Medical devices with cutting elements

1. A medical device, comprising:

an elongated catheter configured to be inserted into a body;

an inflatable balloon attached to the catheter; and

a cutting element carried by the balloon, the cutting element comprising an alloy having a nickel equivalent and a chromium equivalent within a first area of a Schaeffler diagram, the first area being defined by 12 equivalent chromium-zero equivalent nickel, 12 equivalent chromium-15.5 equivalent nickel, and 26 equivalent chromium-4.5 equivalent nickel,

wherein a chromium equivalent is equal to % Cr+% Mo+1.5×% Si+0.5×% Nb, a nickel equivalent is equal to % Ni+30×% C+0.5×% Mn, and the alloy comprising at least two phases, one of the phases being a martensitic phase;

wherein the alloy comprises from about 0.35% to about 0.65% by weight of carbon;

wherein the alloy comprises from about 12% to about 16% by weight of chromium, from about 0.5% to about 5% by weight of molybdenum, and iron.

2. The device of claim 1 , wherein the alloy comprises from about 0.5% to about 1.5% by weight of manganese.

3. The device of claim 1 , wherein the alloy comprises from about 76% to about 87% by weight of iron.

4. The device of claim 1 , wherein the alloy comprises from about 0.5% to about 1.5% by weight of manganese, less than or equal to about 0.5% by weight of silicon, and from about 69% to about 87% by weight of iron.

5. The device of claim 4 , wherein the alloy further comprises nickel and/or cobalt.

6. The device of claim 1 , further comprising a lubricious coating on the cutting element.

7. The device of claim 1 , further comprising an oxidized layer on the cutting element.

8. The device of claim 1 , wherein the alloy has a hardness of from about 49 to about 55 Rockwell Hardness C.