The T5 Isochronal Age-Hardening Response of As-Solidified Mg–Li–RE–(Al)Alloys

Author(s):

Taylor Cain and Joseph Labukas

Abstract:

This investigation sought to explore the age hardenability of Mg–Li–RE–(Al) alloys where RE = Gd, Y, Nd. Alloys were made by induction melting and furnace cooling. The resulting as-solidified alloys were subjected to isochronal heat treatment of 2 h at temperatures between 150–400 °C followed by water quenching. Hardness measurements revealed Mg–Li–RE alloys containing Al displayed a U-shaped age-hardening effect where the hardness was large at low and high temperatures but decreased at intermediate temperatures. On the contrary, Mg–Li–RE alloys sans Al did not show an age-hardening response, likely due to precipitation of RE-rich phases upon solidification. Correlations of hardness with historical tensile data of Mg–Li alloys indicate that Mg–Li–RE alloys are not likely to be considered for structural applications.