Mechanical properties and determination of slip systems of the B2 YZn intermetallic compound

Single crystal specimens of YZn (B2) were tested in tension at room temperature. Specimens with a [1 0 1] tensile axis orientation exhibited {0 1 1}〈1 0 0〉 primary slip and an ultimate tensile strength of 365 MPa at 3.7% elongation. Specimens with [0 0 1] and [1 1 1] tensile axis orientations showed no slip lines and fractured at a stress of 180 MPa at 3.3% and 130 MPa at 2.9% elongation, respectively. Transmission electron microscopy (TEM) examination of the Burger’s vector of dislocations in tensile tested specimens revealed 〈1 0 0〉-type dislocations. TEM analysis suggested that a secondary slip system, {0 0 1}〈1 0 0〉, may be active. Banded features with a {0 2 1} orientation were observed in deformed YZn; these may be slip traces produced by the cross-slip of 〈1 0 0〉 dislocations. Acting together, {0 1 1}〈1 0 0〉 and {0 0 1}〈1 0 0〉 slip provide only three independent slip systems, and no extra independent systems are provided by the cross-slip. This finding is consistent with the low ductility of YZn.