All posts by Raju Ravi

2 April 2019 @ 2pm: Seminar by Maya Katpadi Kini, Max Planck Dusseldorf

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)


18 Mar 2019 @ 2.30pm: PhD Defence by Ms. Swati Biswas (ERP)

Name of student   :   Ms. Swati Biswas (ERP)

Title                            : “Deformation Behaviour of a Directionally Solidified
                                          Nickel-based Superalloy Su 247LC DS at Elevated

Faculty Advisors   :    Prof Dipankar Banerjee , Prof. S. Karthikeyan
                                         & Dr. S. Ramachandra (Scientist G) (GTRE)

Date                           :    Monday  18th  March , 2019
Time                          :    02:30 PM
Venue                       :    Materials Engineering Lecture Theatre