Complex sentence: In 1974, Kaibyshev defended his doctoral dissertation and was a director of the SKTB "Tantal" with AIM from 1980 to 1986.
Split into simpler sentences: In 1974, Kaibyshev defended his doctoral dissertation. He established and became a director of the SKTB "Tantal" with AIM from 1980 to 1986.