Hydrogen-induced microstructure, texture and mechanical property evolutions in a high-pressure torsion processed zirconium alloy

The gaseous hydriding-induced evolutions of the microstructure, texture and mechanical properties of Zircaloy-4 processed by

high-pressure torsion (HPT) were assessed. Much d-ZrH1.66 precipitation at 15 atm (21%) incurred significant hardening of vacuumannealed HPT samples, and pure e-ZrH2 obtained at 20 atm showed a superior microhardness of 470 HV0.3 and a low fracture toughness of 0.63 MPa m1/2. The d-hydrides presented strong (11 1) texture and followed the (0001)a-Zr//{111}d-ZrH1.66 orientation relationship with the a-Zr matrix. During hydriding, a-Zr recrystallization texture was developed from the initial deformation texture.