Nickel-titanium-yttrium alloys with reduced oxide inclusions

A nickel-titanium (NiTi) alloy, comprising:

• at least 20 wt. % nickel;
• between 35 wt. % titanium and 55 wt. % titanium;
• between 0.01 wt. % yttrium and 0.15 wt. % yttrium;
• and
• at least one of:
• copper between 1 wt. % and 10 wt. %, in lieu of an equal amount of nickel;
• niobium between 1 wt. % and 15 wt. %, in lieu of an equal amount of titanium;
• hafnium between 0.5 wt. % and 50 wt. %, in lieu of an equal amount of titanium;
• zirconium between 0.5 wt. % and 35 wt. %, in lieu of an equal amount of titanium;
• cobalt between 0.1 wt. % and 5 wt. %, in lieu of an equal amount of titanium, nickel, or a combination of titanium and nickel;
• chromium between 0.1 wt. % and 1 wt. %, in lieu of an equal amount of titanium;
• and
• iron between 0.1 wt. % and 10 wt. %, in lieu of an equal amount of titanium, nickel, or a combination of titanium and nickel.

A method of making a nickel-titanium (NiTi) alloy, comprising:

• providing at least 20 wt. % nickel;
• providing between 35 wt. % titanium and 55 wt. % titanium;
• providing between 0.01 wt. % yttrium and 0.15 wt. % yttrium;
• providing at least one of:
• copper between 1 wt. % and 10 wt. %, in lieu of an equal amount of nickel;
• niobium between 1 wt. % and 15 wt. %, in lieu of an equal amount of titanium;
• hafnium between 0.5 wt. % and 50 wt. %, in lieu of an equal amount of titanium;
• zirconium between 0.5 wt. % and 35 wt. %, in lieu of an equal amount of titanium;
• cobalt between 0.1 wt. % and 5 wt. %, in lieu of an equal amount of titanium, nickel, or a combination of titanium and nickel;
• chromium between 0.1 wt. % and 1 wt. %, in lieu of an equal amount of titanium;
• and
• iron between 0.1 wt. % and 10 wt. %, in lieu of an equal amount of titanium, nickel, or a combination of titanium and nickel;
• and
• forming an ingot including the nickel, the titanium and the yttrium, the ingot further including at least one of the copper, the niobium, the hafnium, the zirconium, the cobalt, the chromium and the iron.