Slip transmission across multiple coherent twin boundaries in nanotwinned Ag
Maya Katpadi Kini, Max Planck Dusseldorf
Nanotwinned materials are studied extensively in literature owing to an excellent combination of strength and ductility. Recent observations on Cu bicrystals with a single coherent twin boundary (CTB) suggested perfect slip transmission, that is similar to cross slip. Although these studies suggest that CTBs are weak obstacles for slip transmission, a large number of CTBs in nanotwinned metals lead to increase in yield strength.
In the present study, nanotwinned Ag thin film with twin spacing from 20nm to 1mm was prepared by PVD and suitable thermal treatment. Micropillar compression tests were carried out on pillars with varying twin spacing. Perfect slip transfer was observed down to the scale of nanotwins despite increase in yield strength at smaller twin spacings. The study addresses size scaling due to weak constraints for dislocation motion and underlying deformation mechanisms. Further microscale mechanical behavior is compared with wafer curvature measurements.
Time: 2:00pm, Tuesday (2nd April 2019 )
Venue: Brahm Prakash Committee Room (BPCR)