why ferrous alloy will show the fatigue limit?

Question

and why non ferrous wont show the fatigue limitXD~


thx.!!

Answer 1

The Endurance or Fatigue limit is an important design data point that designers use to calculate how long a material can be expected to last when stressed to a calculated level.
They will usually try to limit their design stresses to be in that range of the fatigue curve that will give them an infinite number of cycles before fracture can be expected to occur.

Most non-ferrous alloys are so weak that they do not have endurance or fatigue limits that can be measured.
Also, Non Ferrous alloys are usually never used for load bearing components because they do not have sufficient strength to begin with, so this data wouldn't even be useful.

Answer 2

Don't really understand your question,
but I can guarantee, from personal experience,
that brass and aluminum will fatigue fracture.