Martensitic transformation and shape memory effect at very high temperatures in HfPd, and TiAu intermetallic compounds

Two intermetallic compounds, HfPd and TiAu have been analyzed as potential high temperature shape memory alloys. In spite of a reversible martensitic transformation detected at high temperature in HfPd, no meaningful shape recovery has been observed in this compound by TMA after compression pre-strain of the martensite.The mechanical properties of TiAu at high temperatures have been evaluated by thermal cycling under compression load and by compression tests. A high mobility of the dislocations is found around martensitic transformation temperatures, which limits the functional properties of this high temperature shape memory alloy. Some improvement should be obtained by precipitation hardening.

► The shape memory properties are studied for the first time in HfPd.
► No meaningful shape recovery is observed in HfPd after compression strain of the martensite.
► The potential use of TiAu as a shape memory alloy able to produce a work at high temperature is evaluated.
► The high mobility of the dislocations found in TiAu around its martensitic transformation temperature limits the functional properties of this compound.