Question

What is the Hall-Petch constant for Iron?

(a) 0.068

(b) 0.11

(c) 0.71

(d) 1.77

I have been asked this question by my school teacher while I was bunking the class.

This key question is from Plastic Deformation topic in division Plastic Deformation and Creep in Crystalline Materials, Elastic, Anelastic and Viscoelastic Behaviour of Engineering Material & Metallurgy

Answer 1

Right option is (c) 0.71

To explain I would say: The grain-boundary strengthening method is otherwise known as Hall-Petch method. The Hall-Petch constant is denoted as k and has a constant value of 0.71 for Iron. This constant for aluminum, copper, and molybdenum is 0.068, 0.11, and 1.77 in that order.