Deformation of a C15 Laves phase: Twinning and synchroshear

In this paper the authors report on their studies of the cubic intermetallic compound, HfV2+Nb. The phase diagram of Hf-V-Nb system was established and two Laves phases fields were located. The physical and metallurgical properties of the C15 Laves phase were then studied. The mechanical properties of the C15 intermetallic compound were studied via compression tests at different temperatures and strain rates. It was found that the mechanical properties can be divided into three temperature regions: at low temperatures the alloy is fairly ductile due to the formation of (111)<112> type mechanical twinning, in the intermediate temperature region the alloy exhibits a ductility drop, and at high temperatures the alloy shows large plasticity via 1/2<110> dislocation slip. A new deformation twinning mechanism for complex intermetallic compounds is proposed based on the synchroshear mechanism. If the twins form in this way, then long shear vectors and/or atomic shuffles are not necessary