Abstract A method of manufacturing a high-temperature shape memory alloy includes the steps of cold-working a high-temperature shape memory alloy, in which a reverse martensite transformation start temperature (As) in a first heating after cold working reaches 350° C. or above. Thereafter, the cold-worked alloy undergoes a first heat treatment for a period of time within the incubation time required for recrystallization or less, and at a temperature higher than a reverse martensite transformation finish temperature (Af). Finally, the resultant alloy is annealed with a second heat treatment, at a temperature which is not less than the plastic strain recovery temperature and not more than the recrystallization temperature. Specifically, the first heat treatment is performed for a period of three minutes or less at a temperature which exceeds 500° C. and which is lower than the melting point of the alloy. The composition of the high-temperature shape memory alloy is Ti 50 Ni 50-x Pd x (x being 35 to 50 at %), Ti 50-x Ni 50 Zr x (x being 22 to 30 at %), Ti 50-x Ni 50 Hf x (x being 20 to 30 at %) or the like.
Inventors
👤 Dmitrii Victorovich Golberg
👤 Kazuhiro Otsuka
👤 Tatsuhiko Ueki
👤 Hiroshi Horikawa
👤 Kengo Mitose
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-03 02:12
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/006
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
135 words
A method of manufacturing a high-temperature shape memory alloy, comprising the steps of: cold-working a high-temperature shape memory alloy, so that a reverse martensite transformation start temperature (As) of the alloy reaches 350° C. or above and a reverse martensite transformation finish temperature (A F ) of the alloy exceeds the recrystallization temperature of the alloy; thereafter subjecting the cold-worked alloy to a first heat treatment at a first temperature above the recrystallization temperature, for a period of time sufficiently short to prevent the start of recrystallization, said first temperature being higher than the A f temperature; and then annealing the resultant alloy in a second heat treatment, at a second temperature which is not less than the plastic strain recovery temperature of the alloy and not more than the recrystallization temperature of the alloy.
Claim 2
Independent Claim
135 words
A method of manufacturing a high-temperature shape memory alloy, comprising the steps of: cold-working a high-temperature shape memory alloy, so that a reverse martensite transformation start temperature (As) of the alloy reaches 350° C. or above and a reverse martensite transformation finish temperature (A F ) of the alloy exceeds the recrystallization temperature of the alloy; thereafter subjecting the cold-worked alloy to a first heat treatment at a first temperature above the recrystallization temperature, for a period of time sufficiently short to prevent the start of recrystallization, said first temperature being higher than the A f temperature; and then annealing the resultant alloy in a second heat treatment, at a second temperature which is not less than the plastic strain recovery temperature of the alloy and not more than the recrystallization temperature of the alloy.
Claim 3
Dependent Claim
46 words
A method of manufacturing a high-temperature shape memory alloy according to claim 1, wherein the first heat treatment is performed for a period of three minutes or less and wherein said first temperature exceeds 500° C. and is less than a melting point of the alloy.
Claim 4
Dependent Claim
80 words
A method of manufacturing a high-temperature shape memory alloy according to claim 1, wherein the composition of said high-temperature shape memory alloy is expressed, with numerical values representing at %, as Ti 50 Ni 50-x Pd x , in which X is 35 to 50 at %, Ti 50-x Ni 50 Zr x , in which X is 22 to 30 at %, or Ti 50-x Ni 50 Hf x , in which X is 20 to 30 at %.