Question

At what value of the index of strain rate sensitivity does the material behave superplastically?

(a) 0

(b) 0.2

(c) 0.4 – 0.9

(d) 1.0 – 1.2

I got this question during an online exam.

The above asked question is from Plastic Deformation topic in chapter Plastic Deformation and Creep in Crystalline Materials, Elastic, Anelastic and Viscoelastic Behaviour of Engineering Material & Metallurgy

Answer 1

The correct option is (c) 0.4 – 0.9

The explanation is: The relationship between stress and strain rate can be expressed as σ = A ϵm. Here, m represents the index of strain rate sensitivity. For m = 0.4 – 0.9, the material exhibits superplastic behavior.