Mechanical properties of yttrium hydride

The various shapes of flaw-free bulk yttrium hydrides could be fabricated and various mechanical properties were obtained. The lattice parameter decreased with the hydrogen content. The yttrium hydride had larger elastic moduli than the metal and the elastic moduli were dependent on the hydrogen content. The microhardness of the hydride was also larger than that of the metal and increased with hydrogen addition. The Debye temperature of the yttrium hydride estimated from the sound velocities and the lattice parameters was larger than that of pure yttrium metal. The hardness to Young's modulus ratio for the yttrium hydride is larger than the ratio for the titanium hydride or zirconium hydride.