“…Taking into account that, for copper-tin alloys, the initial melting temperature (solidus) sharply decreases with rising of the tin content, from 1083°C for copper to 798°C for an alloy with 13,2% Sn (Sorokin, 1966), then molten copper-tin will exist in larger quantities and penetrate the solid iron boundaries. Liquid penetration of the grain boundaries causes grain separation and swelling on liquid formation.…”