Abstract: | Polycrystalline YCu specimens with a CsCl‐type B2 structure made by induction melting were investigated by transmission electron microscopy (TEM). TEM studies show that an orthorhombic YCu B27 martensite with FeB‐type structure having lattice parameters a = 0.71 nm, b = 0.45 nm and c = 0.54 nm forms during deformation at ambient temperature. (101) twins are observed in the YCu B27 phase. The orientation relationship of B27 with B2 matrix is (001)[1 0]B27 ‖ (112)[1 0]B2. Effects of B27 phase formation on the ductility of YCu alloy are discussed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) |