Change in elastic properties during room-temperature aging in body-centered cubic Mg–Li and Mg–Li–Al single crystals

Abstract

• A complete set of elastic constants of Mg-40Li and Mg-40Li-5Al (at.%) single crystals, developed for biodegradable orthopedic implants, were measured. • The Young's moduli of the Mg-Li and Mg-Li-Al single crystals strongly depend on the crystallographic direction. • The Young's modulus along the 〈100〉 direction is approximately 21 GPa, which perfectly match with that of natural bones. • The Young's moduli along 〈100〉 in the Mg-40Li and Mg-40Li-5Al alloys changed during aging near room temperature, which was revealed for the first time. The elastic properties and room-temperature aging behaviors of body-centered cubic Mg–40Li and Mg–40Li–5Al (at.%) alloy single crystals, developed for biodegradable orthopedic implants, were investigated by measuring their single-crystalline elastic constants. It was found that the Young's moduli of Mg–40Li and Mg–40Li–5Al single crystals strongly depend on the crystallographic direction, and the Young's modulus along the 〈100〉 direction is approximately 21 GPa, which is almost the same as that of natural bones. More importantly, we found that the Young's moduli along < 100 > in the Mg–40Li and Mg–40Li–5Al alloys changed during aging near room temperature, which may have been caused by the precipitation or dissolution of the θ -phase MgAlLi 2 or hcp α-phase.