Mechanical properties of single crystal YCu and (Tb0.88Dy0.12)Zn B2 intermetallic compounds

Single crystal specimens of YCu with the B2-type crystal structure were tested in tension and in compression, and the isostructural single crystal specimens of B2 (Tb0.88Dy0.12)Zn were tested in tension. The YCu tensile specimens elongated several percent before fracture. The active slip systems in YCu in tension were found to be {100}〈010〉 (τCRSS=17 MPa) and {110}〈010〉 (τCRSS=18 MPa). Specimens of single crystal YCu were compression tested with the 〈100〉 direction as the compression axis, an orientation that puts no resolved shear stress on either the {100}〈010〉 or the {110}〈010〉. These compression tests resulted in high yield stresses followed by what is believed to be a stress-induced transformation to another crystallographic structure of YCu, the B27-type crystal structure. All specimens of (Tb0.88Dy0.12)Zn failed by brittle fracture.