Enter the materials constant for starting stress dislocation movement (MPa), the strengthening coefficient (MPa-m^1/2), and the average grain diameter (m) into the Hall-Petch Calculator. The calculator will evaluate the yield stress.

## Hall-Petch Formula

The following formula is used to calculate the Hall-Petch.

YS = MC + K / SQRT(d)

Variables:

- YS is the yield stress (MPa)
- MC is the materials constant for starting stress dislocation movement (MPa)
- K is the strengthening coefficient (MPa-m^1/2)
- d is the average grain diameter (m)

To calculate the yield stress using the Hall-Petch equation, divide the strengthening coefficient by the square root of the grain diameter, then add the result to materials constant for starting stress dislocation movement.

## How to Calculate Yield Stress From Hall-Petch Equation?

The following steps outline how to calculate the yield stress using the Hall-Petch equation.

- First, determine the materials constant for starting stress dislocation movement (MPa).
- Next, determine the strengthening coefficient (MPa-m^1/2).
- Next, determine the average grain diameter (m).
- Next, gather the formula from above = YS = MC + K / SQRT(d).
- Finally, calculate the yield stress.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem:**

Use the following variables as an example problem to test your knowledge.

materials constant for starting stress dislocation movement (MPa) = 25

strengthening coefficient (MPa-m^1/2) = .40

average grain diameter (m) = .75

YS = MC + K / SQRT(d) =** ** ?