Investigation of Strain Gradients and Magnitudes During Microbending

Sheet metal forming of parts with microscale dimensions is gaining importance due to the current trend toward miniaturization, especially in the electronics industry. In microforming, although the process dimensions are scaled down, the polycrystalline material stays the same (e.g., the grain size remains constant). When the specimen feature size approaches the grain size, the properties of individual grains begin to affect the overall deformation behavior. This results in inhomogeneous deformation and increased data scatter of the process parameters. In this research, the influence of the specimen size and the grain size on the distribution of plastic deformation through the thickness during a three-point microbending process is investigated via digital image correlation (DIC). Results showed that with miniaturization, a decrease in the strain gradient existed which matched previous research with respect to microhardness measurement.