Slip and Crack Initiation Behavior of Carbon Steel Thin Films under Cyclic In-Plane Shear Loading

Abstract

In the same materials, film and bulk materials show different mechanical properties. In fatigue testing of metallic thin film, several studies have been reported for axial and bending directions, however, there are few studies for shear direction. In addition, multiple parallel slips in the same grain are considered out-plane direction, a single linear slip in a grain is considered in-plane direction. Therefore, in this study we conducted fatigue tests under cyclic in-plane pure shear loading to S10C and S45C.We focused on the effect of pearlite volume fraction on slip generation and the relationship between cracks and slips. As a result, about 90% of the slip that occurred in S10C was out-plane direction. About 70% of the slip that occurred in S45C was in-plane slip. This is considered to be caused by the concentration of strain due to pearlite. In addition, more cracks were observed in S45C than in S10C, Consequently, cracks in the carbon steel film are considered to have grown from in-plane slip.