Twinning during annealing in the 79NM alloy of different melting methods

The change in the number of annealing twins in the alloy 79NM in relation of the melting method and annealing conditions was studied. Annealing of metals differing in their impurity content and obtained by induction melting and electron-beam remelting is conducted at 1050-1200 deg C for 6 hr in a vacuum. It was established that the maximum magnetic permeability of the alloy is inversely proportional to the twin density in the metal. It is shown that the twin density in the grain and in the metal depends on the annealing temperature and the melting method. An increase in annealing temperature reduces the number of twins; this process is more active in open-melting metals, where the impurity concentration is higher