In 1945, Kê started research on internal friction and anelastic properties in metals at the University of Chicago where he accomplished advanced studies of grain-boundary relaxation and non-linear anelastic relaxation associated to interactions between point defects and dislocations. This work continued after he returned to China in 1949 where he made further progress. The Kê-type torsion pendulum bears his name, as well as the Kê grain-boundary internal friction peak. Kê also proposed the Kê grain-boundary model for disordered atomic groups. Kê also participated in the Manhattan Project and the Long-Range Radar projects.