Metal alloy for a stent

• US 20060200224A1
• Filed: 11/18/2005
• Published: 09/07/2006
• Est. Priority Date: 03/03/2005
• Status: Active Grant

• Current Assignee: Mirus LLC
• Original Assignee: ICON Interventional Systems, Inc.
• Inventors: Furst, Joseph G., Patel, Udayan, Buckman, Raymond W. Jr.
• Granted Patent: US 7,452,501 B2
• Time in Patent Office: Days
• US Class Current: 623/1.150
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: Y10S 606/907 Composed of particular material or coated

Abstract

A stent that is at least partially formed of a novel metal alloy, which novel metal alloy improves the physical properties of the stent.

Claims

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 99.9 weight percent of a solid solution of at least three metals, 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.

2. The stent as defined in claim 1, wherein said metal alloy including at least about 99.95 weight percent of a solid solution of at least three metals.

3. The stent as defined in claim 1, wherein said metal alloy has an average yield strength of at least about 110 ksi and an average ultimate tensile strength of at least about 100 ksi.

4. The stent as defined in claim 2, wherein said metal alloy has an average yield strength of at least about 110 ksi and an average ultimate tensile strength of at least about 100 ksi.

5. The stent as defined in claim 1, wherein said metal alloy has an average grain size of over 5 ASTM.

6. The stent as defined in claim 4, wherein said metal alloy has an average grain size of over 5 ASTM.

7. The stent as defined in claim 1, wherein said metal alloy has an average tensile elongation of at least about 25%.

8. The stent as defined in claim 6, wherein said metal alloy has an average tensile elongation of at least about 25%.

9. 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.

10. 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.

11. The stent as defined in claim 1, wherein said metal alloy has an average density of at least 13.5 gm/cc.

12. The stent as defined in claim 10, wherein said metal alloy has an average density of at least 13.5 gm/cc.

13. 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, zirconium, or mixtures thereof.

14. The stent as defined in claim 13, 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, zirconium, or mixtures thereof.

15. 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, 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%.

16. The stent as defined in claim 15, wherein said metal alloy includes at least about 99 weight percent of a solid solution of at least three metals.

17. The stent as defined in claim 15, wherein said metal alloy includes carbon and oxygen and having a carbon to oxygen atomic ratio of about 2.5-10:

1.

18. The stent as defined in claim 16, wherein said metal alloy including carbon and oxygen and having a carbon to oxygen atomic ratio of about 2.5-10:

1.

19. The stent as defined in claim 15, 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.

20. The stent as defined in claim 18, 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.

21. The stent as defined in claim 15, wherein said metal alloy has an average density of at least 13.5 gm/cc.

22. The stent as defined in claim 20, wherein said metal alloy has an average density of at least 13.5 gm/cc.

23. The stent as defined in claim 15, 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, zirconium, or mixtures thereof.

24. The stent as defined in claim 22, 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, zirconium, or mixtures thereof.

25. 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 rhenium, molybdenum and an additional metal, said metal alloy including at least about 40 weight percent rhenium and at least about 50 weight percent molybdenum 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, zirconium, or mixtures thereof.

26. The stent as defined in claim 25, wherein said metal alloy includes at least about 99.9 weight percent rhenium and molybdenum, said rhenium content about 44-48 weight percent of said alloy.

27. The stent as defined in claim 25, 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.

28. The stent as defined in claim 26, 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.

29. The stent as defined in claim 27, 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.

30. The stent as defined in claim 28, 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.

31. The stent as defined in claim 25, wherein said ratio of carbon to oxygen in said metal alloy is at least about 2.5:

1.

32. The stent as defined in claim 30, wherein said ratio of carbon to oxygen in said metal alloy is at least about 2.5:

1.

33. The stent as defined in claim 25, wherein said metal alloy includes nitrogen, said nitrogen content of said metal alloy is less than about 20 ppm.

34. The stent as defined in claim 32, wherein said metal alloy includes nitrogen, said nitrogen content of said metal alloy is less than about 20 ppm.

35. The stent as defined in claim 25, wherein said metal alloy has an average grain size of greater than about 5 ASTM.

36. The stent as defined in claim 34, wherein said metal alloy has an average grain size of greater than about 5 ASTM.

37. The stent as defined in claim 35, wherein said metal alloy has an average grain size of about 6-9 ASTM.

38. The stent as defined in claim 36, wherein said metal alloy has an average grain size of about 6-9 ASTM.

39. The stent as defined in claim 25, wherein said metal alloy has an average tensile elongation of at least about 25%.

40. The stent as defined in claim 38, wherein said metal alloy has an average tensile elongation of at least about 25%.

41. The stent as defined in claim 25, wherein said metal alloy constitutes at least about 80 weight percent of said stent.

42. The stent as defined in claim 40, wherein said metal alloy constitutes at least about 80 weight percent of said stent.

43. The stent as defined in claim 25, wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.2-5:

1.

44. The stent as defined in claim 42, wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.2-5:

1.

45. The stent as defined in claim 43, wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.5-3:

1.

46. The stent as defined in claim 44, wherein said metal alloy includes titanium and zirconium, said titanium and zirconium having a weight ratio of about 1.5-3:

1.

47. 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 44-50% Ti ≦

0.5% Y ≦

0.1% Zr ≦

0.25% 

and has a grain size of about 6-8 ASTM, a carbon to oxygen 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 99.9 weight percent.

48. The stent as defined in claim 46, wherein said metal alloy comprises by weight percent:

C <

150 ppm Mo 50-55% O <

100 ppm N  

<

40 ppm Re 44-50% Ti ≦

0.5% Y ≦

0.1% Zr ≦

0.25% 

and has a grain size of about 6-8 ASTM, a carbon to oxygen 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 99.9 weight percent.

49. 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 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 99.9 weight percent.

50. The stent as defined in claim 46, 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 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 99.9 weight percent.

51. 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 44.5-47.5% Ti ≦

0.4% Y ≦

0.1% Zr ≦

0.2%

and has a grain size of about 6-8 ASTM, a carbon to oxygen 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 99.9 weight percent.

52. The stent as defined in claim 46, wherein said metal alloy comprises by weight percent:

C <

50 ppm Mo 52.5-55.5% O <

20 ppm N <

20 ppm Re 44.5-47.5% Ti ≦

0.4% Y ≦

0.1% Zr ≦

0.2%

and has a grain size of about 6-8 ASTM, a carbon to oxygen 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 99.9 weight percent.

53. 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 44-48% 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 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 99.9 weight percent, said average yield strength at least about 110 ksi.

54. The stent as defined in claim 46, wherein said metal alloy comprises by weight percent:

C <

50 ppm Mo 52-56% O <

10 ppm N <

10 ppm Re 44-48% 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 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 99.9 weight percent, said average yield strength at least about 110 ksi.

55. 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 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 99.9 weight percent, said average yield strength at least about 110 ksi.

56. The stent as defined in claim 46, 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 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 99.9 weight percent, said average yield strength at least about 110 ksi.

57. 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, zirconium, or mixtures thereof, said metal alloy including carbon and oxygen and having a carbon to oxygen 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%

58. The stent as defined in claim 57, 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.

59. The stent as defined in claim 57, 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%

60. The stent as defined in claim 57, 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%

61. The stent as defined in claim 57, 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%

62. The stent as defined in claim 57, 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.

63. The stent as defined in claim 57, 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%

64. The stent as defined in claim 57, 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 0.004-0.06% Zr  

0.1-0.2%