possess superior properties to monolithic metal sheets, and formability is different from monolithic metal sheets. In this research, the feature size effect on formability of multilayer metal composite sheets under microscale laser flexible forming was studied by experiment. Two-layer copper/nickel composite sheets were selected as experimental materials. Five types of micro molds with different diameters were utilized. The formability of materials was evaluated by forming depth, thickness thinning, surface quality, and micro-hardness distribution. The research results showed that the formability of two-layer copper/nickel composite sheets was strongly influenced by feature size. With feature size increasing, the effect of layer stacking sequence on forming depth, thickness thinning ratio, and surface roughness became increasingly larger. However, the normalized forming depth, thickness thinning ratio, surface roughness, and micro-hardness of the formed components under the same layer stacking sequence first increased and then decreased with increasing feature size. The deformation behavior of copper/nickel composite sheets was determined by the external layer. The deformation extent was larger when the copper layer was set as the external layer.