Things that Affect Young's Modulus?

Question

Question:

Does the Young’s modulus of an alloy change with heat treatment? Why or why not? Does the Young’s modulus of an alloy change with composition? Why or why not?

My Guess:

I think both answers are tied together and are both yes. I think that heat treating causes changes in microstructures, and different microstructures affect the Young's Modulus of a material.

Answer 1

Young's modulus does not change, for engineering purposes, for heat treatment. It is stress/strain, or how much the atoms pull apart or squeeze together under load. This is not affected by heat treatment, modest alloy changes, etc.

For example, plain carbon steels, low alloy steels all have essentially the same value. High alloy stainless is a few percent off from steel, because nickel and chrome and other alloys have a little different modulus than steel. When you have 50% nickel, you have to realize that the modulus is going to be an average between iron and nickel.

So alloys do change it, they basically average between the different components, as long as the phase structure doesn't change. For most low alloy materials, little or no difference.

Don't believe me? Look up Young's modulus for steels. All the same.