US4780154A — Shape memory alloy and method for producing same

Claim 1

Independent Claim 94 words

A polycrystalline alloy article which consists, by weight percentage of from 20% to 40% of Mn, from 3.5% to 8% of Si, and the balance Fe and unavoidable impurities which is essentially comprised of a ε phase at room temperature prior to plastic working, in which an γ phase is formed by plastic working at an Md temperature point (point of martensitic transformation by plastic working) or lower temperature, and which memorizes a shape thereof prior to said plastic working upon heating to an As point (the ε→γ transformation starting point) or higher temperature.

Claim 2

Dependent Claim 94 words

A polycrystalline alloy article which consists, by weight percentage of from 20% to 40% of Mn, from 3.5% to 8% of Si, and the balance Fe and unavoidable impurities which is essentially comprised of a ε phase at room temperature prior to plastic working, in which an γ phase is formed by plastic working at an Md temperature point (point of martensitic transformation by plastic working) or lower temperature, and which memorizes a shape thereof prior to said plastic working upon heating to an As point (the ε→γ transformation starting point) or higher temperature.

Claim 3

Dependent Claim 47 words

A polycrystalline alloy article according to claim 1, wherein a predetermined shape thereof is imparted by hot-rolling and the alloy article prior to said plastic working is not less than 85% of the γ phase and not more than 15% of the ε phase at room temperature.

Claim 4

Dependent Claim 30 words

A polycrystalline alloy article according to claim 2, wherein the shape is predetermined by subjecting the alloy to warm working at a temperature of the Md point or higher temperature.

Claim 5

Dependent Claim 35 words

A polycrystalline alloy article according to claim 1, produced by hot-rolling, warm-working at said Md point or higher temperature, and subsequently annealing at a temperature equal to or higher than an austenite-transformation finishing temperature (Af).

Claim 6

Dependent Claim 41 words

A polycrystalline alloy article according to claim 4, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, and, further, subsequent to the hot-rolling cooling at a rate of 20° C./minute or less.

Claim 7

Dependent Claim 67 words

A polycrystalline alloy article according to claim 4, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, and, further, subsequent to the hot-rolling, holding, in the course of cooling, at a temperature range not lower than an Ms point and not higher than 800° C. for a time period of 5 minutes or longer, and then further cooling.

Claim 8

Dependent Claim 60 words

A polycrystalline alloy article according to claim 4, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, and, further subsequence to the hot-rolling and cooling, reheating to a temperature range not lower than the Af point and hot higher than 800° C. and annealing in said temperature range, followed by cooling.

Claim 9

Dependent Claim 158 words

A polycrystalline alloy article which consists, by weight percentage, of from 20% to 40% of Mn; from 3.5% to 8% of Si; at least one alloying element selected from the group consisting of (a), (b), and (c); (a) not more than 10% each of at least one element selected from the group consisting of Cr, Ni, and Co; (b) not more than 2% of Mo; and (c) not more than 1% each of at least one element selected from the group consisting of C, Al, and Cu; and the balance Fe and unavoidable impurities which is essentially comprised of γ phase at room temperature prior to plastic working, in which an ε phase is formed by plastic working at an Md temperature point (point of martensitic transformation by plastic working) or lower temperature, and which memorizes a shape thereof prior to said plastic working upon heating to an As point (the ε→γ transformation starting point) or higher temperature.

Claim 10

Dependent Claim 158 words

A polycrystalline alloy article which consists, by weight percentage, of from 20% to 40% of Mn; from 3.5% to 8% of Si; at least one alloying element selected from the group consisting of (a), (b), and (c); (a) not more than 10% each of at least one element selected from the group consisting of Cr, Ni, and Co; (b) not more than 2% of Mo; and (c) not more than 1% each of at least one element selected from the group consisting of C, Al, and Cu; and the balance Fe and unavoidable impurities which is essentially comprised of γ phase at room temperature prior to plastic working, in which an ε phase is formed by plastic working at an Md temperature point (point of martensitic transformation by plastic working) or lower temperature, and which memorizes a shape thereof prior to said plastic working upon heating to an As point (the ε→γ transformation starting point) or higher temperature.

Claim 11

Dependent Claim 47 words

A polycrystalline alloy article according to claim 8, wherein a predetermined shape thereof is imparted by hot-rolling and the alloy particle prior to said plastic working is not less than 85% of the γ phase and not more than 15% of the ε phase at room temperature.

Claim 12

Dependent Claim 31 words

A polycrystalline alloy article according to claim 9, wherein the shape is predetermined by further subjecting the alloy to warm working at a temperature of the Md point or higher temperature.

Claim 13

Dependent Claim 34 words

A polycrystalline alloy article according to claim 8, produced by hot-rolling warm-working at said Md point or higher temperature, and subsequently annealing at a temperature equal to or higher than austenite-transformation finishing temperature (Af).

Claim 14

Dependent Claim 41 words

An polycrystalline alloy article according to claim 11, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, and, further subsequent to the hot-rolling, cooling at a rate of 20° C./minute or less.

Claim 15

Dependent Claim 67 words

An polycrystalline alloy article according to claim 11, wherein the Mn content is form 26% to 34% and the Si content is from 4% to 7%, and, further, subsequent to the hot-rolling, holding, in the course of cooling, at a temperature range not lower than an Ms point and not higher than 800° C. for a time period of 5 minutes or longer, and then further cooling.

Claim 16

Dependent Claim 60 words

An polycrystalline alloy article according to claim 11, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, and, further, subsequent to the hot-rolling and cooling, reheating to a temperature range not lower than the Af point and not higher than 800° C. and annealing in said temperature range, followed by cooling.

Claim 17

Independent Claim 47 words

A method for producing a shape memory polycrystalline alloy article, comprising the steps of: obtaining an alloy consisting of from 20% to 40% of Mn, from 3.5% to 8% of Si, and the balance Fe and unavoidable impurities, hot-rolling said alloy article to obtain a predetermined shape.

Claim 18

Independent Claim 47 words

A method for producing a shape memory polycrystalline alloy article, comprising the steps of: obtaining an alloy consisting of from 20% to 40% of Mn, from 3.5% to 8% of Si, and the balance Fe and unavoidable impurities, hot-rolling said alloy article to obtain a predetermined shape.

Claim 19

Dependent Claim 53 words

A method according to claim 15, further comprising the steps of: subsequent to said hot-rolling warm-rolling or wire drawing at a temperature range not lower than an Md point (point of martensitic transformation by plastic working) and annealing at a temperature of an Af point (an austenite transformation finishing temperature) or higher temperature.

Claim 20

Dependent Claim 42 words

A method according to claim 15, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, further comprising a step of cooling, subsequent to said hot-rolling, at a rate of 20° C./minute or less.

Claim 21

Dependent Claim 71 words

A method according to claim 15, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, further comprising the steps of: cooling subsequent to said hot-rolling; holding, in the course of said cooling, at a temperature range not lower than the Ms point and not higher than 800° C. for a period of 5 minutes or longer; and subsequently cooling to room temperature.

Claim 22

Dependent Claim 60 words

A method according to claim 15, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, further comprising the steps of: subsequent to said hot-rolling, cooling; reheating to a temperature range not lower than an Af point and not higher than 800° C.; and annealing in said temperature range, followed by cooling.

Claim 23

Independent Claim 115 words

A method for producing a shape memory polycrystalline alloy article, comprising the steps of: obtaining a polycrystalline alloy article consisting of from 20% to 40% or Mn; from 3.5% to 8% of Si; at least one alloying element selected from the group consisting of (a), (b), and (c): (a) not more than 10% each of at least one element selected from the group consisting of Cr, Ni, and Co; (b) not more than 2% of Mo; and (c) not more than 1% each of at least one element selected from the group consisting of C, Al, and Cu; and the balance Fe and unavoidable impurities, and hot-rollrng said alloy article to obtain a predetermined shape.

Claim 24

Independent Claim 115 words

A method for producing a shape memory polycrystalline alloy article, comprising the steps of: obtaining a polycrystalline alloy article consisting of from 20% to 40% or Mn; from 3.5% to 8% of Si; at least one alloying element selected from the group consisting of (a), (b), and (c): (a) not more than 10% each of at least one element selected from the group consisting of Cr, Ni, and Co; (b) not more than 2% of Mo; and (c) not more than 1% each of at least one element selected from the group consisting of C, Al, and Cu; and the balance Fe and unavoidable impurities, and hot-rollrng said alloy article to obtain a predetermined shape.

Claim 25

Dependent Claim 51 words

A method according to claim 20, further comprising the steps of: subsequent to said hot-rolling, warmrolling or wire-drawing at a temperature range not lower than the Md point (point of martensitic transformation by plastic working) and annealing at a temperature of an Af point (an austenite transformation finishing temperature) or higher.

Claim 26

Dependent Claim 42 words

A method according to claim 20, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, further comprising a step of cooling, subsequent to said hot-rolling, at a rate of 20° C./minute or less.

Claim 27

Dependent Claim 69 words

A method according to claim 20, wherein the Mn contents from 26% to 34% and the Si content is from 4% to 7%, further comprising the steps of: cooling subsequent to said hot-rolling; holding, in the course of said cooling, at temperature range not lower than the Ms point and not higher than 800° C. for a period of 5 minutes or longer; and subsequently cooling to room temperature.

Claim 28

Dependent Claim 60 words

A method according to claim 20, wherein the Mn content is from 26% to 34% and the Si content is from 4% to 7%, further comprising the steps of: subsequent to said hot-rolling cooling; reheating to a temperature range not lower than an Af point and not higher than 800° C.; and annealing in said temperature range, followed by cooling.

Claim 29

Dependent Claim 117 words

A polycrystalline alloy article consisting essentially of from 20% to 40% of Mn, from 3.5% to 8% of Si, and the balance Fe and unavoidable impurities, said article having a memorized predetermined shape and having been produced by the process comprising: providing said alloy article in said predetermined shape at room temperature and essentially comprised of γ phase; plastically deforming said alloy article at an Md temperature point or lower temperature thereby transforming said γ phase to ε phase; heating said plastically deformed alloy article to an As temperature point or higher temperature thereby transforming said ε phase to γ phase wherein said deformed alloy article returns to said predetermined shape as a result of said heating.

Claim 30

Dependent Claim 117 words

A polycrystalline alloy article consisting essentially of from 20% to 40% of Mn, from 3.5% to 8% of Si, and the balance Fe and unavoidable impurities, said article having a memorized predetermined shape and having been produced by the process comprising: providing said alloy article in said predetermined shape at room temperature and essentially comprised of γ phase; plastically deforming said alloy article at an Md temperature point or lower temperature thereby transforming said γ phase to ε phase; heating said plastically deformed alloy article to an As temperature point or higher temperature thereby transforming said ε phase to γ phase wherein said deformed alloy article returns to said predetermined shape as a result of said heating.

Claim 31

Independent Claim 113 words

A method of providing a shape memory polycrystalline alloy article comprising: providing at room temperature a polycrystalline alloy article consisting essentially of from 20% to 40% of Mn, from 3.5% to 8% of Si, the balance Fe and unavoidable impurities, with said allow article having a predetermined shape and essentially comprised of γ phase; plastically deforming said alloy article at an Md temperature point or lower temperature thereby transforming said γ phase to ε phase; heating said plastically deformed alloy article to an As temperature point or higher temperature thereby transforming said ε phase to γ phase whereby said deformed alloy article returns to said predetermined shape as a result of said heating.

Claim 32

Independent Claim 113 words

A method of providing a shape memory polycrystalline alloy article comprising: providing at room temperature a polycrystalline alloy article consisting essentially of from 20% to 40% of Mn, from 3.5% to 8% of Si, the balance Fe and unavoidable impurities, with said allow article having a predetermined shape and essentially comprised of γ phase; plastically deforming said alloy article at an Md temperature point or lower temperature thereby transforming said γ phase to ε phase; heating said plastically deformed alloy article to an As temperature point or higher temperature thereby transforming said ε phase to γ phase whereby said deformed alloy article returns to said predetermined shape as a result of said heating.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-10-25	1992-04-25	1992-10-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-10-25	1996-04-25	1996-10-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-10-25	2000-04-25	2000-10-25	$7700.00	Window Closed / Lapsed

Shape memory alloy and method for producing same

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