A new high temperature shape memory alloy system based on the Ni₅₀Ti_50-XHf_X has been successfully developed. The experimental results show that the martensite transformation temperature increases significantly with an increase in Hf content. The elevating effect of Hf on the phase transformation temperature is much higher than that of Pd. The A_f phase transformation temperature can reach as high as 503 degree(s)C when the Hf content is 25%. Examination of the one-way shape memory effect displays that the fully reversible strain decreases slightly as the Hf content increases, but the alloy also possesses a relatively high fully reversible strain even though the Hf content is 25%. It was also found that the new high temperature shape memory alloys demonstrate a very good two-way shape memory effect after proper training.

Date Published: 1 May 1994
PDF: 9 pages
Proc. SPIE 2189, Smart Structures and Materials 1994: Smart Materials, (1 May 1994); doi: 10.1117/12.174065

Published in SPIE Proceedings Vol. 2189:
Smart Structures and Materials 1994: Smart Materials
Vijay K. Varadan, Editor(s)