Metal alloy for a stent
View Patent ↗A stent that is at least partially formed of a novel metal alloy, which novel metal alloy improves the physical properties of the stent.
1. A stent that is at least partially formed of a metal alloy which improves the strength and ductility of the stent, said metal alloy including at least about 95 weight percent of a solid solution of at least three metals selected from the group consisting of rhenium, molybdenum, titanium, yttrium, and zirconium, said metal alloy including 45-50 weight percent rhenium and 50-55 weight percent molybdenum, said metal alloy includes a plurality of second phase particles, said second phase particles including carbides carbo-nitrides, oxides or mixtures thereof, said metal alloy including carbon and oxygen and having a carbon to oxygen atomic ratio of at least about 2.5:1, said metal alloy having an average yield strength of at least about 110 ksi and an average ultimate tensile strength of at least about 100 ksi, said metal alloy having an average grain size of over 5 ASTM, said metal alloy having an average tensile elongation of at least about 25%.
2. The stent as defined in claim 1 , wherein said metal alloy including over about 99 weight percent of a solid solution of at least three metals.
3. The stent as defined in claim 1 , wherein said metal alloy including carbon and oxygen and having a carbon to oxygen atomic ratio of about 2.5-10:1.
4. The stent as defined in claim 2 , wherein said metal alloy including carbon and oxygen and having a carbon to oxygen atomic ratio of about 2.5-10:1.
5. The stent as defined in claim 1 , wherein said metal alloy has a nitrogen content of less than about 20 ppm, a carbon content of less than about 150 ppm, and an oxygen content of less than about 50 ppm.
6. The stent as defined in claim 4 , wherein said metal alloy has a nitrogen content of less than about 20 ppm, a carbon content of less than about 150 ppm, and an oxygen content of less than about 50 ppm.
7. The stent as defined in claim 1 , said metal alloy has an average density of at least 13.5 gm/cc.
8. The stent as defined in claim 6 , wherein said metal alloy has an average density of at least 13.5 gm/cc.
9. The stent as defined in claim 1 , wherein said metal alloy includes about 46-49 weight percent rhenium, about 51-54 weight percent molybdenum, and about 0.02-0.5 weight percent additional metal, said additional metal including a metal selected from the group consisting of titanium, yttrium, and zirconium.
10. The stent as defined in claim 8 , wherein said metal alloy includes about 46-49 weight percent rhenium, about 51-54 weight percent molybdenum, and about 0.02-0.5 weight percent additional metal, said additional metal including a metal selected from the group consisting of titanium, yttrium, and zirconium.
11. The stent as defined in claim 2 , wherein said metal alloy includes at least about 99.5 weight percent rhenium and molybdenum.
12. The stent as defined in claim 1 , wherein said carbon content of said metal alloy is less than about 100 ppm and said oxygen content of said metal alloy is less than about 50 ppm.
13. The stent as defined in claim 10 , wherein said carbon content of said metal alloy is less than about 100 ppm and said oxygen content of said metal alloy is less than about 50 ppm.
14. The stent as defined in claim 12 , wherein said carbon content of said metal alloy is less than about 50 ppm and said oxygen content of said metal alloy is less than about 10 ppm.
15. The stent as defined in claim 13 , wherein said carbon content of said metal alloy is less than about 50 ppm and said oxygen content of said metal alloy is less than about 10 ppm.
16. The stent as defined in claim 1 , wherein said metal alloy includes nitrogen, said nitrogen content at said metal alloy is less than about 20 ppm.
17. The stent as defined in claim 15 , wherein said metal alloy includes nitrogen, said nitrogen content of said metal alloy is less than about 20 ppm.
18. The stent as defined in claim 1 , wherein said metal alloy has an average grain size of about 6-9 ASTM.
19. The stent as defined in claim 17 , wherein said metal alloy has an average grain size of about 6-9 ASTM.
20. The stent as defined in claim 1 , wherein said metal alloy constitutes at least about 80 weight percent of said stent.
21. The stent as defined in claim 19 , wherein said metal alloy constitutes at least about 80 weight percent of said stent.
22. The stent as defined in claim 1 , wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.2-5:1.
23. The stent as defined in claim 21 , wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.2-5:1.
24. The stent as defined in claim 22 , wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.5-3:1.
25. The stent as defined in claim 23 , wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.5-3:1.
26. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<150 ppm
Mo
50-55%
O
<100 ppm
N
<40 ppm
Re
up to 50%
Ti
≦0.5%
Y
≦0.1%
Zr
≦0.25%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35% and said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent.
27. The stent as defined in claim 25 , wherein said metal alloy comprises by weight percent:
C
<150 ppm
Mo
50-55%
O
<100 ppm
N
<40 ppm
Re
up to 50%
Ti
≦0.5%
Y
≦0.1%
Zr
≦0.25%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent.
28. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
51-54%
O
<20 ppm
N
<20 ppm
Re
46-49%
Ti
≦0.4%
Y
≦0.1%
Zr
≦0.2%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent.
29. The stent as defined in claim 25 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
51-54%
O
<20 ppm
N
<20 ppm
Re
46-49%
Ti
≦0.4%
Y
≦0.1%
Zr
≦0.2%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent.
30. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5-55.5%
O
<20 ppm
N
<20 ppm
Re
up to 47.5%
Ti
≦0.4%
Y
≦0.1%
Zr
≦0.2%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent.
31. The stent as defined in claim 25 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5-55.5%
O
<20 ppm
N
<20 ppm
Re
up to 47.5%
Ti
≦0.4%
Y
≦0.1%
Zr
≦0.2%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent.
32. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52-56%
O
<10 ppm
N
<10 ppm
Re
up to 48%
Ti
0.2-0.4%
Y
0-0.08%
Zr
0-0.2%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent, said average yield strength at least about 110 ksi.
33. The stent as defined in claim 25 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52-56%
O
<10 ppm
N
<10 ppm
Re
up to 48%
Ti
0.2-0.4%
Y
0-0.08%
Zr
0-0.2%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent, said average yield strength at least about 110 ksi.
34. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5-55%
O
<10 ppm
N
<10 ppm
Re
45-47.5%
Ti
0.3-0.4%
Y
0.005-0.05%
Zr
0.1-0.25%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent, said average yield strength at least about 110 ksi.
35. The stent as defined in claim 25 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5-55%
O
<10 ppm
N
<10 ppm
Re
45-47.5%
Ti
0.3-0.4%
Y
0.005-0.05%
Zr
0.1-0.25%
and has a grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of about 2.5-10:1, an average tensile elongation of about 25-35%, said content of rhenium plus molybdenum plus metal component is at least about 99.5 weight percent, said average yield strength at least about 110 ksi.
36. A stent that is formed of at least about 80 weight percent of a metal alloy which improves the strength and ductility of the stent, said metal alloy including at least about 99.9 weight percent of a solid solution of rhenium, molybdenum and an additional metal, said metal alloy including at least and effective amount and up to about 0.5 weight percent of said additional metal, said additional metal including a metal selected from the group consisting of titanium, yttrium, and zirconium, said metal alloy including 45-50 weight percent rhenium and 50-55 weight percent molybdenum, said metal alloy including carbon and oxygen and having a carbon to oxygen atomic ratio of at least about 2.5:1, said metal alloy having an average yield strength of at least about 110 ksi and an average ultimate tensile strength of about 100-150 ksi, said metal alloy having an average grain size of about 6-9 ASTM, said metal alloy having an average tensile elongation of about 25-35%, said metal alloy having an average density of at least about 13.5 gm/cm, and said metal alloy including by weight percent:
C
≦50 ppm
Mo
52-56%
O
≦20 ppm
N
≦10 ppm
Re
44-48%
Ti
0-0.4%
Y
0-0.08%
Zr
0-0.25%.
37. The stent as defined in claim 36 , wherein said metal alloy comprises by weight percent:
C
≦50 ppm
Mo
52.5-55%
O
≦10 ppm
N
≦10 ppm
Re
45-47.5%
Ti
0.3-0.4%
Y
0.005-0.05%
Zr
0.1-0.25%
and a weight ratio of titanium to zirconium is about 1.5-3:1.
38. The stent as defined in claim 36 , wherein said metal alloy comprises by weight percent:
C
≦40 ppm
Mo
51-53%
O
≦15 ppm
N
≦10 ppm
Re
47-49%
Ti
0.1-0.35%
Y
0%
Zr
0%.
39. The stent as defined in claim 36 , wherein said metal alloy comprises by weight percent:
C
≦40 ppm
Mo
51.5-54%
O
≦15 ppm
N
≦10 ppm
Re
46-48.5%
Ti
0%
Y
0.002-0.08%
Zr
0%.
40. The stent as defined in claim 36 , wherein said metal alloy comprises by weight percent:
C
≦40 ppm
Mo
52-55%
O
≦15 ppm
N
≦10 ppm
Re
45-48%
Ti
0%
Y
0%
Zr
0.01-0.2%.
41. The stent as defined in claim 36 , wherein said metal alloy comprises by weight percent:
C
≦40 ppm
Mo
52.5-55%
O
≦10 ppm
N
≦10 ppm
Re
45-47.5%
Ti
0.1-0.3%
Y
0%
Zr
0.05-0.15%
and a weight ratio of titanium to zirconium is about 1.5-3:1.
42. The stent as defined in claim 36 , wherein said metal alloy comprises by weight percent:
C
≦40 ppm
Mo
52-55%
O
≦10 ppm
N
≦10 ppm
Re
45-49%
Ti
0.05-0.4%
Y
0.005-0.07%
Zr
0%.
43. The stent as defined in claim 36 , wherein said metal alloy comprises by weight percent:
C
≦40 ppm
Mo
52.5-55.5%
O
≦10 ppm
N
≦10 ppm
Re
44.5-47.5%
Ti
0%
Y
0.004-0.060%
Zr
0.1-0.2%.
44. The stent as defined in claim 1 , wherein said metal alloy includes 0.02-0.5 weight percent titanium.
45. The stent as defined in claim 2 , wherein said metal alloy including at least about 99.95 weight percent of a solid solution of at least three metals.