Material Property Evolution in Incremental Sheet Forming - A Review and Comparison

The last decade has shown an expanding interest towards incremental sheet forming (ISF). The present paper focuses on a wide variety of materials used in ISF with emphasis on material behavior and post forming properties. Material behavior knowledge is essential for improving process control and accuracy, post forming properties are essential for introducing ISF for wider industrial use. Included in the study are: a ferritic and four austenitic stainless steel grades, a deep drawing steel, as well as copper and silver. The two latter materials have been widely used for crafted products trough centuries and still have their place in high-end products. The suitability of the different materials for ISF is studied and compared. A comprehensive testing procedure is performed to gain information about behavior during and properties after deformation. The material property evolution is also compared to other forming methods to further enhance understanding of the process. The materials can be divided into stable and metastable materials. Stainless steels are an increasingly important class of alloys that are widely used in industry today. The structure of austenitic stainless steels is metastable which may lead to phase transformation. Strain induced martensite phases can form during plastic deformation of these steels. The formation of martensite affects significantly their mechanical behavior by enhancing the work hardening. Transformation impedes the property prediction as it is linked to the process conditions which may vary during forming. The stable materials lack phase transformation but show both diverse and similar material property evolution as a result of ISF.