The phase stability and magnetic properties of the parent phase in the Co2Cr(Al,Si) shape memory alloys were systematically investigated. For the Co-rich portion in the vicinity of stoichiometric composition, the phase boundaries of B2 phase in equilibrium with Co solid solution (A1) phase at 1473 K were identified and the compositions showing martensitic transformation were also determined within the B2 single-phase region. The addition of Si greatly expands the B2 single-phase region compared with that of the Co-Cr-Al ternary system. The Curie temperature and spontaneous magnetization of the L21 phase, which is formed by the order-disorder transition from the B2 phase during water quenching from 1473 K, were 345–540 K and 2.1–2.6 μB/f.u., respectively. The values of spontaneous magnetization were lower than those expected from the Generalized Slater-Pauling rule and the ab-initio calculation.
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