Investigation of the intermetallic β'(B2)-phase in the Co–Al–Si system

Abstract

An experimental investigation of the structure and physical properties of the intermetallic β' (В2) phase in the Co–Al–Si system has been performed. It has been shown that alloying with silicon reduces the degree of long-range order and the lattice parameter of the B2 phase. It has been revealed that small additives of silicon (up to 3 at %) favor the formation of pores and cracks and lead to a strong embrittlement of the alloy. In the structure of the Co–39.5 at % Al–3 at % Si alloy after high-temperature homogenization at 1260°С for 30 h and slow cooling, prismatic dislocation loops of a specific cubic shape formed by edge dislocations with a Burgers vector а<100>(100) have been revealed. It has been shown experimentally that the changes in the magnetic properties of the weakly magnetic CoAl-based alloys can serve as an indicator of the degree of the defect nature of the crystal lattice of this intermetallic compound.