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 rhenium and molybdenum, 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 2:1, said metal alloy having an average yield strength of at least about 98 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%, said metal alloy having a carbon to nitrogen atomic ratio of less than about 40:1 and an oxygen to nitrogen atomic ratio of less than about 30:1.
2. The stent as defined in claim 1 , wherein said metal alloy including over 99 weight percent of a solid solution.
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 less than about 50:1.
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 less than about 50:1.
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 , wherein said metal alloy has an average density of at least 13 gm/cc.
8. The stent as defined in claim 6 , wherein said metal alloy has an average density of at least 13 gm/cc.
9. The stent as defined in claim 1 , wherein said metal alloy includes about 46-49 weight percent rhenium and about 51-54 weight percent molybdenum.
10. The stent as defined in claim 8 , wherein said metal alloy includes about 46-49 weight percent rhenium and about 51-54 weight percent molybdenum.
11. The stent as defined in claim 2 , wherein said metal alloy includes at least about 99.9 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, and a carbon to oxygen atomic ratio of at least about 2:1.
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, and a carbon to oxygen atomic ratio of at least about 2:1.
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 atomic ratio of carbon to oxygen in said metal alloy is less than about 50:1.
17. The stent as defined in claim 15 , wherein said atomic ratio of carbon to oxygen in said metal alloy is less than about 50:1.
18. The stent as defined in claim 1 , wherein said metal alloy includes nitrogen, said nitrogen content of said metal alloy is less than about 20 ppm.
19. The stent as defined in claim 17 , wherein said metal alloy includes nitrogen, said nitrogen content of said metal alloy is less than about 20 ppm.
20. The stent as defined in claim 1 , wherein said metal alloy has an average grain size of about 6-9 ASTM.
21. The stent as defined in claim 19 , wherein said metal alloy has an average grain size of about 6-9 ASTM.
22. The stent as defined in claim 1 , wherein said metal alloy constitutes at least about 80 weight percent of said stent.
23. The stent as defined in claim 21 , wherein said metal alloy constitutes at least about 80 weight percent of said stent.
24. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<150 ppm
Mo
51–56%
O
<50 ppm
N
<20 ppm
Re
44–49%
and has an average grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of at least about 2:1 and Less than about 50:1, an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum is at least about 99.9 weight percent.
25. The stent as defined in claim 23 , wherein said metal alloy comprises by weight percent:
C
<150 ppm
Mo
51–56%
O
<50 ppm
N
<20 ppm
Re
44–49%
and has an average grain size of about 6-8 ASTM, a carbon to oxygen atomic ratio of at least about 2:1 and less than about 50:1, an average tensile elongation of about 25-350%, and said content of rhenium plus molybdenum is at least about 99.9 weight percent.
26. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5–55.5%
O
<10 ppm
N
<10 ppm
Re
44.5–47.5%
and has an average grain size of about 6-7 ASTM, a carbon to oxygen atomic ratio of at least about 2:1 and less than about 50:1, and an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum is at least about 99.9 weight percent.
27. The stent as defined in claim 25 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5–55.5%
O
<10 ppm
N
<10 ppm
Re
44.5–47.5%
and has an average grain size of about 6-7 ASTM, a carbon to oxygen atomic ratio of at least about 2:1 and less than about 50:1, and an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum is at least about 99.9 weight percent.
28. The stent as defined in claim 1 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5%
O
<10 ppm
N
<10 ppm
Re
47.5%
and has an average grain size of about 6-7 ASTM, a carbon to oxygen atomic ratio of at least about 2:1 and less than about 50:1, and an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum is at least about 99.9 weight percent.
29. The stent as defined in claim 27 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5%
O
<10 ppm
N
<10 ppm
Re
47.5%
and has an average grain size of about 6-7 ASTM, a carbon to oxygen atomic ratio of at least about 2:1 and less than about 50:1, and an average tensile elongation of about 25-35%, and said content of rhenium plus molybdenum is at least about 99.9 weight percent.
30. 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 and molybdenum, said metal alloy including carbon and oxygen and having a carbon to oxygen atomic ratio of at least about 2:1 and less than about 50:1, said metal alloy having a carbon to nitrogen atomic ratio of less than about 40:1 and an oxygen to nitrogen atomic ratio of less than about 30:1, said metal alloy having an average yield strength of about 98-122 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%, and including by weight percent:
C
<150 ppm
Mo
51–56%
O
<50 ppm
N
<20 ppm
Re
44–49%.
31. The stent as defined in claim 30 , wherein said metal alloy comprises by weight percent:
C
<50 ppm
Mo
52.5–55.5%
O
<10 ppm
N
<10 ppm
Re
44.5–47.5%
and an average grain size of about 6-7 ASTM.
32. The stent as defined in claim 2 , wherein said metal alloy including at least about 99.95 weight percent of a solid solution.